Constipation / IBS-C are real problems which can cause significant inconvenience, discomfort, and even disability for some individuals. For most people, these are likely to be food sensitivity problems, as opposed to irreversible pathological diseases. Chronic constipation is not an inevitable consequence of aging; it can usually be alleviated by knowing which foods are gumming up the works.
Irritable Bowel Syndrome, or IBS, is commonly divided into two main types: IBS-C (IBS with constipation) and IBS-D (IBS with diarrhea). This article focuses on IBS-C.
Golden rule of IBS-C:
IBS-C is primarily about indigestion. If a food is hard to digest, it will slow things down. It’s that simple.
When exploring for yourself the connection between your symptoms and these foods, keep in mind that poorly-digested foods can cause delayed or prolonged symptoms because they are processed so slowly. Most of these foods can affect digestion for several days after you eat them. It is also important to recognize that sluggish digestion can cause all kinds of other problems north of the intestines, including heartburn, reflux (“GERD”), burping, and hiccups.
The five most common culprits:
Gluten and grains: Gluten is a sticky protein found in wheat, barley, rye, and triticale. This protein has a special globular structure that our enzymes can’t fully break down. Other grains can pose problems for our digestive tract, though, even those that don’t contain gluten, such as corn and oats. The grain that seems easiest on the innards may be rice, so some people may tolerate rice better than other grains.
Casein: Casein is a sticky protein found in most dairy products. Baby cows come with a special enzyme in their stomachs called rennet, which is designed especially to break down casein. Humans do not have rennet, so casein is very hard for us to digest. Hard cheeses and high-protein yogurts (such as “Greek style” yogurts) are especially good at triggering IBS-C.
Cruciferous veggies: Lots of veggies happen to be crucifers, including broccoli, kale, and cabbage. This veggie family contains high amounts of an indigestible short-chain carbohydrate (or oligosaccharide) called raffinose. Human enzymes cannot break down raffinose into sugar, but bacteria in the colon love to munch on raffinose and turn it into a lovely gas called methane. This will not only make you unpopular at parties, but can slow digestion and cause significant bloating and discomfort, as well.
Legumes: Legumes are beans and pod vegetables, including soy, lentils, green beans, peas, and garbanzo beans. There are two main reasons why these foods are hard to digest. One is that they contain lots of raffinose (see #3), and the other is that they contain high amounts of soluble fiber. Soluble fiber acts like a sponge in the digestive tract—it absorbs water and swells into a big sticky gel that can form a large, lovely CLOG. Soluble fiber cannot be digested except by bacteria in the colon, so it also eventually forms delightful gases.
Nuts and seeds: Nuts are very closely related to legumes. They are both types of seeds, and therefore contain similar compounds, namely indigestible short-chain carbohydrates and soluble fiber. All seeds also contain enzyme inhibitors which interfere with our ability to digest the proteins within these foods. These inhibitors are damaged or destroyed by cooking, but we often do not cook nuts before eating them. This may be why some people find nuts even more difficult to digest than legumes, which are always thoroughly cooked before eating.
The above are just the most likely suspects in constipation, but keep in mind that everyone is different, and these are not the only foods that can cause problems for people. In my clinical experience I have had patients tell me that lots of other foods can be problematic, including raw vegetables of all kinds (especially the tough, fibrous vegetables like carrots), gelatin (especially if very concentrated, such as in gummi candies), and certain fruits high in pectin and insoluble fiber, such as apples and bananas.
If you have noticed any connection between the foods you eat and your symptoms and you’d like to share your experience, please leave a comment below so that we can all learn from one another.
It is actually easier to define which carbohydrates are NOT refined, because the term “refined” is very confusing. ALL sugars and starches, EXCEPT those that come in the form of a natural whole food like a piece of fruit, a Lima bean, or a sweet potato, are considered refined carbohydrates. If you are looking at a sweet or starchy whole food that you could discover exactly as is in nature, you are looking at an UNrefined carbohydrate.
Refined carbohydrates are forms of sugars and starches that don’t exist in nature. They do come from natural whole foods but they have been altered (processed) in some way to “refine” them. Processing methods include industrial extraction, concentration, purification, and enzymatic transformation. It’s easy for most of us to identify sugars, because they taste sweet and usually come in the form of crystals, syrups, or powders. Refined starches such as refined grains, on the other hand, are a lot more confusing.
What are refined grains?
Truly whole grains are intact kernels (seeds) complete with their outer bran coating just as it is found in nature. Once the grain is broken into pieces by any kind of processing, it has been refined to some extent. The more finely a grain is ground, the tinier the particles. The tinier the particles, the more refined a grain is. The confusion about what constitutes a “refined” grain comes about because processing methods vary. Some (such as stone-grinding) produce large, coarse particles, whereas industrial refining produces ultra-fine powders with all of the fiber and most other nutrients stripped away. Coarse stone-ground grain meals and cracked kernel grains are among the least refined and soft, powdered grains (flours of all kinds and starches such as corn starch) are the most refined.
Particle size matters because the smaller the particles, the easier they are to digest. The easier they are to digest, the faster your blood sugar will rise after you eat them.
To make matters more confusing, there are some forms of grain processing that don’t involve grinding at all. Examples include polishing, high-heat treatment, and extrusion puffing. All of these processes damage or remove the bran coating of grains, making the grains faster to cook and the starches inside easier to digest.
How do refined carbohydrates impact your health?
On my carbohydrates page I mention “the carbohydrate hypothesis of disease.” This is the idea that most diseases of civilization are caused by our so-called “Western” diet, and that the ingredient in the Western diet that is most dangerous is refined carbohydrate. I have written extensively on this site and on my Psychology Today blog about the role of refined carbohydrate on specific medical conditions, including:
To learn more about the health risks associated with eating refined carbohydrates and added sugars, along with a helpful infographic listing simple ways to reduce your risk, please see my post “How to Diagnose, Prevent and Treat Insulin Resistance.“
Okay, enough already, on with the lists!
Refined carbohydrate list
Refined and Simple Sugars (often called “added sugars”)
Table sugar/white sugar (aka sucrose; may be cane sugar or beet sugar)
Confectioner’s sugar (powdered white sugar)
Honey (Even though honey exists in nature and isn’t refined, it is a pure sugar that is difficult to obtain in significant quantities without special equipment or risk. Honey affects our health in exactly the same way that other sugars do.)
Agave syrup
Corn syrup and high-fructose corn syrup
Brown sugar
Molasses
Maple syrup
Fructose
Brown rice syrup
Maltose
Glucose syrup
Tapioca syrup
Rice bran syrup
Malt syrup
Dextran
Sorghum
Treacle
Panela
Saccharose
Carob syrup
Dextrose, dextran, dextrin, maltodextrin
Fruit juice concentrates
All fruit juices
except lemon and lime juice. Juicing fruits eliminates the fiber (that fills you up) and leaves only the sugars and water. And most fruit juices require special equipment to produce in significant quantities.
All types of flour
including wheat, oat, legume (pea and bean), rice, and corn flours.100% stoneground, whole meal flours are less refined and not as unhealthy as other types of flours because they are not as finely ground and take longer to digest.
Instant/refined grains
including instant hot cereals like instant oatmeal, white rice, polished rice, and instant rice
Refined starches
such as corn starch, potato starch, modified food starch—essentially any powdered ingredient with the word “starch” in it
Foods high in refined carbohydrate and added sugars
(not meant to be a complete list)
All desserts except whole fruit
Ice cream, sherbet, frozen yogurt, etc.
Most breads
Many crackers (100% stone-ground whole grain crackers are less refined)
Cookies
Cakes
Muffins
Pancakes
Waffles
Pies
Pastries
Candy
Chocolate (dark, milk and white). Baker’s chocolate is unsweetened and is therefore an exception.
Breaded or battered foods
All types of dough (phyllo, pie crust, etc)
Most cereals except for unsweetened, 100% whole grain cereals in which you can see the whole grains in their entirety with the naked eye (unsweetened muesli, rolled oats, or unsweetened puffed grain cereals are good examples)
Most pastas, noodles and couscous
Jello® (sugar-free varieties exist but it’s much healthier to make your own with unsweetened gelatin and fresh fruit)
Jellies, jams and preserves
Bagels
Pretzels
Pizza (because of the flour in the dough)
Puddings and custards
Corn chips
Caramel corn and kettle corn
Most granola bars, power bars, energy bars, etc (unless labelled sugar-free).
Rice wrappers
Tortillas (unless 100% stone-ground whole grain)
Most rice cakes and corn cakes (unless labelled 100% whole grain)
Panko crumbs
Croutons
Fried vegetable snacks like green beans and carrot chips (usually contain added dextrin, a sweet starch)
Ketchup
Honey mustard
Most barbecue sauces
Check labels on salsa, tomato sauces, salad dressings and other jarred/canned sauces for sugar/sweeteners
Sweetened yogurts and other sweetened dairy products
Honey-roasted nuts
Sweetened sodas
Chocolate milk (and other sweetened milks)
Condensed milk
Hot cocoa
Most milk substitutes (almond milk, soy milk, oat milk, etc) because they usually have sugar added–read label first
100% stone-ground wholegrain breads or crackers without sugar added
Unsweetened tomato sauce and other unsweetened, starch-free sauces
Unsweetened salad dressings (most fat-free dressings contain sugar—check labels). Low-sugar options include blue cheese, ranch, full-fat Italian, Greek, Caesar dressings.
Herbs and spices
Oils
Unsweetened vinegars (balsamic vinegar and certain other fruity vinegars can be very sweet—read label for carbohydrate content)
Textured vegetable protein
Seitan
Tempeh
Unsweetened coffee, tea, sparkling water (either plain or with natural flavors or essences added), water
Most red wines, dry white wines, all spirits (whiskey, gin, vodka, etc)
How much carbohydrate should you eat?
It depends on who you are. All of us should avoid refined carbohydrates and added sugars as much as we possibly can. But what about sugars and starches from whole foods, such as fruits, starchy vegetables, and whole grains? About half of all Americans have insulin resistance, which means that we are very sensitive to carbohydrate and should limit all sources of sugars and starches, not just the “bad” carbs. To learn more about which category you fall into, start by taking my quiz “How Carbohydrate-Sensitive Are You?“
Recommended cookbooks that eliminate refined carbs
21 Day Sugar Detox is written by holistic nutritionist Diane Sanfilippo. Every recipe in this fantastic cookbook is free of refined carbohydrates. Most are quite low in natural sugars and starches as well, making them suitable for low-carb diets. Diane provides accurate information, wise guidance, and delicious menu plans that allow for flexibility with respect to grains, legumes, dairy, and carbohydrate quantity.
Powerhouse husband and wife team Melissa and Dallas Hartwig have inspired countless people to eat real food. The Whole 30 is THE classic Paleo beginner’s guide and cookbook, and is chock full of moral support, education, and humor. Every recipe is free of refined carbohydrates, processed foods, grains, legumes, and dairy products. Their plan is designed to last for 30 days but I’d recommend adding a few zeroes to that number.
This brilliantly creative whole foods cookbook is the brainchild of husband and wife team Michelle Tam and Henry Fong, and is designed to be fun for the whole family. All recipes are free of refined carbohydrates, grains, legumes and processed foods, and most are dairy-free. Nom Nom Paleo is a favorite in my household and we use their recipes all the time. You simply MUST try the Slow Cooker Kalua Pig. Yum.
It is actually easier to define which carbohydrates are NOT refined, because the term “refined” is very confusing. ALL sugars and starches, EXCEPT those that come in the form of a natural whole food like a piece of fruit, a Lima bean, or a sweet potato, are considered refined carbohydrates. If you are looking at a sweet or starchy whole food that you could discover exactly as is in nature, you are looking at an UNrefined carbohydrate.
Refined carbohydrates are forms of sugars and starches that don’t exist in nature. They do come from natural whole foods but they have been altered (processed) in some way to “refine” them. Processing methods include industrial extraction, concentration, purification, and enzymatic transformation. It’s easy for most of us to identify sugars, because they taste sweet and usually come in the form of crystals, syrups, or powders. Refined starches such as refined grains, on the other hand, are a lot more confusing.
What are refined grains?
Truly whole grains are intact kernels (seeds) complete with their outer bran coating just as it is found in nature. Once the grain is broken into pieces by any kind of processing, it has been refined to some extent. The more finely a grain is ground, the tinier the particles. The tinier the particles, the more refined a grain is. The confusion about what constitutes a “refined” grain comes about because processing methods vary. Some (such as stone-grinding) produce large, coarse particles, whereas industrial refining produces ultra-fine powders with all of the fiber and most other nutrients stripped away. Coarse stone-ground grain meals and cracked kernel grains are among the least refined and soft, powdered grains (flours of all kinds and starches such as corn starch) are the most refined.
Particle size matters because the smaller the particles, the easier they are to digest. The easier they are to digest, the faster your blood sugar will rise after you eat them.
To make matters more confusing, there are some forms of grain processing that don’t involve grinding at all. Examples include polishing, high-heat treatment, and extrusion puffing. All of these processes damage or remove the bran coating of grains, making the grains faster to cook and the starches inside easier to digest.
How do refined carbohydrates impact your health?
On my carbohydrates page I mention “the carbohydrate hypothesis of disease.” This is the idea that most diseases of civilization are caused by our so-called “Western” diet, and that the ingredient in the Western diet that is most dangerous is refined carbohydrate. I have written extensively on this site and on my Psychology Today blog about the role of refined carbohydrate on specific medical conditions, including:
To learn more about the health risks associated with eating refined carbohydrates and added sugars, along with a helpful infographic listing simple ways to reduce your risk, please see my post “How to Diagnose, Prevent and Treat Insulin Resistance.“
Okay, enough already, on with the lists!
Refined carbohydrate list
Refined and Simple Sugars (often called “added sugars”)
Table sugar/white sugar (aka sucrose; may be cane sugar or beet sugar)
Confectioner’s sugar (powdered white sugar)
Honey (Even though honey exists in nature and isn’t refined, it is a pure sugar that is difficult to obtain in significant quantities without special equipment or risk. Honey affects our health in exactly the same way that other sugars do.)
Agave syrup
Corn syrup and high-fructose corn syrup
Brown sugar
Molasses
Maple syrup
Fructose
Brown rice syrup
Maltose
Glucose syrup
Tapioca syrup
Rice bran syrup
Malt syrup
Dextran
Sorghum
Treacle
Panela
Saccharose
Carob syrup
Dextrose, dextran, dextrin, maltodextrin
Fruit juice concentrates
All fruit juices
except lemon and lime juice. Juicing fruits eliminates the fiber (that fills you up) and leaves only the sugars and water. And most fruit juices require special equipment to produce in significant quantities.
All types of flour
including wheat, oat, legume (pea and bean), rice, and corn flours.100% stoneground, whole meal flours are less refined and not as unhealthy as other types of flours because they are not as finely ground and take longer to digest.
Instant/refined grains
including instant hot cereals like instant oatmeal, white rice, polished rice, and instant rice
Refined starches
such as corn starch, potato starch, modified food starch—essentially any powdered ingredient with the word “starch” in it
Foods high in refined carbohydrate and added sugars
(not meant to be a complete list)
All desserts except whole fruit
Ice cream, sherbet, frozen yogurt, etc.
Most breads
Many crackers (100% stone-ground whole grain crackers are less refined)
Cookies
Cakes
Muffins
Pancakes
Waffles
Pies
Pastries
Candy
Chocolate (dark, milk and white). Baker’s chocolate is unsweetened and is therefore an exception.
Breaded or battered foods
All types of dough (phyllo, pie crust, etc)
Most cereals except for unsweetened, 100% whole grain cereals in which you can see the whole grains in their entirety with the naked eye (unsweetened muesli, rolled oats, or unsweetened puffed grain cereals are good examples)
Most pastas, noodles and couscous
Jello® (sugar-free varieties exist but it’s much healthier to make your own with unsweetened gelatin and fresh fruit)
Jellies, jams and preserves
Bagels
Pretzels
Pizza (because of the flour in the dough)
Puddings and custards
Corn chips
Caramel corn and kettle corn
Most granola bars, power bars, energy bars, etc (unless labelled sugar-free).
Rice wrappers
Tortillas (unless 100% stone-ground whole grain)
Most rice cakes and corn cakes (unless labelled 100% whole grain)
Panko crumbs
Croutons
Fried vegetable snacks like green beans and carrot chips (usually contain added dextrin, a sweet starch)
Ketchup
Honey mustard
Most barbecue sauces
Check labels on salsa, tomato sauces, salad dressings and other jarred/canned sauces for sugar/sweeteners
Sweetened yogurts and other sweetened dairy products
Honey-roasted nuts
Sweetened sodas
Chocolate milk (and other sweetened milks)
Condensed milk
Hot cocoa
Most milk substitutes (almond milk, soy milk, oat milk, etc) because they usually have sugar added–read label first
100% stone-ground wholegrain breads or crackers without sugar added
Unsweetened tomato sauce and other unsweetened, starch-free sauces
Unsweetened salad dressings (most fat-free dressings contain sugar—check labels). Low-sugar options include blue cheese, ranch, full-fat Italian, Greek, Caesar dressings.
Herbs and spices
Oils
Unsweetened vinegars (balsamic vinegar and certain other fruity vinegars can be very sweet—read label for carbohydrate content)
Textured vegetable protein
Seitan
Tempeh
Unsweetened coffee, tea, sparkling water (either plain or with natural flavors or essences added), water
Most red wines, dry white wines, all spirits (whiskey, gin, vodka, etc)
How much carbohydrate should you eat?
It depends on who you are. All of us should avoid refined carbohydrates and added sugars as much as we possibly can. But what about sugars and starches from whole foods, such as fruits, starchy vegetables, and whole grains? About half of all Americans have insulin resistance, which means that we are very sensitive to carbohydrate and should limit all sources of sugars and starches, not just the “bad” carbs. To learn more about which category you fall into, start by taking my quiz “How Carbohydrate-Sensitive Are You?“
Recommended cookbooks that eliminate refined carbs
21 Day Sugar Detox is written by holistic nutritionist Diane Sanfilippo. Every recipe in this fantastic cookbook is free of refined carbohydrates. Most are quite low in natural sugars and starches as well, making them suitable for low-carb diets. Diane provides accurate information, wise guidance, and delicious menu plans that allow for flexibility with respect to grains, legumes, dairy, and carbohydrate quantity.
Powerhouse husband and wife team Melissa and Dallas Hartwig have inspired countless people to eat real food. The Whole 30 is THE classic Paleo beginner’s guide and cookbook, and is chock full of moral support, education, and humor. Every recipe is free of refined carbohydrates, processed foods, grains, legumes, and dairy products. Their plan is designed to last for 30 days but I’d recommend adding a few zeroes to that number.
This brilliantly creative whole foods cookbook is the brainchild of husband and wife team Michelle Tam and Henry Fong, and is designed to be fun for the whole family. All recipes are free of refined carbohydrates, grains, legumes and processed foods, and most are dairy-free. Nom Nom Paleo is a favorite in my household and we use their recipes all the time. You simply MUST try the Slow Cooker Kalua Pig. Yum.
Meat-phobia is sweeping the country, and for good reason. Alarming headlines proclaiming that meat, especially red meat, was put on this planet specifically to kill us, surely deserve our attention. After all, how could all of those big studies conducted by intelligent scientists at prestigious institutions steer us wrong? So, is red meat bad for you?
Even if the research weren’t so compelling, it stands to reason that meat, the staple food of our uncivilized ancestors for nearly two million years, would suddenly be responsible for the lion’s share of diseases of Western civilization, most of which were uncommon to rare until about a hundred years ago. Right?
Myth #1: Red meat causes cancer, death, and worldwide destruction
All of the studies suggesting that red meat increases risk for cancer and death are epidemiological studies, not experiments, and therefore cannot prove cause and effect. They amount to nothing more than (biased) hunches about the underlying reasons for diseases. Furthermore, the epidemiological studies are a mixed bag of positive, negative, and neutral findings, all pointing in different directions.
I also present a detailed analysis of the World Health Organization’s 2015 report claiming that red meat causes cancer in “WHO Says Meat Causes Cancer?“
Yes, charred meats do contain “polycyclic aromatic hydrocarbons” (or PAHs), but did you know that ALL charred foods contain PAHs—even those grilled vegetables we think of as so healthy? It turns out that most of the PAHs we eat come from cereal products, not grilled meats.
Myth #3: Hot dogs are unhealthy because they contain nitrates and nitrites
It is true that nitrates and nitrites have the potential to form carcinogenic compounds within our bodies, but these compounds are everywhere, not just in preserved meats. In fact, did you know that—ounce for ounce—spinach contains at least 30 times more nitrate than hot dogs do? While one could argue that hot dogs are not the healthiest forms of meat, due to processing and added chemicals, the fact that they contain nitrates is not the most important reason to avoid them.
Myth #4: Red meat is higher in cholesterol than chicken or fish
Cholesterol is built into the membrane of every cell of every animal, therefore all muscle meats—red meat, light meat, and white meat—from all kinds of animals—from birds to fish to cows—contain about the same amount of cholesterol per pound. Oh, and by the way, food cholesterol does not cause high blood cholesterol.
Myth #5: Eating too much meat will cause the kidneys to shut down
There is only ONE study suggesting a connection between animal protein intake and kidney disease, and it was an epidemiological study. The vast majority of experimental studies about kidney disease in humans point to refined carbohydrates as the likely culprit.
As far as I can tell, the only way that meat can hurt you is if it is packaged as a live saber-toothed tiger running towards you.
So, despite the fact that meat is the only nutritionally complete food on earth—rich in high quality protein, vitamins and minerals and naturally low in fattening carbohydrates—run! Run for your life. It’s gonna get you 🙂
Meat-phobia is sweeping the country, and for good reason. Alarming headlines proclaiming that meat, especially red meat, was put on this planet specifically to kill us, surely deserve our attention. After all, how could all of those big studies conducted by intelligent scientists at prestigious institutions steer us wrong? So, is red meat bad for you?
Even if the research weren’t so compelling, it stands to reason that meat, the staple food of our uncivilized ancestors for nearly two million years, would suddenly be responsible for the lion’s share of diseases of Western civilization, most of which were uncommon to rare until about a hundred years ago. Right?
Myth #1: Red meat causes cancer, death, and worldwide destruction
All of the studies suggesting that red meat increases risk for cancer and death are epidemiological studies, not experiments, and therefore cannot prove cause and effect. They amount to nothing more than (biased) hunches about the underlying reasons for diseases. Furthermore, the epidemiological studies are a mixed bag of positive, negative, and neutral findings, all pointing in different directions.
I also present a detailed analysis of the World Health Organization’s 2015 report claiming that red meat causes cancer in “WHO Says Meat Causes Cancer?“
Yes, charred meats do contain “polycyclic aromatic hydrocarbons” (or PAHs), but did you know that ALL charred foods contain PAHs—even those grilled vegetables we think of as so healthy? It turns out that most of the PAHs we eat come from cereal products, not grilled meats.
Myth #3: Hot dogs are unhealthy because they contain nitrates and nitrites
It is true that nitrates and nitrites have the potential to form carcinogenic compounds within our bodies, but these compounds are everywhere, not just in preserved meats. In fact, did you know that—ounce for ounce—spinach contains at least 30 times more nitrate than hot dogs do? While one could argue that hot dogs are not the healthiest forms of meat, due to processing and added chemicals, the fact that they contain nitrates is not the most important reason to avoid them.
Myth #4: Red meat is higher in cholesterol than chicken or fish
Cholesterol is built into the membrane of every cell of every animal, therefore all muscle meats—red meat, light meat, and white meat—from all kinds of animals—from birds to fish to cows—contain about the same amount of cholesterol per pound. Oh, and by the way, food cholesterol does not cause high blood cholesterol.
Myth #5: Eating too much meat will cause the kidneys to shut down
There is only ONE study suggesting a connection between animal protein intake and kidney disease, and it was an epidemiological study. The vast majority of experimental studies about kidney disease in humans point to refined carbohydrates as the likely culprit.
As far as I can tell, the only way that meat can hurt you is if it is packaged as a live saber-toothed tiger running towards you.
So, despite the fact that meat is the only nutritionally complete food on earth—rich in high quality protein, vitamins and minerals and naturally low in fattening carbohydrates—run! Run for your life. It’s gonna get you 🙂
Isn’t it interesting how we are told that dairy products are vital to our health and well-being, yet we shouldn’t eat them in their natural, unprocessed form because that would be dangerous to our health?
While there are many reasons to consider limiting the amount of dairy in your diet—from lactose intolerance to acne to dairy allergies/sensitivities—saturated fat content is clearly not one of them.
In fact, there are good reasons to believe that whole milk, full-fat yogurt, cream, and high-fat cheeses may be better for you than their low-fat alternatives.
Reason #1: Saturated fat is not harmful to your health
We and our ancestors have been eating saturated fat for nearly two million years, yet heart disease and other conditions we tend to associate with saturated fat have only been a significant problem for less than a hundred years. In fact, the low-fat diet craze that took hold of us in the 1970s has not improved our health. U.S. heart disease and obesity rates doubled between 1980 and 2000, despite the fact that we reduced our fat intake over that same period of time, eating more and more carbohydrate instead. The belief that saturated fat is unhealthy is dying a slow long-overdue death.
Reason #2: Low-fat and non-fat dairy products are higher in casein
Casein is a very sticky protein in milk that is quite difficult for humans to digest. Milk proteins are designed to nourish baby cows who are outfitted with a special enzyme (rennet) that can break apart casein. Humans do not make rennet, which is one of the reasons why dairy products can cause constipation and other digestive problems.
Reason #3: Low-fat and non-fat dairy products are higher in whey
Whey proteins raise blood insulin levels just as much as pure sugar does. Even though lactose, the sugar that naturally occurs in milk, has a low “glycemic index” and therefore does not raise blood sugar very much, whey proteins trigger big insulin spikes in our systems. Insulin spikes can destabilize blood sugar and hormone levels, lead to carbohydrate cravings, fatigue, mood swings, and obesity.
Reason 4: High-fat dairy products contain less protein
This means that people who have dairy protein sensitivities may tolerate them better. People who have trouble with dairy foods are almost always reacting either to milk carbohydrate (lactose intolerance) or milk proteins (dairy allergy and sensitivity), not to dairy fat. This is why many dairy-sensitive individuals are able to eat butter and heavy cream, which are extremely low in protein.
Reason #5: High-fat dairy products taste better
Fat tends to improve the flavor, digestibility, and absorption of foods. High-fat dairy products are more satisfying, therefore you may find yourself naturally eating less.
Bottom line: The lower the fat content, the higher the protein content
Keep in mind that, regardless of which types of dairy products you may choose to eat, it remains most important to choose unsweetened varieties, since sugar and other refined carbohydrates raise insulin levels and put health at risk in many important ways. Whatever you do, try to avoid non-fat, sweetened dairy products, such as fat-free fruit yogurts or non-fat chocolate milk, since they are essentially big fat insulin spikes in disguise.
For much more information about dairy products and how they affect our health, please see my dairy page.
Isn’t it interesting how we are told that dairy products are vital to our health and well-being, yet we shouldn’t eat them in their natural, unprocessed form because that would be dangerous to our health?
While there are many reasons to consider limiting the amount of dairy in your diet—from lactose intolerance to acne to dairy allergies/sensitivities—saturated fat content is clearly not one of them.
In fact, there are good reasons to believe that whole milk, full-fat yogurt, cream, and high-fat cheeses may be better for you than their low-fat alternatives.
Reason #1: Saturated fat is not harmful to your health
We and our ancestors have been eating saturated fat for nearly two million years, yet heart disease and other conditions we tend to associate with saturated fat have only been a significant problem for less than a hundred years. In fact, the low-fat diet craze that took hold of us in the 1970s has not improved our health. U.S. heart disease and obesity rates doubled between 1980 and 2000, despite the fact that we reduced our fat intake over that same period of time, eating more and more carbohydrate instead. The belief that saturated fat is unhealthy is dying a slow long-overdue death.
Reason #2: Low-fat and non-fat dairy products are higher in casein
Casein is a very sticky protein in milk that is quite difficult for humans to digest. Milk proteins are designed to nourish baby cows who are outfitted with a special enzyme (rennet) that can break apart casein. Humans do not make rennet, which is one of the reasons why dairy products can cause constipation and other digestive problems.
Reason #3: Low-fat and non-fat dairy products are higher in whey
Whey proteins raise blood insulin levels just as much as pure sugar does. Even though lactose, the sugar that naturally occurs in milk, has a low “glycemic index” and therefore does not raise blood sugar very much, whey proteins trigger big insulin spikes in our systems. Insulin spikes can destabilize blood sugar and hormone levels, lead to carbohydrate cravings, fatigue, mood swings, and obesity.
Reason 4: High-fat dairy products contain less protein
This means that people who have dairy protein sensitivities may tolerate them better. People who have trouble with dairy foods are almost always reacting either to milk carbohydrate (lactose intolerance) or milk proteins (dairy allergy and sensitivity), not to dairy fat. This is why many dairy-sensitive individuals are able to eat butter and heavy cream, which are extremely low in protein.
Reason #5: High-fat dairy products taste better
Fat tends to improve the flavor, digestibility, and absorption of foods. High-fat dairy products are more satisfying, therefore you may find yourself naturally eating less.
Bottom line: The lower the fat content, the higher the protein content
Keep in mind that, regardless of which types of dairy products you may choose to eat, it remains most important to choose unsweetened varieties, since sugar and other refined carbohydrates raise insulin levels and put health at risk in many important ways. Whatever you do, try to avoid non-fat, sweetened dairy products, such as fat-free fruit yogurts or non-fat chocolate milk, since they are essentially big fat insulin spikes in disguise.
For much more information about dairy products and how they affect our health, please see my dairy page.
Life is not fair. Some people can get away with eating anything they want without gaining an ounce while the rest of us just look at a pint of ice cream, and begin to expand ’round the middle. All bodies are not created equal, and anyone who tells you otherwise belongs to that lucky first group of people. They don’t understand, because they live a different reality. It’s not their fault. But here’s the good news. It’s also not your fault.
What is the difference between the lucky svelte people and the unlucky doughy people? There may be many factors, of course, but the one that stands head and shoulders above all the others can essentially be boiled down to “carbohydrate sensitivity.” How your body processes sugars and starchesis what determines whether you build fat easily or burn fat easily. Carbohydrate-sensitive people have exaggerated responses to sugars and starches that set the stage for increased appetite, carbohydrate cravings, and very efficient fat storage.
The role of insulin
These reactions are orchestrated by insulin. When you eat carbohydrates, especially refined/high glycemic index carbohydrates, such as sugar, flour, fruit juice, or white potatoes, your blood sugar begins to rise. Then insulin rushes into your bloodstream to bring it back down again. How does it bring it down? Where does all that extra sugar go? First it sends it off to any cells that might need it. Then, insulin tells your body to stop burning fat, and start burning sugar. So, even if you have plenty of extra body fat that you could be burning for energy, sweets and starches get first priority and they will be burned instead. There is no question that blood sugar spikes leading to insulin spikes are the pathway to obesity. It is impossible to burn body fat if your insulin levels are running too high.
Considering the long-term
Carbohydrate sensitivity tends to worsen over the years, as the body’s system for handling sweets and starches gradually wears out. Type 2 diabetes is essentially the final stage of this process—it is your body’s way of telling you that it simply cannot process carbohydrate anymore. If you already have diabetes, the fat lady has sung. But never fear. There are simple things you can do to stop and even reverse this downward spiral of metabolic madness.
First of all, it would be helpful to know whether or not you are on this path already—how do you know if you are at risk for obesity, type 2 diabetes, high blood pressure, heart disease, and all of the other chronic health problems that come along with carbohydrate sensitivity?
Take the quiz to see where you are on the spectrum of carbohydrate sensitivity, and then follow the links for advice about how you can change your diet to change the course of your future.
What does my score mean?
The more YES answers you have, the more likely it is that you are sensitive to carbohydrates (insulin resistant), and the more seriously you should consider cutting back on carbohydrates in your diet.
1 to 5: YELLOW ZONE. Possible mild carbohydrate sensitivity.
6 to 12: ORANGE ZONE. Likely moderate carbohydrate sensitivity.
13 or higher: RED ZONE. Very likely strong carbohydrate sensitivity.
How can I be sure my symptoms are due to carbohydrates?
These symptoms are just a collection of common clues. For more accurate information about your carbohydrate metabolism, you should ask your doctor for an evaluation and request blood tests. These tests can help determine whether or not you are already on the road to diabetes and related health problems. In the final section of this post there’s a link to a list of the latest lab tests and other practical resources to help you prepare for a conversation with your doctor.
There are also other medical conditions which can cause some of the symptoms mentioned in the quiz. This is another important reason to see your health care professional for an evaluation to make sure that your symptoms aren’t due to another health problem, such as a thyroid condition.
If my score is low, is it ok for me to eat sweets and starches?
If your score is zero or in the lower end of the yellow zone, your body probably handles carbohydrates better than most, which means you may be at lower risk for carbohydrate-related diseases. However, we can’t say your risk is zero, because there isn’t enough scientific research available to answer this question.
Also, your score can easily change over time. Our ability to process carbohydrates tends to gradually worsen as we get older. Some people do fine with carbohydrates until they reach a certain age or stage of life—puberty, pregnancy, middle-age, or menopause. This is partly due to natural hormonal changes, but also may be influenced by the amount and type of carbohydrate we eat. So, even if your score is low now, it could rise over time. Choosing healthier forms of carbohydrate from now on may help to keep your score low as you get older, and keep your risk of carbohydrate-related diseases low. If my score is high, do I have to stop eating all carbohydrates in order to feel better?
Not necessarily. Some people with high scores do just fine if they simply avoid sugars, refined carbohydrates, and other foods that rapidly raise blood sugar and insulin levels. [For a complete list of “bad” carbohydrates, please see my refined carbohydrates list.]. Others have to remove almost all forms of carbohydrate to restore their health. Everyone’s metabolism is different.
If your score is in the upper orange zone or in the red zone, you may be at higher risk for carbohydrate-related health problems, including obesity, type 2 diabetes, cancer, heart disease, and fatty liver disease. I don’t want you to be discouraged, though–in fact, I want you to think of a high score as a helpful early warning sign of problems to come. You can improve your metabolism very quickly and greatly reduce your risk simply by reducing your carbohydrate intake! Even if you already have a carbohydrate-related health problem, reducing your carbohydrate intake is the most powerful way to turn things around!
What should I do next?
Regardless of your quiz score, the single most important thing you can do for your health is to reduce the amount of sugar and refined carbohydrates in your diet! It is amazing how quickly the body responds to being fed properly. You can begin improving your metabolism and protecting your health around in just a few weeks!
KNOW YOUR RISK. Learn where you are on the carbohydrate sensitivity/insulin resistance/pre-diabetes spectrum by obtaining a medical evaluation including blood tests. For a free downloadable PDF of lab tests with their target values, a simple formula for estimating your insulin resistance, recommendations for how much carbohydrate you should consume based on your metabolism, and an infographic with tips for making healthier choices and improving your metabolism, see my post “How to Diagnose, Prevent and Treat Insulin Resistance.”
EDUCATE YOURSELF ABOUT SUGAR AND HEALTH. To learn more about the link between insulin resistance (poor carbohydrate metabolism) and serious chronic illness, such as type 2 diabetes, cancer, fatty liver disease, heart disease, obesity, and gout, read my post “Why Sugar Is Bad for You.“
EXPLORE LOWER-CARBOHYDRATE DIETS. To learn more about low-carbohydrate diets, some of the challenges you might encounter, and get some helpful resources, read my post “Ketogenic Diets 101.”
Life is not fair. Some people can get away with eating anything they want without gaining an ounce while the rest of us just look at a pint of ice cream, and begin to expand ’round the middle. All bodies are not created equal, and anyone who tells you otherwise belongs to that lucky first group of people. They don’t understand, because they live a different reality. It’s not their fault. But here’s the good news. It’s also not your fault.
What is the difference between the lucky svelte people and the unlucky doughy people? There may be many factors, of course, but the one that stands head and shoulders above all the others can essentially be boiled down to “carbohydrate sensitivity.” How your body processes sugars and starchesis what determines whether you build fat easily or burn fat easily. Carbohydrate-sensitive people have exaggerated responses to sugars and starches that set the stage for increased appetite, carbohydrate cravings, and very efficient fat storage.
The role of insulin
These reactions are orchestrated by insulin. When you eat carbohydrates, especially refined/high glycemic index carbohydrates, such as sugar, flour, fruit juice, or white potatoes, your blood sugar begins to rise. Then insulin rushes into your bloodstream to bring it back down again. How does it bring it down? Where does all that extra sugar go? First it sends it off to any cells that might need it. Then, insulin tells your body to stop burning fat, and start burning sugar. So, even if you have plenty of extra body fat that you could be burning for energy, sweets and starches get first priority and they will be burned instead. There is no question that blood sugar spikes leading to insulin spikes are the pathway to obesity. It is impossible to burn body fat if your insulin levels are running too high.
Considering the long-term
Carbohydrate sensitivity tends to worsen over the years, as the body’s system for handling sweets and starches gradually wears out. Type 2 diabetes is essentially the final stage of this process—it is your body’s way of telling you that it simply cannot process carbohydrate anymore. If you already have diabetes, the fat lady has sung. But never fear. There are simple things you can do to stop and even reverse this downward spiral of metabolic madness.
First of all, it would be helpful to know whether or not you are on this path already—how do you know if you are at risk for obesity, type 2 diabetes, high blood pressure, heart disease, and all of the other chronic health problems that come along with carbohydrate sensitivity?
Take the quiz to see where you are on the spectrum of carbohydrate sensitivity, and then follow the links for advice about how you can change your diet to change the course of your future.
What does my score mean?
The more YES answers you have, the more likely it is that you are sensitive to carbohydrates (insulin resistant), and the more seriously you should consider cutting back on carbohydrates in your diet.
1 to 5: YELLOW ZONE. Possible mild carbohydrate sensitivity.
6 to 12: ORANGE ZONE. Likely moderate carbohydrate sensitivity.
13 or higher: RED ZONE. Very likely strong carbohydrate sensitivity.
How can I be sure my symptoms are due to carbohydrates?
These symptoms are just a collection of common clues. For more accurate information about your carbohydrate metabolism, you should ask your doctor for an evaluation and request blood tests. These tests can help determine whether or not you are already on the road to diabetes and related health problems. In the final section of this post there’s a link to a list of the latest lab tests and other practical resources to help you prepare for a conversation with your doctor.
There are also other medical conditions which can cause some of the symptoms mentioned in the quiz. This is another important reason to see your health care professional for an evaluation to make sure that your symptoms aren’t due to another health problem, such as a thyroid condition.
If my score is low, is it ok for me to eat sweets and starches?
If your score is zero or in the lower end of the yellow zone, your body probably handles carbohydrates better than most, which means you may be at lower risk for carbohydrate-related diseases. However, we can’t say your risk is zero, because there isn’t enough scientific research available to answer this question.
Also, your score can easily change over time. Our ability to process carbohydrates tends to gradually worsen as we get older. Some people do fine with carbohydrates until they reach a certain age or stage of life—puberty, pregnancy, middle-age, or menopause. This is partly due to natural hormonal changes, but also may be influenced by the amount and type of carbohydrate we eat. So, even if your score is low now, it could rise over time. Choosing healthier forms of carbohydrate from now on may help to keep your score low as you get older, and keep your risk of carbohydrate-related diseases low. If my score is high, do I have to stop eating all carbohydrates in order to feel better?
Not necessarily. Some people with high scores do just fine if they simply avoid sugars, refined carbohydrates, and other foods that rapidly raise blood sugar and insulin levels. [For a complete list of “bad” carbohydrates, please see my refined carbohydrates list.]. Others have to remove almost all forms of carbohydrate to restore their health. Everyone’s metabolism is different.
If your score is in the upper orange zone or in the red zone, you may be at higher risk for carbohydrate-related health problems, including obesity, type 2 diabetes, cancer, heart disease, and fatty liver disease. I don’t want you to be discouraged, though–in fact, I want you to think of a high score as a helpful early warning sign of problems to come. You can improve your metabolism very quickly and greatly reduce your risk simply by reducing your carbohydrate intake! Even if you already have a carbohydrate-related health problem, reducing your carbohydrate intake is the most powerful way to turn things around!
What should I do next?
Regardless of your quiz score, the single most important thing you can do for your health is to reduce the amount of sugar and refined carbohydrates in your diet! It is amazing how quickly the body responds to being fed properly. You can begin improving your metabolism and protecting your health around in just a few weeks!
KNOW YOUR RISK. Learn where you are on the carbohydrate sensitivity/insulin resistance/pre-diabetes spectrum by obtaining a medical evaluation including blood tests. For a free downloadable PDF of lab tests with their target values, a simple formula for estimating your insulin resistance, recommendations for how much carbohydrate you should consume based on your metabolism, and an infographic with tips for making healthier choices and improving your metabolism, see my post “How to Diagnose, Prevent and Treat Insulin Resistance.”
EDUCATE YOURSELF ABOUT SUGAR AND HEALTH. To learn more about the link between insulin resistance (poor carbohydrate metabolism) and serious chronic illness, such as type 2 diabetes, cancer, fatty liver disease, heart disease, obesity, and gout, read my post “Why Sugar Is Bad for You.“
EXPLORE LOWER-CARBOHYDRATE DIETS. To learn more about low-carbohydrate diets, some of the challenges you might encounter, and get some helpful resources, read my post “Ketogenic Diets 101.”
The word fiber conjures up wholesome, earthy-crunchy images of squeaky clean intestines and free-flowing coronary arteries. Yet fiber is not a nutrient at all, and is not absorbed by our bodies. What is fiber? What is the difference between soluble and insoluble fiber, is it really healthy for us, and do we even need to eat it?
What is fiber?
Fiber comes from the cell walls of plants. It provides shape and architectural support to the plant. Animals do not contain any fiber; we use bone and cartilage to support our bodies instead. Fiber is by definition indigestible by humans.
There are two types of fiber: soluble and insoluble. All plant foods (fruits, vegetables, nuts, beans, seeds and grains) contain a combination of soluble and insoluble fiber in varying amounts. We are told that soluble fiber is good for us because it slows things down and we are told that insoluble fiber is good for us because it speeds things up. Hmmm . . .
Insoluble fiber: the tough stuff
Insoluble fiber is affectionately called “roughage.” Insoluble fiber is called insoluble because it does not dissolve in water. It is the stuff that gives tree bark, nutshells and twigs their woody texture. Foods high in insoluble fiber include grains, seeds, nuts, vegetables and certain fruits. Insoluble fibers pass through our digestive system practically untouched, because even bacteria can’t easily digest them. We are told that insoluble fiber is good for us because it adds weighty “bulk” to the contents of our intestines, helping to push things along. Why expose the smooth inner surfaces of our intestines to these abrasive indigestibles? We are told that we need them to sweep our innards clean of potential toxins. Oddly enough, I was unable to locate a single scientific article explaining what these toxins are and how insoluble fiber removes them . . . therefore this must simply be a common belief—an appealing image that makes sense in our minds, but that has absolutely no science behind it.
Soluble Fiber: the swell gel
The biggest difference between soluble fiber and insoluble fiber is that it is, as the name implies, soluble in water—it can partially dissolve in water. Most over-the-counter laxatives are made with soluble fiber. Soluble fiber dissolves partially in water, forming a gel—you can see this happen when you stir a soluble fiber supplement such as Metamucil® into a glass of water. The ability of soluble fiber to hold water is what allows fruits and soft vegetable parts to contain water and yet maintain their firm shape.
The soluble fiber family includes a wide variety of plant compounds such as arabinoxylan, dextrins, inulin, waxes, chitins, pectins, and beta-glucan. Soluble fiber is found in apples and pears, oats, pitted fruits, psyllium, citrus fruits, beans, berries, and brussels sprouts, among other foods. Some types of soluble fiber are more “viscous” than others, meaning they form firmer, stickier gels. We are told that this swollen gel action is good for us for three reasons:
Viscous soluble fiber binds some of the LDL or so-called “bad cholesterol” we eat so that less of it enters our bloodstream.
Gels move more slowly through the intestine than liquids. When we eat something sweet along with soluble fiber, the gel will slow down the absorption of sugar into the bloodstream, which may reduce blood sugar spiking.
The swollen gel helps us to feel full, so we may eat less food.
These are all good things, right? Don’t we want to feel full, and lower our cholesterol and blood sugar levels? Yes, of course we do! So let’s take a look at each of these claims.
Does fiber lower cholesterol levels?
Yes. A recent review of studies on the effect of plant-based diets on cholesterol levels showed a maximum reduction in LDL cholesterol of about one-third [Mente 2009]. This is why fiber is advertised as “heart healthy.” Of course, if you’ve read the cholesterol page you know that a) LDL is not necessarily bad, and b) the most powerful way to improve your cholesterol profile is to eat a low-glycemic-index or low-carbohydrate diet.
Can fiber lower blood sugar?
Yes. Soluble fiber has been definitively shown to reduce the glycemic index (the degree to which your blood sugar will spike) of sweet or starchy foods, but only by 10 to 20% [Melanson 2006]. This is probably because fiber slows digestion of carbohydrates by interfering with normal digestion. Of course, a much more powerful and direct way to reduce the glycemic index of the foods you eat is to . . . avoid high-glycemic-index foods.
Do high-fiber diets help with weight loss?
No. Most studies show little to no weight loss benefit, but study results were mixed and many studies were poorly designed. According to Nutrition Reviews:
“the limited number of clinical trials comparing high-fiber foods with low-fiber foods have not provided consistent data indicating that these diets are more efficacious for weight loss than low-fiber control diets.”
An interesting analysis of twenty different studies of the use of guar gum (a soluble fiber supplement) in weight loss noted that the guar gum caused abdominal pain, flatulence, diarrhea and cramps, and concluded that:
“guar gum is not efficacious for reducing body weight. Considering the adverse events associated with its use, the risks of taking guar gum outweigh its benefits for this indication. Therefore, guar gum cannot be recommended as a treatment for lowering body weight.”
Fiber and colon health
Does fiber protect the colon from cancer, constipation, and other diseases?
No. In the World Journal of Gastroenterology in 2007, Doctors Tan and Seow-Choen published a review of medical studies conducted over the previous 35 years about fiber and colon health and concluded:
“A strong case cannot be made for a protective effect of dietary fiber against colorectal polyp or cancer. Neither has fiber been found to be useful in chronic constipation and irritable bowel syndrome. It is also not useful in the treatment of perianal conditions. The fiber deficit-diverticulosis theory should also be challenged…we often choose to believe a lie, as a lie repeated often enough by enough people becomes accepted as the truth. We urge clinicians to keep an open mind. Myths about fiber must be debunked and truth installed.”
Ok, so if you are eating a diet that includes high glycemic and refined carbohydrates, soluble (gel) fiber will probably not help you lose weight, but it may soften your blood sugar spikes, and may lower your cholesterol a little. So, since fiber can be helpful in reducing the risks associated with eating a high carbohydrate diet, is there any reason NOT to eat it?
Bacteria love soluble fiber
We cannot digest the carbohydrates that make up soluble fiber, but the bacteria in our large intestine can, and they do. Undigested carbohydrate fibers arriving in the colon attract huge numbers of bacteria for a free lunch. Is there anything wrong with that? Why not let them enjoy themselves? Well, bacteria don’t exactly digest these carbohydrates, they ferment them, and in the process, they give off gases, like carbon dioxide, hydrogen, and methane. Not only can these gases make you unpopular at parties, but they can also cause uncomfortable cramping and bloating, both common sense signs of poor digestion.
Listen to your body: good digestion should not hurt. Yes, you may feel like eating less, but it’s only because soluble fiber swells within your system, attracting a swarm of bacteria, which ferment the fiber and generate a balloon of gases, creating a feeling of fullness. In contrast, animal protein and fat are comfortably and efficiently digested by humans with virtually no gases produced.
Soluble fiber extracts are like greedy sponges
Once trapped inside of you they require LOTS of water to form the sticky ooze that is supposed to be so good for us. A friend of mine recently told me the story of how she discovered an old container of Metamucil® in the back of her refrigerator that she innocently tried to dispose of by pouring it down the sink. Unfortunately, when she started the water running to flush it down the drain, the psyllium fibers rapidly expanded into a huge, stubborn, constipating blob that her plumber could only dislodge by physically dismantling the pipes.
Word to the wise: if you do not drink lots of water along with your soluble fiber supplement, you, too, could find yourself in need of some expensive professional assistance. We were not meant to swallow concentrated extracts of plant fiber. We were designed to eat whole foods. This is why Mother Nature designed juicy, appealing fruits complete with their own water supply.
Why do experts believe that fiber is essential for health?
It is a simple misunderstanding of the research. Well-meaning, intelligent scientists looked at all the data and came to the wrong conclusion by making a single, critically flawed assumption that led them in the wrong direction. About 150 years ago, the world was populated by two kinds of people: people who were still eating “traditional” diets of various types, and people who were starting to eat a “modern” diet.
For the full description of the history and politics of the development of the false fiber theory, I recommend reading the chapter on fiber in Gary Taubes’ Good Calories Bad Calories.
The traditional diet folks were eating all sorts of things, depending on where they lived, so their diets varied tremendously from one culture to another. Some ate mostly meat. Some ate meat, and dairy products. Some ate poultry, grains, and vegetables. Some ate fish, coconuts, and fruit. All of these traditional people were incredibly healthy compared to us—all of them enjoyed extremely low rates of cancer; were virtually free of heart disease, diabetes and obesity; sported strong teeth and bones; and had normal blood pressures.
The modern diet folks were also eating all sorts of things, depending on where they lived, so their diets also varied tremendously from one culture to another. They also ate some combination of meats, fish, nuts, fruits, vegetables and grains, but what set them apart from the traditional people and what made their diets “modern” was the addition of highly-refined flours and large amounts of sugar. In the 1870s, advances in modern milling technology saw stone grinding wheels replaced with steel rollers, capable of stripping the bran and wheat germ away from the soft center of each grain. This process resulted in the ability to produce ultra-fine, 100% fiber-free particles—the most refined flour in human history. Modern societies had also devised more efficient and less expensive ways to cultivate and distribute sugar to large numbers of people who previously could not afford to buy it.
Time after time, when the health of a traditional culture was compared to the health of a modern culture, the traditional culture came out on top, so it was clear to researchers that modern diets were unhealthy. The problem was that some scientists looked at these two types of diets and jumped to the wrong conclusion about why modern diets were inferior to traditional diets. They assumed it was because modern diets were lacking in fiber, not because modern diets were loaded with refined carbohydrates.
Now, it is absolutely true that modern diets contained far less fiber than traditional diets did, so they were not wrong about that. Traditional peoples who ate grains ate them whole, stone-ground, or cultured—all forms of grains that have not had their fiber stripped away. However, study after study has shown that adding fiber back to our modern diet does not restore us to the excellent health our ancestors enjoyed. Thus simply eating more fiber in our diet is not the answer.
I have yet to see a single scientific study demonstrating that fiber solves any of our problems. At worst, fiber causes constipation, irritation and damage to the inner lining of the intestine, flatulence and pain. At best, fiber reduces blood sugar spikes by ten to twenty percent, reduces LDL cholesterol by about one-third, and promotes a “feeling of fullness”. If you are eating a diet that contains more than a small percentage of sugar and refined carbohydrates, you could eat a truckload of oat bran and still never see your blood sugar, cholesterol level or appetite come down to normal and stay there.
Here is an example of the kinds of studies that have been done to show that fiber is healthy:
“Whole-grain ready-to-eat oat cereal, as part of a dietary program for weight loss, reduces low-density lipoprotein cholesterol in adults with overweight and obesity more than a dietary program including low-fiber control foods.” [Maki 2010]
Sounds promising, until you read the study and learn that there was no difference in weight between the two groups after twelve weeks, that LDL only decreased by about five percent, and waist circumference only decreased by about a half-inch. You read further and discover that the “low-fiber control foods” were refined-carbohydrate junk foods:
“participants were randomly assigned to consume either two portions/day (3 c/day) of whole-grain ready-to-eat oat cereal (providing 3 g/day b-glucan) or low-fiber breakfast/snack foods (eg, ready-to-eat corn cereals, white toast, plain bagels and English muffins, pretzels, soda crackers, or rice cakes) with a similar energy and macronutrient content (control group).”
It would not be surprising that oat cereal is (perhaps, a tiny bit) healthier than white toast, plain bagels, English muffins and pretzels! However, it is impossible to conclude that the oat cereal was beneficial—it is just as likely that the reason for the very modest benefits seen in the oat cereal eaters was not that they were eating more fiber than the comparison group, but that they were eating fewer refined carbohydrates (sugars and flours) than the comparison group. Or it may be that oats are not as bad for you as wheat and corn. To make matters worse, three of the study’s authors were scientists who worked for General Mills, the manufacturer of Cheerios, the oat cereal used in the experiment! Coming soon to a commercial near you . . .
To fiber or not to fiber. . .
When you think about it logically, if you wanted to figure out whether or not a particular food is good for humans, you would want to design the study exactly that way—one diet WITH the food and one diet WITHOUT the food. The only study I know of that has dared to completely remove fiber from the human diet yielded remarkable results.
In 2012, a randomized controlled trial of 63 people with chronic constipation was conducted in which all participants were placed on a fiber-free diet for two weeks, then were allowed to eat any diet they wished for the next six months. At six months, 41 people were still voluntarily following the fiber-free diet because they had all experienced 100% relief from their symptoms, whereas 100% of those who had gone back to eating fiber continued to suffer from IBS symptoms [Ho 2012].
Cardboard: yes. Delicious: no.
If you still aren’t convinced that we are not designed to require fiber, I have no choice but to appeal to your good judgment and common sense. Pour yourself a nice big bowl of wheat bran, grab a spoon and dig in. I don’t mean a bowl of sweetened bran cereal with milk or yogurt or berries on top, I mean a bowl of 100% unsweetened wheat bran. Does it look or smell or taste good to you? Do you like it? Do your kids like it? Can you swallow it?
We want to believe in the power of fiber. It is so much easier and so much more appealing to contemplate adding fiber, which is tasteless and indigestible, than to contemplate subtracting refined carbohydrates, which are addictively delicious and fun to eat.
Adding fiber to your diet cannot cure any health problem, because it doesn’t get to the root of the problem.
If you eat risky refined and high glycemic index carbohydrates regularly, soluble fiber may soften your blood sugar (and insulin) spikes and may reduce your cholesterol a little by interfering with their digestion.
If you find soluble fiber supplements useful, take care to drink plenty of water with them.
If fiber bothers your digestive system, or you don’t like eating it, you can safely avoid it, since it is not essential to your health.
The word fiber conjures up wholesome, earthy-crunchy images of squeaky clean intestines and free-flowing coronary arteries. Yet fiber is not a nutrient at all, and is not absorbed by our bodies. What is fiber? What is the difference between soluble and insoluble fiber, is it really healthy for us, and do we even need to eat it?
What is fiber?
Fiber comes from the cell walls of plants. It provides shape and architectural support to the plant. Animals do not contain any fiber; we use bone and cartilage to support our bodies instead. Fiber is by definition indigestible by humans.
There are two types of fiber: soluble and insoluble. All plant foods (fruits, vegetables, nuts, beans, seeds and grains) contain a combination of soluble and insoluble fiber in varying amounts. We are told that soluble fiber is good for us because it slows things down and we are told that insoluble fiber is good for us because it speeds things up. Hmmm . . .
Insoluble fiber: the tough stuff
Insoluble fiber is affectionately called “roughage.” Insoluble fiber is called insoluble because it does not dissolve in water. It is the stuff that gives tree bark, nutshells and twigs their woody texture. Foods high in insoluble fiber include grains, seeds, nuts, vegetables and certain fruits. Insoluble fibers pass through our digestive system practically untouched, because even bacteria can’t easily digest them. We are told that insoluble fiber is good for us because it adds weighty “bulk” to the contents of our intestines, helping to push things along. Why expose the smooth inner surfaces of our intestines to these abrasive indigestibles? We are told that we need them to sweep our innards clean of potential toxins. Oddly enough, I was unable to locate a single scientific article explaining what these toxins are and how insoluble fiber removes them . . . therefore this must simply be a common belief—an appealing image that makes sense in our minds, but that has absolutely no science behind it.
Soluble Fiber: the swell gel
The biggest difference between soluble fiber and insoluble fiber is that it is, as the name implies, soluble in water—it can partially dissolve in water. Most over-the-counter laxatives are made with soluble fiber. Soluble fiber dissolves partially in water, forming a gel—you can see this happen when you stir a soluble fiber supplement such as Metamucil® into a glass of water. The ability of soluble fiber to hold water is what allows fruits and soft vegetable parts to contain water and yet maintain their firm shape.
The soluble fiber family includes a wide variety of plant compounds such as arabinoxylan, dextrins, inulin, waxes, chitins, pectins, and beta-glucan. Soluble fiber is found in apples and pears, oats, pitted fruits, psyllium, citrus fruits, beans, berries, and brussels sprouts, among other foods. Some types of soluble fiber are more “viscous” than others, meaning they form firmer, stickier gels. We are told that this swollen gel action is good for us for three reasons:
Viscous soluble fiber binds some of the LDL or so-called “bad cholesterol” we eat so that less of it enters our bloodstream.
Gels move more slowly through the intestine than liquids. When we eat something sweet along with soluble fiber, the gel will slow down the absorption of sugar into the bloodstream, which may reduce blood sugar spiking.
The swollen gel helps us to feel full, so we may eat less food.
These are all good things, right? Don’t we want to feel full, and lower our cholesterol and blood sugar levels? Yes, of course we do! So let’s take a look at each of these claims.
Does fiber lower cholesterol levels?
Yes. A recent review of studies on the effect of plant-based diets on cholesterol levels showed a maximum reduction in LDL cholesterol of about one-third [Mente 2009]. This is why fiber is advertised as “heart healthy.” Of course, if you’ve read the cholesterol page you know that a) LDL is not necessarily bad, and b) the most powerful way to improve your cholesterol profile is to eat a low-glycemic-index or low-carbohydrate diet.
Can fiber lower blood sugar?
Yes. Soluble fiber has been definitively shown to reduce the glycemic index (the degree to which your blood sugar will spike) of sweet or starchy foods, but only by 10 to 20% [Melanson 2006]. This is probably because fiber slows digestion of carbohydrates by interfering with normal digestion. Of course, a much more powerful and direct way to reduce the glycemic index of the foods you eat is to . . . avoid high-glycemic-index foods.
Do high-fiber diets help with weight loss?
No. Most studies show little to no weight loss benefit, but study results were mixed and many studies were poorly designed. According to Nutrition Reviews:
“the limited number of clinical trials comparing high-fiber foods with low-fiber foods have not provided consistent data indicating that these diets are more efficacious for weight loss than low-fiber control diets.”
An interesting analysis of twenty different studies of the use of guar gum (a soluble fiber supplement) in weight loss noted that the guar gum caused abdominal pain, flatulence, diarrhea and cramps, and concluded that:
“guar gum is not efficacious for reducing body weight. Considering the adverse events associated with its use, the risks of taking guar gum outweigh its benefits for this indication. Therefore, guar gum cannot be recommended as a treatment for lowering body weight.”
Fiber and colon health
Does fiber protect the colon from cancer, constipation, and other diseases?
No. In the World Journal of Gastroenterology in 2007, Doctors Tan and Seow-Choen published a review of medical studies conducted over the previous 35 years about fiber and colon health and concluded:
“A strong case cannot be made for a protective effect of dietary fiber against colorectal polyp or cancer. Neither has fiber been found to be useful in chronic constipation and irritable bowel syndrome. It is also not useful in the treatment of perianal conditions. The fiber deficit-diverticulosis theory should also be challenged…we often choose to believe a lie, as a lie repeated often enough by enough people becomes accepted as the truth. We urge clinicians to keep an open mind. Myths about fiber must be debunked and truth installed.”
Ok, so if you are eating a diet that includes high glycemic and refined carbohydrates, soluble (gel) fiber will probably not help you lose weight, but it may soften your blood sugar spikes, and may lower your cholesterol a little. So, since fiber can be helpful in reducing the risks associated with eating a high carbohydrate diet, is there any reason NOT to eat it?
Bacteria love soluble fiber
We cannot digest the carbohydrates that make up soluble fiber, but the bacteria in our large intestine can, and they do. Undigested carbohydrate fibers arriving in the colon attract huge numbers of bacteria for a free lunch. Is there anything wrong with that? Why not let them enjoy themselves? Well, bacteria don’t exactly digest these carbohydrates, they ferment them, and in the process, they give off gases, like carbon dioxide, hydrogen, and methane. Not only can these gases make you unpopular at parties, but they can also cause uncomfortable cramping and bloating, both common sense signs of poor digestion.
Listen to your body: good digestion should not hurt. Yes, you may feel like eating less, but it’s only because soluble fiber swells within your system, attracting a swarm of bacteria, which ferment the fiber and generate a balloon of gases, creating a feeling of fullness. In contrast, animal protein and fat are comfortably and efficiently digested by humans with virtually no gases produced.
Soluble fiber extracts are like greedy sponges
Once trapped inside of you they require LOTS of water to form the sticky ooze that is supposed to be so good for us. A friend of mine recently told me the story of how she discovered an old container of Metamucil® in the back of her refrigerator that she innocently tried to dispose of by pouring it down the sink. Unfortunately, when she started the water running to flush it down the drain, the psyllium fibers rapidly expanded into a huge, stubborn, constipating blob that her plumber could only dislodge by physically dismantling the pipes.
Word to the wise: if you do not drink lots of water along with your soluble fiber supplement, you, too, could find yourself in need of some expensive professional assistance. We were not meant to swallow concentrated extracts of plant fiber. We were designed to eat whole foods. This is why Mother Nature designed juicy, appealing fruits complete with their own water supply.
Why do experts believe that fiber is essential for health?
It is a simple misunderstanding of the research. Well-meaning, intelligent scientists looked at all the data and came to the wrong conclusion by making a single, critically flawed assumption that led them in the wrong direction. About 150 years ago, the world was populated by two kinds of people: people who were still eating “traditional” diets of various types, and people who were starting to eat a “modern” diet.
For the full description of the history and politics of the development of the false fiber theory, I recommend reading the chapter on fiber in Gary Taubes’ Good Calories Bad Calories.
The traditional diet folks were eating all sorts of things, depending on where they lived, so their diets varied tremendously from one culture to another. Some ate mostly meat. Some ate meat, and dairy products. Some ate poultry, grains, and vegetables. Some ate fish, coconuts, and fruit. All of these traditional people were incredibly healthy compared to us—all of them enjoyed extremely low rates of cancer; were virtually free of heart disease, diabetes and obesity; sported strong teeth and bones; and had normal blood pressures.
The modern diet folks were also eating all sorts of things, depending on where they lived, so their diets also varied tremendously from one culture to another. They also ate some combination of meats, fish, nuts, fruits, vegetables and grains, but what set them apart from the traditional people and what made their diets “modern” was the addition of highly-refined flours and large amounts of sugar. In the 1870s, advances in modern milling technology saw stone grinding wheels replaced with steel rollers, capable of stripping the bran and wheat germ away from the soft center of each grain. This process resulted in the ability to produce ultra-fine, 100% fiber-free particles—the most refined flour in human history. Modern societies had also devised more efficient and less expensive ways to cultivate and distribute sugar to large numbers of people who previously could not afford to buy it.
Time after time, when the health of a traditional culture was compared to the health of a modern culture, the traditional culture came out on top, so it was clear to researchers that modern diets were unhealthy. The problem was that some scientists looked at these two types of diets and jumped to the wrong conclusion about why modern diets were inferior to traditional diets. They assumed it was because modern diets were lacking in fiber, not because modern diets were loaded with refined carbohydrates.
Now, it is absolutely true that modern diets contained far less fiber than traditional diets did, so they were not wrong about that. Traditional peoples who ate grains ate them whole, stone-ground, or cultured—all forms of grains that have not had their fiber stripped away. However, study after study has shown that adding fiber back to our modern diet does not restore us to the excellent health our ancestors enjoyed. Thus simply eating more fiber in our diet is not the answer.
I have yet to see a single scientific study demonstrating that fiber solves any of our problems. At worst, fiber causes constipation, irritation and damage to the inner lining of the intestine, flatulence and pain. At best, fiber reduces blood sugar spikes by ten to twenty percent, reduces LDL cholesterol by about one-third, and promotes a “feeling of fullness”. If you are eating a diet that contains more than a small percentage of sugar and refined carbohydrates, you could eat a truckload of oat bran and still never see your blood sugar, cholesterol level or appetite come down to normal and stay there.
Here is an example of the kinds of studies that have been done to show that fiber is healthy:
“Whole-grain ready-to-eat oat cereal, as part of a dietary program for weight loss, reduces low-density lipoprotein cholesterol in adults with overweight and obesity more than a dietary program including low-fiber control foods.” [Maki 2010]
Sounds promising, until you read the study and learn that there was no difference in weight between the two groups after twelve weeks, that LDL only decreased by about five percent, and waist circumference only decreased by about a half-inch. You read further and discover that the “low-fiber control foods” were refined-carbohydrate junk foods:
“participants were randomly assigned to consume either two portions/day (3 c/day) of whole-grain ready-to-eat oat cereal (providing 3 g/day b-glucan) or low-fiber breakfast/snack foods (eg, ready-to-eat corn cereals, white toast, plain bagels and English muffins, pretzels, soda crackers, or rice cakes) with a similar energy and macronutrient content (control group).”
It would not be surprising that oat cereal is (perhaps, a tiny bit) healthier than white toast, plain bagels, English muffins and pretzels! However, it is impossible to conclude that the oat cereal was beneficial—it is just as likely that the reason for the very modest benefits seen in the oat cereal eaters was not that they were eating more fiber than the comparison group, but that they were eating fewer refined carbohydrates (sugars and flours) than the comparison group. Or it may be that oats are not as bad for you as wheat and corn. To make matters worse, three of the study’s authors were scientists who worked for General Mills, the manufacturer of Cheerios, the oat cereal used in the experiment! Coming soon to a commercial near you . . .
To fiber or not to fiber. . .
When you think about it logically, if you wanted to figure out whether or not a particular food is good for humans, you would want to design the study exactly that way—one diet WITH the food and one diet WITHOUT the food. The only study I know of that has dared to completely remove fiber from the human diet yielded remarkable results.
In 2012, a randomized controlled trial of 63 people with chronic constipation was conducted in which all participants were placed on a fiber-free diet for two weeks, then were allowed to eat any diet they wished for the next six months. At six months, 41 people were still voluntarily following the fiber-free diet because they had all experienced 100% relief from their symptoms, whereas 100% of those who had gone back to eating fiber continued to suffer from IBS symptoms [Ho 2012].
Cardboard: yes. Delicious: no.
If you still aren’t convinced that we are not designed to require fiber, I have no choice but to appeal to your good judgment and common sense. Pour yourself a nice big bowl of wheat bran, grab a spoon and dig in. I don’t mean a bowl of sweetened bran cereal with milk or yogurt or berries on top, I mean a bowl of 100% unsweetened wheat bran. Does it look or smell or taste good to you? Do you like it? Do your kids like it? Can you swallow it?
We want to believe in the power of fiber. It is so much easier and so much more appealing to contemplate adding fiber, which is tasteless and indigestible, than to contemplate subtracting refined carbohydrates, which are addictively delicious and fun to eat.
Adding fiber to your diet cannot cure any health problem, because it doesn’t get to the root of the problem.
If you eat risky refined and high glycemic index carbohydrates regularly, soluble fiber may soften your blood sugar (and insulin) spikes and may reduce your cholesterol a little by interfering with their digestion.
If you find soluble fiber supplements useful, take care to drink plenty of water with them.
If fiber bothers your digestive system, or you don’t like eating it, you can safely avoid it, since it is not essential to your health.
We are told that vegetables are powerful and virtuous—that they fight off cancer, sweep our digestive systems clean, and strengthen our immune system—that they can leap tall buildings in a single bound. Yet vegetables have a dark side. They don’t want to be eaten any more than animals do, and use sophisticated chemical weapons to defend themselves . . .
Vegetable psychology
We think of them as virtuous, vital components of a healthy diet . . . yet vegetables are cunning and manipulative.
Deep down they don’t care about us. Our health is not their top priority; their top priority is their own survival. Plants have been on earth for hundreds of millions of years and they have learned a thing or two about survival.
Pretend you are a plant:
You can’t run away from animals that stop to dine on you. You can’t growl to scare predators away. You can’t wander around to meet other plants and reproduce. You can’t brush off caterpillars that are nibbling on you. You can’t swat away the insects that stop to bite you.
How do you protect yourself?
Well, you might have thorns or other special structures to help deter some invaders, but mostly you use chemical weapons . . . and very sophisticated ones, at that. Plants have been on this planet a lot longer than we have and they’ve got our number. They know what we like and don’t like. They know how our cells work. They know our strengths and weaknesses.
They have gone out of their way to make some vegetable parts taste bitter, so that we are less likely to want to eat them. In fact, the produce industry has had to work hard to breed bitterness out of vegetables so that we will be more likely to buy them. These bitter substances not only taste bad, they also function as highly specialized pesticides that are designed to kill insects, larvae, worms, bacteria, and fungi. These include things like:
Specialized immune system molecules that recognize invaders, attach to them, and mark them for the kill.
Poisons that kill cells and mitochondria by bursting their membranes open.
Enzyme inhibitors that interfere with vital metabolic reactions.
Oxidative toxins that break DNA strands
Because we believe that vegetables are good for us, we spend lots of time, energy, and money trying to prove how these bitter pesticides might be beneficial to human health. Because many of these same chemicals function as “antioxidants” in the laboratory, scientists enjoy studying how they might be used to fight cancer and other diseases.
Fair enough, but wouldn’t it make sense to also wonder whether these chemicals might be harmful to us?
What are vegetables?
Vegetables are any plant parts that are not fruits, seeds, or flowers. Vegetable parts include roots, tubers, bulbs, stems, and leaves. Plants want animals to eat their fruits (and interact with their flowers and seeds), but plants need to protect other body parts–their vegetable parts— from predators, so they can survive. I would argue that plants do not want their vegetable parts to be eaten.
Roots and tubers
Examples of roots: carrots and beets Examples of tubers: potatoes and yams
Roots and tubers are carbohydrate storage organs, so they are mostly made of starch. Starch is what plants use for energy (animals prefer to use fat). Starch is very heavy, so it’s easiest for the plant to store it on the ground or underground, in roots and tubers, instead of up top in branches or leaves.
Bulbs
Examples of bulbs: onions, garlic
Bulbs are immature plants that contain lots of starch to nourish the baby into adulthood.
Stems
Examples of stems: broccoli, asparagus, celery
The job of the stem is to hold the plant upright and deliver nutrients from its roots to its tips, so it has to be strong. This is why stems are very high in insoluble fiber, or cellulose. This is a very tough, stringy, woody type of plant carbohydrate that humans cannot digest.
Leaves
Examples of leaves: spinach, lettuce, kale
The leaf is the plant’s solar panel, catching the sun’s rays and turning them into energy through photosynthesis. Photosynthesis is the magical process that plants use to turn carbon dioxide and water into sugar and oxygen, using sunlight.
Do we need vegetables in our diet?
As outrageous as this may sound, I find no scientific evidence that vegetables are essential components of the human diet, because I am not aware of a single study that compares a diet containing vegetables to a diet without vegetables.
Thankfully, scientific laboratories are not our only sources of valuable information about the world. There’s real life evidence we can turn to that can answer our question.
We happen to know that a number of populations throughout history have eaten diets containing extremely few or even no vegetables, and historical reports tell us that these people were very healthy. Eskimo populations at the turn of the 20th century are the clearest examples of this phenomenon. No plants grow up there, so these frozen folks had no choice but to eat an essentially all-animal diet. Physician explorers of the time (before trade routes exposed traditional peoples to outside foods) observed that cancer was virtually nonexistent in Eskimo villages.
Even if the historical record doesn’t prompt you to wonder whether vegetables are really necessary in the fight against cancer, it should at least convince you that vegetables are not required in the human diet for daily bodily function. That these people were somehow able to get all of their essential vitamins and minerals entirely from animal foods I find to be fascinating and important information. These were not short-term studies lasting weeks or months or a couple of years. These were real people living entire lifetimes, being physically active, reproducing, etc., with little to no vegetable matter in their diet (and therefore virtually no carbohydrate). No biased researchers, no study subjects guessing about what they ate or cheating on their diets. I would argue that this kind of evidence is far more convincing than any scientific study.
Are vegetables good for us?
Okay, so they don’t seem to be necessary, but how do we know that Eskimos wouldn’t have been even healthier if they had added vegetables to their all-meat diet? We don’t know. So let’s look at the scientific research to see what it tells us about vegetables and health.
The reason why we are led to believe that vegetables are good for us is that there are thousands of epidemiological studies comparing high-vegetable diets to low-vegetable diets, and often (but not always), the people eating high-vegetable diets seem healthier. So why isn’t that convincing? Because when epidemiologists compare two different diets, there are usually LOTS of differences between those two diets, not just the amount of vegetable consumed.
For example, because people believe vegetables are healthy, people who eat more vegetables tend to be more health-conscious in general. Health-conscious people also tend to do lots of other things differently from the average person—they may eat less processed food, drink less alcohol, smoke less, eat less sugar, count calories, exercise more, etc. These other differences are very hard to account for in studies. The only way to really figure out if vegetables are healthy is to compare a diet with vegetables to a diet without vegetables. I know of no scientific study that has done this.
So, epidemiological studies suggest that people who eat more vegetables might be healthier. In order to prove this hypothesis, we need to do experiments. What do actual clinical experiments tell us?
I compiled the following information for a recent presentation I gave at the Ancestral Health Symposium [you can watch the video at the bottom of this post!]:
As of this writing (August 2012), there are 762 clinical studies listed in PubMed (a scientific search engine) having to do with vegetables and human health. Most of these are studies of how to get people to eat more vegetables; there are very few clinical trials attempting to show that vegetables are healthy. There were only 38 clinical studies designed to evaluate specific health effects of actual vegetables (as opposed to special concentrated vegetable extracts or isolated vegetable nutrients), and the vast majority of these (31 of the 38), unfortunately, used fruits and vegetables, instead of just vegetables. Fruits are so different from vegetables that it’s like comparing apples and oranges . . . except that it’s even worse, because at least apples and oranges are both fruits! However, let’s try to ignore these major design flaws and see what researchers found.
Eighteen of these 38 clinical studies were “negative”, meaning the researchers did not find the health benefit they were looking for. The remaining 20 studies were “positive”, meaning researchers found a health benefit when they compared groups of people who ate more (fruits and) vegetables to those who ate less of these foods.
Twenty positive studies is nothing to sneeze at, so at first glance, one might think that eating more (fruits and) vegetables might be a good idea. However, upon closer scrutiny, flaws become obvious that make it impossible, unfortunately, to know whether the results are actually due to the (fruits and) vegetables and not to some other factor.
Of the 20 positive studies, 10 did not take refined carbohydrate into consideration. This means that the group of people who ate more (fruits and) vegetables might have been healthier because they were eating less refined carbohydrate than the group that ate fewer vegetables.
The remaining 10 “positive” studies did not simply increase the amount of (fruits and) vegetables people ate; they also changed other aspects of lifestyle, such as fat consumption, alcohol intake, smoking, exercise, salt use, and/or refined carbohydrate intake. Therefore, we do not know whether the people who ate more (fruits and) vegetables were healthier because of the vegetables or because of some other aspect of the intervention.
Oh, and in case you’re wondering, of the 7 lonely studies that did look only at vegetables (instead of fruits and vegetables together), 6 of those 7 studies just happened to fall into the negative category, meaning that the vegetable(s) did not provide the health benefit expected. Hmmm.
So, we don’t have any clear scientific proof yet that vegetables are healthy for us. However, just because scientists have not yet conducted the kinds of studies that can tell us whether vegetables are healthy does not mean that they are not good for us; it just means that the idea that vegetables are good for us remains an unproven hypothesis.
Don’t we need to eat vegetables for fiber?
Fiber is an important enough topic that I gave it its own page on the site.
Aren’t vegetables important sources of vitamins and minerals?
In the following table you can see that animal products are superior sources of most essential vitamins and minerals, including four that do not exist in plant foods at all:
Aren’t vegetable antioxidants important for health?
This is a very complicated topic, and I’ll be writing lots more about this over time. For starters, many vegetable antioxidants that appear to have anti-cancer and anti-inflammatory properties in laboratory studies also happen to be the same chemical weapons that plants use to defend themselves. Therefore, it makes sense that many of these isolated compounds not only have the power to kill cancer cells, they also have the power to kill healthy, normal cells. Like any form of chemotherapy, the most powerful vegetable antioxidants are, at best, double-edged swords. [I go into more detail about antioxidants on my fruits page.]
Since antioxidants from each vegetable family are numerous, unique and complex, they will be explored in detail in the special occasional articles in my food blog. From cruciferous vegetables like broccoli to nightshades like white potato, you will discover the clever ways in which each vegetable family protects itself in the world, and how its specialized defensive chemicals affect your body.
The first veggie blog post, “Is Broccoli Good for You? Meet the Crucifer Family,” looks at how crucifers use sulforaphanes to protect themselves and how that might impact your health. “How Deadly Are Nightshades?” includes lots of interesting information about potatoes, as well as about tomatoes and eggplants (which are actually fruits masquerading as vegetables).
Bottom line about vegetables
There is no scientific evidence proving that vegetables are necessary, let alone good for us. However, most vegetables are naturally filling, low in carbohydrate, and low in calories, and therefore may be useful alternatives to junk food, sweets, baked goods, dairy products, and seed foods (grains, beans, nuts and seeds) when trying to control weight. Very sweet and starchy high glycemic index vegetables, such as white potatoes and beets, are exceptions to this rule.
Due to high fiber content, vegetables can be hard to digest, especially if eaten raw.
Vegetable nutrients are harder for us to absorb and use than animal food nutrients.
Vegetables contain naturally-occurring defensive chemicals that are designed to harm creatures that try to feast upon them. These chemicals are very toxic to living cells, however, the concentrations that exist in most types of whole vegetables may be relatively safe for most people to eat in moderation. Vegetable extracts and concentrates may not be as safe as whole vegetables because the “dose” of vegetable chemicals is much higher in these products. Some vegetable families contain more potent toxins than others and are the most likely to cause trouble for sensitive people.
Some vegetables are actually fruits, because they contain seeds. Examples of fruits masquerading as vegetables include: cucumbers, tomatoes, eggplant, and squashes. Pureed preparations of these “vegetables” which include pureed seeds are probably riskier choices, as seeds contain especially harmful chemicals that are released when seeds are pureed.
Some vegetables are actually legumes. Examples include green beans, wax beans, and snow peas. The pods or beans inside of these vegetables pose special risks to our health. For more information, see the grains, beans, nuts, seeds page.
Young vegetable sprouts contain higher concentrations of potentially harmful chemicals than mature vegetables because baby plants are vulnerable and need more protection from predators.
As a general rule, toxins are more likely to be concentrated in the skins of vegetables, to protect the plant on its outer surface. Sensitive individuals may therefore want to skin vegetables before eating. Cooking can also reduce the activity of some of these chemicals.
We and most of our ancestors have been eating vegetables for as long as 2 million years, so our bodies have adapted some ways of handling their natural toxins that may reduce their risk to our health. This is probably not true of “newer” foods, such as seed foods (5,000 to 10,000 years), refined carbohydrates (100-150 years), and artificial food additives (about 70 years). Therefore, vegetables are likely to be superior choices when compared to these newer foods.
Watch my 2012 Ancestral Health Symposium presentation about the the risks and benefits of eating vegetables:
We are told that vegetables are powerful and virtuous—that they fight off cancer, sweep our digestive systems clean, and strengthen our immune system—that they can leap tall buildings in a single bound. Yet vegetables have a dark side. They don’t want to be eaten any more than animals do, and use sophisticated chemical weapons to defend themselves . . .
Vegetable psychology
We think of them as virtuous, vital components of a healthy diet . . . yet vegetables are cunning and manipulative.
Deep down they don’t care about us. Our health is not their top priority; their top priority is their own survival. Plants have been on earth for hundreds of millions of years and they have learned a thing or two about survival.
Pretend you are a plant:
You can’t run away from animals that stop to dine on you. You can’t growl to scare predators away. You can’t wander around to meet other plants and reproduce. You can’t brush off caterpillars that are nibbling on you. You can’t swat away the insects that stop to bite you.
How do you protect yourself?
Well, you might have thorns or other special structures to help deter some invaders, but mostly you use chemical weapons . . . and very sophisticated ones, at that. Plants have been on this planet a lot longer than we have and they’ve got our number. They know what we like and don’t like. They know how our cells work. They know our strengths and weaknesses.
They have gone out of their way to make some vegetable parts taste bitter, so that we are less likely to want to eat them. In fact, the produce industry has had to work hard to breed bitterness out of vegetables so that we will be more likely to buy them. These bitter substances not only taste bad, they also function as highly specialized pesticides that are designed to kill insects, larvae, worms, bacteria, and fungi. These include things like:
Specialized immune system molecules that recognize invaders, attach to them, and mark them for the kill.
Poisons that kill cells and mitochondria by bursting their membranes open.
Enzyme inhibitors that interfere with vital metabolic reactions.
Oxidative toxins that break DNA strands
Because we believe that vegetables are good for us, we spend lots of time, energy, and money trying to prove how these bitter pesticides might be beneficial to human health. Because many of these same chemicals function as “antioxidants” in the laboratory, scientists enjoy studying how they might be used to fight cancer and other diseases.
Fair enough, but wouldn’t it make sense to also wonder whether these chemicals might be harmful to us?
What are vegetables?
Vegetables are any plant parts that are not fruits, seeds, or flowers. Vegetable parts include roots, tubers, bulbs, stems, and leaves. Plants want animals to eat their fruits (and interact with their flowers and seeds), but plants need to protect other body parts–their vegetable parts— from predators, so they can survive. I would argue that plants do not want their vegetable parts to be eaten.
Roots and tubers
Examples of roots: carrots and beets Examples of tubers: potatoes and yams
Roots and tubers are carbohydrate storage organs, so they are mostly made of starch. Starch is what plants use for energy (animals prefer to use fat). Starch is very heavy, so it’s easiest for the plant to store it on the ground or underground, in roots and tubers, instead of up top in branches or leaves.
Bulbs
Examples of bulbs: onions, garlic
Bulbs are immature plants that contain lots of starch to nourish the baby into adulthood.
Stems
Examples of stems: broccoli, asparagus, celery
The job of the stem is to hold the plant upright and deliver nutrients from its roots to its tips, so it has to be strong. This is why stems are very high in insoluble fiber, or cellulose. This is a very tough, stringy, woody type of plant carbohydrate that humans cannot digest.
Leaves
Examples of leaves: spinach, lettuce, kale
The leaf is the plant’s solar panel, catching the sun’s rays and turning them into energy through photosynthesis. Photosynthesis is the magical process that plants use to turn carbon dioxide and water into sugar and oxygen, using sunlight.
Do we need vegetables in our diet?
As outrageous as this may sound, I find no scientific evidence that vegetables are essential components of the human diet, because I am not aware of a single study that compares a diet containing vegetables to a diet without vegetables.
Thankfully, scientific laboratories are not our only sources of valuable information about the world. There’s real life evidence we can turn to that can answer our question.
We happen to know that a number of populations throughout history have eaten diets containing extremely few or even no vegetables, and historical reports tell us that these people were very healthy. Eskimo populations at the turn of the 20th century are the clearest examples of this phenomenon. No plants grow up there, so these frozen folks had no choice but to eat an essentially all-animal diet. Physician explorers of the time (before trade routes exposed traditional peoples to outside foods) observed that cancer was virtually nonexistent in Eskimo villages.
Even if the historical record doesn’t prompt you to wonder whether vegetables are really necessary in the fight against cancer, it should at least convince you that vegetables are not required in the human diet for daily bodily function. That these people were somehow able to get all of their essential vitamins and minerals entirely from animal foods I find to be fascinating and important information. These were not short-term studies lasting weeks or months or a couple of years. These were real people living entire lifetimes, being physically active, reproducing, etc., with little to no vegetable matter in their diet (and therefore virtually no carbohydrate). No biased researchers, no study subjects guessing about what they ate or cheating on their diets. I would argue that this kind of evidence is far more convincing than any scientific study.
Are vegetables good for us?
Okay, so they don’t seem to be necessary, but how do we know that Eskimos wouldn’t have been even healthier if they had added vegetables to their all-meat diet? We don’t know. So let’s look at the scientific research to see what it tells us about vegetables and health.
The reason why we are led to believe that vegetables are good for us is that there are thousands of epidemiological studies comparing high-vegetable diets to low-vegetable diets, and often (but not always), the people eating high-vegetable diets seem healthier. So why isn’t that convincing? Because when epidemiologists compare two different diets, there are usually LOTS of differences between those two diets, not just the amount of vegetable consumed.
For example, because people believe vegetables are healthy, people who eat more vegetables tend to be more health-conscious in general. Health-conscious people also tend to do lots of other things differently from the average person—they may eat less processed food, drink less alcohol, smoke less, eat less sugar, count calories, exercise more, etc. These other differences are very hard to account for in studies. The only way to really figure out if vegetables are healthy is to compare a diet with vegetables to a diet without vegetables. I know of no scientific study that has done this.
So, epidemiological studies suggest that people who eat more vegetables might be healthier. In order to prove this hypothesis, we need to do experiments. What do actual clinical experiments tell us?
I compiled the following information for a recent presentation I gave at the Ancestral Health Symposium [you can watch the video at the bottom of this post!]:
As of this writing (August 2012), there are 762 clinical studies listed in PubMed (a scientific search engine) having to do with vegetables and human health. Most of these are studies of how to get people to eat more vegetables; there are very few clinical trials attempting to show that vegetables are healthy. There were only 38 clinical studies designed to evaluate specific health effects of actual vegetables (as opposed to special concentrated vegetable extracts or isolated vegetable nutrients), and the vast majority of these (31 of the 38), unfortunately, used fruits and vegetables, instead of just vegetables. Fruits are so different from vegetables that it’s like comparing apples and oranges . . . except that it’s even worse, because at least apples and oranges are both fruits! However, let’s try to ignore these major design flaws and see what researchers found.
Eighteen of these 38 clinical studies were “negative”, meaning the researchers did not find the health benefit they were looking for. The remaining 20 studies were “positive”, meaning researchers found a health benefit when they compared groups of people who ate more (fruits and) vegetables to those who ate less of these foods.
Twenty positive studies is nothing to sneeze at, so at first glance, one might think that eating more (fruits and) vegetables might be a good idea. However, upon closer scrutiny, flaws become obvious that make it impossible, unfortunately, to know whether the results are actually due to the (fruits and) vegetables and not to some other factor.
Of the 20 positive studies, 10 did not take refined carbohydrate into consideration. This means that the group of people who ate more (fruits and) vegetables might have been healthier because they were eating less refined carbohydrate than the group that ate fewer vegetables.
The remaining 10 “positive” studies did not simply increase the amount of (fruits and) vegetables people ate; they also changed other aspects of lifestyle, such as fat consumption, alcohol intake, smoking, exercise, salt use, and/or refined carbohydrate intake. Therefore, we do not know whether the people who ate more (fruits and) vegetables were healthier because of the vegetables or because of some other aspect of the intervention.
Oh, and in case you’re wondering, of the 7 lonely studies that did look only at vegetables (instead of fruits and vegetables together), 6 of those 7 studies just happened to fall into the negative category, meaning that the vegetable(s) did not provide the health benefit expected. Hmmm.
So, we don’t have any clear scientific proof yet that vegetables are healthy for us. However, just because scientists have not yet conducted the kinds of studies that can tell us whether vegetables are healthy does not mean that they are not good for us; it just means that the idea that vegetables are good for us remains an unproven hypothesis.
Don’t we need to eat vegetables for fiber?
Fiber is an important enough topic that I gave it its own page on the site.
Aren’t vegetables important sources of vitamins and minerals?
In the following table you can see that animal products are superior sources of most essential vitamins and minerals, including four that do not exist in plant foods at all:
Aren’t vegetable antioxidants important for health?
This is a very complicated topic, and I’ll be writing lots more about this over time. For starters, many vegetable antioxidants that appear to have anti-cancer and anti-inflammatory properties in laboratory studies also happen to be the same chemical weapons that plants use to defend themselves. Therefore, it makes sense that many of these isolated compounds not only have the power to kill cancer cells, they also have the power to kill healthy, normal cells. Like any form of chemotherapy, the most powerful vegetable antioxidants are, at best, double-edged swords. [I go into more detail about antioxidants on my fruits page.]
Since antioxidants from each vegetable family are numerous, unique and complex, they will be explored in detail in the special occasional articles in my food blog. From cruciferous vegetables like broccoli to nightshades like white potato, you will discover the clever ways in which each vegetable family protects itself in the world, and how its specialized defensive chemicals affect your body.
The first veggie blog post, “Is Broccoli Good for You? Meet the Crucifer Family,” looks at how crucifers use sulforaphanes to protect themselves and how that might impact your health. “How Deadly Are Nightshades?” includes lots of interesting information about potatoes, as well as about tomatoes and eggplants (which are actually fruits masquerading as vegetables).
Bottom line about vegetables
There is no scientific evidence proving that vegetables are necessary, let alone good for us. However, most vegetables are naturally filling, low in carbohydrate, and low in calories, and therefore may be useful alternatives to junk food, sweets, baked goods, dairy products, and seed foods (grains, beans, nuts and seeds) when trying to control weight. Very sweet and starchy high glycemic index vegetables, such as white potatoes and beets, are exceptions to this rule.
Due to high fiber content, vegetables can be hard to digest, especially if eaten raw.
Vegetable nutrients are harder for us to absorb and use than animal food nutrients.
Vegetables contain naturally-occurring defensive chemicals that are designed to harm creatures that try to feast upon them. These chemicals are very toxic to living cells, however, the concentrations that exist in most types of whole vegetables may be relatively safe for most people to eat in moderation. Vegetable extracts and concentrates may not be as safe as whole vegetables because the “dose” of vegetable chemicals is much higher in these products. Some vegetable families contain more potent toxins than others and are the most likely to cause trouble for sensitive people.
Some vegetables are actually fruits, because they contain seeds. Examples of fruits masquerading as vegetables include: cucumbers, tomatoes, eggplant, and squashes. Pureed preparations of these “vegetables” which include pureed seeds are probably riskier choices, as seeds contain especially harmful chemicals that are released when seeds are pureed.
Some vegetables are actually legumes. Examples include green beans, wax beans, and snow peas. The pods or beans inside of these vegetables pose special risks to our health. For more information, see the grains, beans, nuts, seeds page.
Young vegetable sprouts contain higher concentrations of potentially harmful chemicals than mature vegetables because baby plants are vulnerable and need more protection from predators.
As a general rule, toxins are more likely to be concentrated in the skins of vegetables, to protect the plant on its outer surface. Sensitive individuals may therefore want to skin vegetables before eating. Cooking can also reduce the activity of some of these chemicals.
We and most of our ancestors have been eating vegetables for as long as 2 million years, so our bodies have adapted some ways of handling their natural toxins that may reduce their risk to our health. This is probably not true of “newer” foods, such as seed foods (5,000 to 10,000 years), refined carbohydrates (100-150 years), and artificial food additives (about 70 years). Therefore, vegetables are likely to be superior choices when compared to these newer foods.
Watch my 2012 Ancestral Health Symposium presentation about the the risks and benefits of eating vegetables:
Dairy products such as milk, yogurt, cheese and cream—any foods made from the milk of other mammals—are a versatile and beloved staple food of the American diet. Dairy products were not part of the human diet until about 10,000 years ago, when livestock were first domesticated. We are told that these foods are essential to a healthy diet, yet for nearly two million years humans and pre-humans thrived on little to no dairy foods at all. We are told that the high levels of calcium in milk are important for the formation of strong bones and healthy teeth. Dairy products are also an inexpensive source of high quality protein. How could a food that our ancestors lived without for so long be considered essential to our health today? Were we designed to require the milk of another species for our own growth and development? Or have we outsmarted Mother Nature and found a way to be healthier than our ancestors by adding dairy to our diets?
Many people have trouble processing dairy foods, and most don’t even realize it. Since most of us in the West have been consuming dairy products every single day since we were very young, we may not make the connection between troublesome symptoms and dairy foods. Some of the most common problems that can be caused by dairy include digestive disorders, asthma, upper respiratory tract infections, muscle and joint pains, urinary tract irritation, migraine, acne and eczema.
When we talk about milk, we are usually referring to cow’s milk. Cow’s milk is a complicated and highly specialized food designed to nourish and grow a baby cow. Therefore, it contains all kinds of interesting things—basic nutritional building blocks like proteins, fats, and carbohydrates, as well as minerals, vitamins, antibodies, growth factors, and other substances to stimulate the development of the little cow. The quality and amount of each of these components varies greatly, depending on the type of cow, how she is raised, and what she is fed. Let’s break milk down into its many parts to see what we are actually getting.
INGREDIENTS:
Milk sugar
Milk proteins
Milk fat
Minerals
Hormones
Milk sugar: lactose and lactose intolerance
What is lactose?
Lactose is the type of sugar found in all kinds of mammal milk—from human breast milk to cows’ milk to camels’ milk—the lactose is exactly the same. Each lactose molecule is made of two individual sugar molecules—one glucose molecule linked to one galactose molecule. We can absorb glucose and galactose easily, but we can’t absorb them when they are linked together as lactose. So, when we are babies, and dependent on mother’s milk, we have a special enzyme in our intestines called lactase, which breaks the link and frees up the glucose and galactose, so that we can absorb them. Lactase is like a little pair of chemical scissors that cuts the lactose in half.
What is lactose intolerance?
If you ask me, lactose intolerance is not a medical problem; it’s simply a sign that you’ve grown up.
Between the ages of two and five, most humans lose most or all of their ability to produce lactase, so most of us are lactose intolerant to some degree. Before agriculture was born (at most 10,000 years ago), humans did not have the ability to digest milk in early childhood, after weaning from breast milk. So, all of our hunter-gatherer ancestors were lactose intolerant. However, once people started eating dairy products regularly, a genetic shift occurred that allowed some people to keep the ability to digest milk into their adult years. These people are called “lactase persistent.” They essentially evolved the ability to tolerate lactose.
However, most of us still lose that ability, so by the time we are in grade school, we lack enough of the lactase enzyme to properly digest lactose. Without lactase, the lactose can’t be broken down and absorbed, so it continues on down the gastrointestinal tract, until it eventually encounters intestinal bacteria, who very much enjoy dining upon it. Unfortunately, they don’t break it into glucose and galactose for us. Instead, bacteria ferment the lactose, releasing lactic acid and gases in the process. Not only will these gases make you unpopular at parties, but they can cause you significant bloating, pain, and/or diarrhea, as well.
How common is lactose intolerance?
Approximately two-thirds to three-quarters of the world’s population is lactose intolerant, with the prevalence varying depending on ethnic background. Rates in Asia approach 100%. It is hard to know exactly how many Americans are lactose intolerant, but estimates suggest that approximately 15% of Caucasian Americans, 53% of Hispanic Americans, and 80% of African Americans may have lactose intolerance.
Studies show that lactose intolerance may be a matter of degree for some people. If you are 100% lactose intolerant, you don’t make any lactase at all, while “lactose tolerant” people make enough lactase to digest about 92% of all the lactose they eat. But there are some people in the middle, who make a small amount of lactase. These people can get away with eating small amounts of dairy foods, but if they eat too much, they won’t have enough lactase to digest it, so they will get symptoms of lactose intolerance. Everyone’s tolerance is different. Even most people who test positive for lactose intolerance can get away with drinking up to a cup of milk per day without any significant symptoms.
How do I know if I am lactose intolerant?
If dairy products bother you, you can ask your doctor for a lactose intolerance test. If you are lactose intolerant, the lactose you eat will make it all the way down to your colon, where the bacteria ferment it and create hydrogen gas. This gas passes into your bloodstream, then into your lungs, and comes out in your breath. In the lactose tolerance test, you will be given some lactose, and then your breath will be tested for hydrogen gas. If you breathe out hydrogen gas after eating lactose, you are lactose intolerant. If dairy products bother you and your test result is negative, then you don’t have lactose intolerance, but instead you may have trouble with other ingredients in dairy products, most likely milk protein (see below).
If I’m lactose intolerant, do I have to give up all dairy products?
As far as we know, lactose intolerance is not dangerous to your health. If you have lactose intolerance, there may still be ways for you to comfortably enjoy dairy products. There are many dairy products which contain little to no lactose. These include heavy cream (not half-and-half), sour cream, most hard cheeses (the bacteria used to age cheeses eat all the lactose), butter, and ghee (clarified butter).
Read the product label; since all of the carbohydrates in dairy products are lactose, the higher the carbohydrate gram count, the higher the lactose content. If the carbohydrate content is zero grams, then the product is virtually lactose-free. If you wish to eat foods that contain lactose, you may want to try an over-the-counter lactase product like Lact-Aid®, to help you digest lactose. Lactose-reduced milks are available, as well. Consuming dairy products with meals can also help to reduce the risk of uncomfortable symptoms.
Milk protein: casein and whey
Remember Little Miss Muffett—the chick who sat on her tuffett, eating her curds and whey?
Well, she must have let her milk sit out too long and curdle. If you let milk curdle, what you get are curds (like the lumps in cottage cheese) and whey (the watery stuff that floats to the top). These are the two main protein groups in milk—the curds are made of casein proteins and the whey contains whey proteins.
Caseins
The casein portion of milk is protein-rich and contains most of milk’s calcium. Caseins are very sticky and clump together (casein has historically been used as the active ingredient in wood glue). Caseins are actually designed by nature to form a clot in the stomach. Why in the world would a newborn want a lump of protein in its stomach? It’s ingenious, really—if the proteins don’t stick together, they get rapidly digested and absorbed. Digestive enzymes take longer to chew their way into the middle of a clump, so casein is essentially an extended-release source of protein that is gradually broken down over a number of hours, rather than all at once.
Caseins are very difficult to digest compared to wheys, and cow’s milk contains a LOT more casein than human breast milk. Cow’s milk contains 3 to 4 times as much protein per cup compared to human breast milk because—hello—it’s designed to grow a baby cow, which is SO much bigger than a baby human and grows a LOT faster. A newborn calf can weigh between 40 and 100 pounds, depending on the breed, and gains about 1-1/2 pounds per day, so it needs a LOT more protein. Also, the ratio of caseins to wheys is very different in cow’s milk vs. human milk:
Cow’s milk protein ratio: 80% caseins and 20% wheys
Human milk protein ratio: 40% caseins and 60% wheys*
* Milk composition varies depending on stage of breastfeeding; whey protein is very high in early stages (about 80% whey + 20% casein) and lower in later stages (about 50% whey + 50% casein).
So, cow’s milk contains approximately 6 times more casein per cup than human breast milk does. How does the baby cow handle all of that sticky casein?
Well, first of all, a baby cow has a completely different digestive system than a baby human does. Not only does a baby cow have FOUR stomachs, the baby cow also has a special enzyme in one of its stomachs called “rennet.” This enzyme is designed to digest the large amount of casein in their mother’s milk. Rennet breaks up the casein clumps into digestible particles. Human babies do not have rennet.
Are cow’s caseins and human caseins different?
There are lots of differences between cow’s caseins and human caseins, but the biggest difference is that the major type of casein found in human breast milk is beta casein, and the major type found in cow’s milk is alpha S1 casein. Alpha S1 casein from cow’s milk is the most common cause of milk protein allergies. All types of mammal milk, including cow’s milk and human milk, also contain another type of casein called kappa casein, but kappa casein comes in two very different forms—a “ruminant” form (for animals with more than one stomach, like cows) and a “non-ruminant” form (for animals with only one stomach, like humans).
It is likely that these major differences between the types of proteins in cow’s milk vs. human milk, and the absence of rennet in the human digestive tract are largely responsible for the significant gastrointestinal distress that can occur in people who are sensitive to cow’s milk products.
Whey proteins
Compared to caseins, whey proteins are softer, finer, much more easily digestible proteins. These proteins include lactoferrin, albumin, and lactalbumin. The whey portion also holds most of the milk’s lactose, as well as the IgA antibodies necessary to pass immune protection from mother to baby.
Human whey proteins are also different from cow’s whey proteins. The primary whey proteins in human milk are lactoferrin, albumin, and lactalbumin, whereas the dominant whey protein in cow’s milk is lactoglobulin.
Milk protein allergy and sensitivity
True allergy symptoms
Many people who have trouble with dairy products do not have lactose intolerance; instead they have trouble with milk proteins. People with serious, true milk allergies are reacting to the proteins in the milk, not the lactose. A true (IgE-mediated) allergy will cause hives, swelling, flushing, rash, oral allergy syndrome (itching/burning in mouth/throat), and/or wheezing within two hours, and may require emergency treatment with epinephrine (EpiPen®) to avoid life-threatening anaphylactic shock. This is why people with true allergies should strictly avoid all dairy products.
How common is true milk allergy?
Cow’s milk protein allergy is the most common allergy in children, affecting 2 to 5% of children under the age of three. Symptoms usually appear within two months or less of feeding cow’s milk to a baby for the first time. The most common symptom of milk allergy in infants and young children is constipation. Other clues include: eczema, asthma, rhinitis (swollen/itchy nose and eyes), reflux, vomiting, and rectal bleeding. Ten percent of colic cases are due to cow’s milk protein allergy. Interestingly, if the nursing mother is consuming dairy products herself, her baby can develop an allergy to cow’s milk proteins through breastfeeding, but the risk is much lower (about 0.5%). In these uncommon cases, the mother is advised to remove dairy products from her own diet if she wishes to continue nursing her baby.
Which milk proteins cause allergy?
Any of the various proteins in milk can cause an allergy. The potentially problematic proteins in milk include casein (4 different kinds), whey, lactalbumin and lactoglobulin. Allergy to caseins is more common than allergy to whey proteins. One type of casein—alpha-S1 casein— is the most common culprit in true milk protein allergy sufferers.
If I’m allergic to cow’s milk, can I have sheep’s or goat’s milk instead?
Unfortunately, virtually 100% of those with a true cow’s milk allergy will also be allergic to sheep’s and goat’s milk, as well. Luckily, special formulas are available for babies who are allergic to cow’s milk. Eighty percent of milk-allergic children outgrow their true milk allergy by the age of 5. However, many of these children continue to have gastrointestinal issues related to milk products many years later. [Note: those with milk protein allergy have about a 10% chance of also being allergic to soy protein, and about a 10% chance of being allergic to a protein in milk and undercooked beef called bovine serum albumin.]
How can I know whether I am truly allergic or just sensitive?
Luckily, there are several kinds of tests available for true milk allergy, but there are no reliable tests available for milk protein sensitivity, which may be even more common than true milk protein allergy. Dairy sensitivity is the cause of colic in some infants, and is a common cause of recurrent ear infections, sinus congestion, and reflux/swallowing problems in infants and young children. Like all food sensitivities, the only way to know if you or your child has milk protein sensitivity is to eliminate all dairy products from the diet for two to four weeks to see if symptoms improve.
If I have milk protein sensitivity, do I have to avoid all dairy products?
In contrast to true allergies, sensitivities are not life-threatening, so you get to decide whether you continue to eat dairy proteins, how much, and how often. However, sensitivities can cause significant discomfort and even temporary disability in some people. If you discover that you have milk protein sensitivity, you may be able to tolerate low-protein dairy products.
There are a few dairy products which are extremely low in proteins, such as heavy cream (not half-and-half), butter, and sour cream. Read the label; if the product contains zero grams of protein, it may not bother you. Keep in mind that zero grams doesn’t mean that it’s guaranteed to be completely protein-free; there are often tiny amounts of proteins in these items. For example, butter is listed as having zero grams of protein, but there is enough protein in it to bother some people. If butter bothers you, you may want to try ghee, which is clarified butter, and is virtually protein-free.
The saturated fat in milk fat is called butterfat, and is one of the most complicated mixtures of fats found in nature. The types and relative amounts of fats in milk depend heavily on what the cow is eating, but the predominant fatty acids in butterfat are usually: oleic acid, palmitic acid, and myristic acid.
Omega-3 fatty acids
The amount of omega-3 polyunsaturated fatty acids in milk varies greatly, and depends on what the cow is fed. There are three omega-3 fatty acids: ALA, EPA, and DHA (see my fats page). Cow’s milk contains varying amounts of ALA, depending on what they eat. Grass-fed cows give milk that is higher in ALA.
Cow’s milk does not contain the other two omega-3 fatty acids, EPA or DHA. Human breast milk does contain DHA, with the amount varying greatly depending on the mother’s own diet. Women eating traditional whole foods diets have much higher levels of DHA in their breast milk than women who eat a typical Western diet.
Trans fat
You may be aware that trans fats are considered generally very unhealthy, particularly for the heart. However, the health risks associated with trans fats were connected to the trans fats found in industrially-produced hydrogenated vegetable oils. What many people don’t know is that there is a natural source of trans fats in the world: ruminant animals (animals with more than one stomach). Bacteria in the cow’s digestive tract turn unsaturated fatty acids, such as linoleic acid and alpha-linolenic acid, into trans fatty acids. These can then be absorbed by the cow, and incorporated into the cow’s milk and meat.
There are two naturally-occurring trans fatty acids in cow’s milk: conjugated linoleic acid (CLA) and vaccenic acid (VA). About 2 to 5% of the fat in dairy products consists of these natural trans fats. One cup of standard whole milk contains about 0.2 grams of trans fat. Note: pastured/grass-fed milk contains about twice as much CLA as grain-fed milk does.
Are the natural trans fats in dairy products unhealthy?
Ironically, the reason why there has been so much interest in these fats, particularly CLA, is because there have been numerous studies suggesting that CLA may have health benefits, namely anti-cancer properties in laboratory animals. There have been no human studies that have clarified this relationship, so we currently do not know if CLA has anti-cancer properties in people.
Because industrial trans fats were determined to be associated strongly with heart disease risk, it makes sense to wonder whether dairy trans fats such as CLA may be bad for the heart. So far, the studies have been very mixed, and there is no conclusion yet one way or the other.
Luckily, the amount of CLA that people take in from dairy products is quite small, so it may not matter whether it is good or bad for us. There are too few studies of VA to understand how it affects us. Not only that, even though we humans can’t make trans fatty acids from scratch, we are capable of converting some of the VA we eat to CLA, so whatever effects VA might have on us might be partly due to CLA. It’s complicated.
Milk and bone health
Cow’s milk contains about one gram of calcium per liter, about four times as much as human breast milk. There is nothing special about the calcium in milk; it is just as easily absorbed as other forms of calcium from other sources. People eating a typical Western diet absorb only about 40% of the calcium they consume.
We are taught that milk is essential for the growth and health of children, especially for nurturing strong bones, because it is such a good source of calcium. Yet, despite the fact that Americans eat more dairy products than people in most other countries, we still have a much higher rate of osteoporosis than many other countries. Osteoporosis seems to follow a similar worldwide pattern to many other “diseases of Western civilization.”
We are not yet entirely sure what it is about the Western diet or lifestyle that is responsible for increased risk for osteoporosis in Western countries such as the U.S., but it is important to keep in mind that the presence or absence of dairy products is only one potential puzzle piece.
We are not generally asked to consider the other elements of our diet that affect bone strength. Some of these other considerations include:
Vitamin D, which is critical to our ability to use calcium to build bone (Unfortified milk is not a significant source of Vitamin D. Most milk in the US has been fortified with Vitamin D since 1933.)
Access to high quality protein sources for bone growth
Plant food anti-nutrients, such as phytic acid and oxalates, which interfere with calcium absorption
Refined carbohydrates (there they are again . . .), which raise cortisol levels, setting the stage for bone loss
Milk hormones
How does cow’s milk grow a cow, and why should you care?
Job number one of all mammal milks is to make baby mammals grow. To grow, you need proteins, fats, and carbohydrates to build body parts, and milk has all of those ingredients. However, just pouring ingredients into an animal doesn’t cause growth unless the hormonal conditions are just right. Think about it this way: you can pour all the food you want into a 45-year-old woman but she will NOT get any taller.
How does the body know what to do with all the nutrients you are pouring into it? Should the nutrients be stored for later use? Burned for energy? Or turned into new cells? What types of cells? Bone? Muscle? Liver? All of these decisions are made by hormones.
So, Mother Nature not only gave milk all the ingredients needed for growth, she also included the directions about how to grow, when to grow, and what parts should grow. These directions come in the form of hormones called growth factors. As we digest the caseins and whey proteins in cow’s milk, they are broken down into growth factors that send signals to our body.
Please note that I am not referring here to added bovine growth hormone (added BGH). I am referring to the naturally occurring hormones in cow’s milk that are supposed to be there for the sake of the baby cow. This is why no milk can ever be labeled “free of growth hormone”—all cow’s milk, even from the healthiest, most humanely-treated, organically-raised, grass-fed cow, contains growth hormones.
Does cow’s milk affect human hormones?
Whey proteins in milk cause our insulin levels to rise. In fact, milk (which has a low glycemic index and therefore doesn’t cause our blood sugar to spike) causes our insulin levels to rise in a similar fashion to refined carbohydrates. I know that most of us think of insulin simply as the hormone that keeps our blood sugar in check, but this is really not its primary purpose. Insulin is the mother of all growth hormones; it is intimately involved with all aspects of growth (see my carbohydrates page).
Whey proteins in milk also signal our body’s growth hormone (or GH; also known as somatotropin) levels to rise. GH is critical for growing taller.
Casein proteins in milk tell our body’s IGF-1 (Insulin-like Growth Factor-1) levels to rise by as much as 30%. Cow’s milk also contains some IGF-1, which is identical to human IGF-1, but we are not sure if cow IGF-1 is absorbed by people.
GH and IGF-1 work together to grow longer bones and larger organs. They tell cells to multiply. Humans produce this same combination of hormones during puberty, which is why teenagers go through a dramatic growth spurt.
Cow’s milk also contains the pre-hormone 5-alpha-pregnanedione, which can be converted into dihydrotestosterone.
Does cow’s milk make children grow more or mature faster?
All of these special signaling hormones in milk are designed to make a baby cow grow bigger, so it makes perfect sense that cow’s milk might also contribute to the growth of children. Let’s see what the research says.
A number of epidemiological studies find an association between how much milk pregnant women drink and how much their babies weigh at time of delivery, but again, it is hard to be certain that milk itself was the only reason for higher birth weights. IGF-1 in mother’s blood, whether it is her own IGF-1 or whether she absorbed it from cow’s milk, cannot cross the placenta. However, IGF-1 may have effects on the placenta itself, which can in turn affect how babies grow.
A number of epidemiological studies have found that children between 2 and 5 years old who drink more milk tend to be taller. Studies of older children and teenagers are not as well-designed overall, and the results are very mixed. We do know that it is probably not the calcium in the milk that is making children grow faster or taller, because intervention studies (better able to show cause and effect) do not find any connection between how much calcium children get and how much they grow.
Studies to date do not find any association between milk intake and age of menarche (first menses) in girls.
Some may view the growth-promoting properties of cow’s milk as a benefit, helping children to grow tall. I’m not aware of any direct experimental evidence that helps us understand whether milk indeed makes children grow taller, but if it were true, would that be a good thing? We know we are supposed to drink human breast milk early in life, and that human breast milk is designed especially for our growth needs. The problem is that we are only supposed to be receiving this special growth-promoting drink when we are babies and need to grow a LOT, very quickly. Should we be drinking cow growth formula every day of our lives? What might you logically expect to happen if your body is being forced into growth mode all the time, when it shouldn’t be? Is there such a thing as bad growth?
Dairy products and cancer risk
Well, sure—cancer is, hands down, the scariest form of growth, and IGF-1 in particular is famous not only for promoting the growth of normal cells; it is also infamous for promoting the growth of cancer cells.
Some epidemiological studies in adults show an association between dairy products and increased risk for prostate cancer, while other epidemiological studies suggest that milk may reduce the risk for colon and bladder cancer in adults. Remember that epidemiological studies cannot speak to cause and effect relationships between foods and diseases, and therefore cannot show that drinking more milk may be the reason for any of these confusing associations. Cancer is a very complicated disease, and dairy products are very complicated foods. It is nearly impossible to tease out any real connection between these two things in epidemiological studies.
Therefore, it is not surprising that two very recent reviews of all pertinent studies of dairy products and cancer risk both concluded that there is not enough evidence to say whether dairy products increase or decrease the risk of various types of cancer.
Dairy products and body weight
Since milk stimulates insulin spikes, it would make sense to wonder whether milk increases our risk of obesity and the many other health problems associated with hyperinsulinemia (high insulin levels). (See my carbohydrates page.)
You may have heard commercials claiming that people who eat dairy products tend to weigh less. Unfortunately, it seems not to be true:
“Of 49 randomized trials assessing the effect of dairy products or calcium supplementation on body weight, 41 showed no effect, two demonstrated weight gain, one showed a lower rate of gain, and five showed weight loss . . . Consequently, the majority of the current evidence from clinical trials does not support the hypothesis that calcium or dairy consumption aids in weight or fat loss.” [Lanou and Bernard 2008]
Miscellaneous bioactive peptides in milk
Proteins in cow’s milk and human milk break down during digestion into smaller pieces called “peptides,” some of which have special biological functions.
Peptides with opioid (narcotic) properties
Some milk peptides have natural opioid properties; opioids you may be familiar with include narcotic medications such as morphine and codeine.
So, do milk opioids act like narcotics in our bodies? The natural opioids present in milk are apparently very weak, and may only have effects on the lining of the digestive tract, since it is unclear if they can be absorbed into the bloodstream, let alone cross the blood-brain barrier and make it into the brain. As you may know, opioids act to slow down the activity of the gastrointestinal tract (which is why narcotics tend to cause constipation), so it is possible that some sensitive people may experience this as a side effect of milk products. Some people point to the fact that there are opioid peptides in milk to support the notion that dairy products are addictive and sedating; however, there are no human studies I’m aware of at this time (2012) to help us understand the role that these opioids play in our bodies.
Do dairy products cause acne?
Acne is a disease of Western civilization, in that it is not found in peoples who eat traditional whole foods diets. This pattern strongly suggests a dietary cause.
In the past five years, researchers have begun conducting studies that are shedding light on the diet-acne connection. Two main dietary suspects are emerging from these early studies: dairy products and refined carbohydrates.
The whey portion of milk contains a growth factor called betacellulin. This growth factor binds to something called the epidermal growth factor receptor (EGFR), which stimulates the pilosebaceous unit (the follicle) to overproduce sebum (mixture of natural skin oils and skin cells), which can lead to acne lesions.
The whey portion of milk stimulates insulin and IGF-1 production, and these in turn can stimulate acne formation. High glycemic index and refined carbohydrates also stimulate insulin secretion.
Interestingly, low-fat dairy products contain much more whey protein than full-fat dairy products, so low-fat dairy products are more powerful triggers of risky insulin spikes than full-fat dairy products. The less fat a dairy product contains, the more whey protein it tends to contain. Therefore, non-fat dairy products contain the highest percentage of whey proteins. Since non-fat dairy products and refined carbohydrates both trigger insulin spikes, the worst case scenario would then be a non-fat yogurt with added sugar, or a sweetened skim milk product (such as non-fat chocolate milk). Some people believe that chocolate cause acne breakouts. Plain milk chocolate has not been properly studied yet, but it would make sense that this food, which contains both milk proteins and sugar, might contribute to acne.
We still need more studies to clarify these connections. While there have been a number of human clinical studies, we need larger, randomized, properly-controlled clinical trials that look specifically at these suspects. For more information, please see my post “The Secret to Outsmarting Your Acne.”
Does milk cause iron-deficiency anemia?
In babies less than 12 months old, cow’s milk increases the risk of iron deficiency. There are several theories about why this is. One theory is that the proteins in cow’s milk interfere with the absorption of iron from the baby’s intestines. Another theory is that, in about 40% of babies, cow’s milk causes microscopic bleeding from the baby’s digestive tract, and since blood contains iron, the baby loses a little bit of iron every day. This is one of the reasons why parents in the U.S. are advised not to feed cow’s milk to babies under one year of age.
Does milk increase mucus production in the sinuses, throat, or lungs?
Many people believe this to be true (this is why choral directors and voice coaches often advise singers to avoid dairy products prior to performances), but there have been no studies yet that can confirm or deny this belief. If you suspect this is true for you, remove dairy products from your diet for two weeks to see it makes a difference.
Bottom line about dairy products
Milk is not necessary for human life or health, and is therefore optional, unless you don’t have reliable access to other complete sources of protein and essential nutrients such as meat, seafood, poultry or eggs.
Babies under one year of age should not drink milk (unless other nutritious options are not available) because it increases their risk for iron-deficiency anemia.
Many people suffer from dairy intolerance, particularly people of Asian, African and Latin American ancestry.
My opinion about dairy products
There is plenty of strong evidence that dairy products can cause health problems and no good evidence that dairy products are essential to health (unless other nutritious foods are not available).
As with most foods, if you enjoy them, and they don’t seem to bother you, then you may choose to include them in your diet. However, the only way to know if they bother you is to remove them from your diet for several weeks (I would recommend one month) and see how you feel without them. If you choose to eat them, just be aware of the potential risks involved.
Since the most troublesome ingredients in dairy products are 1) milk proteins and 2) lactose, I would recommend choosing full-fat dairy products, since these are lower in proteins and lactose than low-fat versions, are more satisfying (therefore you may eat less of them), and they taste better to many people.
Dairy products such as milk, yogurt, cheese and cream—any foods made from the milk of other mammals—are a versatile and beloved staple food of the American diet. Dairy products were not part of the human diet until about 10,000 years ago, when livestock were first domesticated. We are told that these foods are essential to a healthy diet, yet for nearly two million years humans and pre-humans thrived on little to no dairy foods at all. We are told that the high levels of calcium in milk are important for the formation of strong bones and healthy teeth. Dairy products are also an inexpensive source of high quality protein. How could a food that our ancestors lived without for so long be considered essential to our health today? Were we designed to require the milk of another species for our own growth and development? Or have we outsmarted Mother Nature and found a way to be healthier than our ancestors by adding dairy to our diets?
Many people have trouble processing dairy foods, and most don’t even realize it. Since most of us in the West have been consuming dairy products every single day since we were very young, we may not make the connection between troublesome symptoms and dairy foods. Some of the most common problems that can be caused by dairy include digestive disorders, asthma, upper respiratory tract infections, muscle and joint pains, urinary tract irritation, migraine, acne and eczema.
When we talk about milk, we are usually referring to cow’s milk. Cow’s milk is a complicated and highly specialized food designed to nourish and grow a baby cow. Therefore, it contains all kinds of interesting things—basic nutritional building blocks like proteins, fats, and carbohydrates, as well as minerals, vitamins, antibodies, growth factors, and other substances to stimulate the development of the little cow. The quality and amount of each of these components varies greatly, depending on the type of cow, how she is raised, and what she is fed. Let’s break milk down into its many parts to see what we are actually getting.
INGREDIENTS:
Milk sugar
Milk proteins
Milk fat
Minerals
Hormones
Milk sugar: lactose and lactose intolerance
What is lactose?
Lactose is the type of sugar found in all kinds of mammal milk—from human breast milk to cows’ milk to camels’ milk—the lactose is exactly the same. Each lactose molecule is made of two individual sugar molecules—one glucose molecule linked to one galactose molecule. We can absorb glucose and galactose easily, but we can’t absorb them when they are linked together as lactose. So, when we are babies, and dependent on mother’s milk, we have a special enzyme in our intestines called lactase, which breaks the link and frees up the glucose and galactose, so that we can absorb them. Lactase is like a little pair of chemical scissors that cuts the lactose in half.
What is lactose intolerance?
If you ask me, lactose intolerance is not a medical problem; it’s simply a sign that you’ve grown up.
Between the ages of two and five, most humans lose most or all of their ability to produce lactase, so most of us are lactose intolerant to some degree. Before agriculture was born (at most 10,000 years ago), humans did not have the ability to digest milk in early childhood, after weaning from breast milk. So, all of our hunter-gatherer ancestors were lactose intolerant. However, once people started eating dairy products regularly, a genetic shift occurred that allowed some people to keep the ability to digest milk into their adult years. These people are called “lactase persistent.” They essentially evolved the ability to tolerate lactose.
However, most of us still lose that ability, so by the time we are in grade school, we lack enough of the lactase enzyme to properly digest lactose. Without lactase, the lactose can’t be broken down and absorbed, so it continues on down the gastrointestinal tract, until it eventually encounters intestinal bacteria, who very much enjoy dining upon it. Unfortunately, they don’t break it into glucose and galactose for us. Instead, bacteria ferment the lactose, releasing lactic acid and gases in the process. Not only will these gases make you unpopular at parties, but they can cause you significant bloating, pain, and/or diarrhea, as well.
How common is lactose intolerance?
Approximately two-thirds to three-quarters of the world’s population is lactose intolerant, with the prevalence varying depending on ethnic background. Rates in Asia approach 100%. It is hard to know exactly how many Americans are lactose intolerant, but estimates suggest that approximately 15% of Caucasian Americans, 53% of Hispanic Americans, and 80% of African Americans may have lactose intolerance.
Studies show that lactose intolerance may be a matter of degree for some people. If you are 100% lactose intolerant, you don’t make any lactase at all, while “lactose tolerant” people make enough lactase to digest about 92% of all the lactose they eat. But there are some people in the middle, who make a small amount of lactase. These people can get away with eating small amounts of dairy foods, but if they eat too much, they won’t have enough lactase to digest it, so they will get symptoms of lactose intolerance. Everyone’s tolerance is different. Even most people who test positive for lactose intolerance can get away with drinking up to a cup of milk per day without any significant symptoms.
How do I know if I am lactose intolerant?
If dairy products bother you, you can ask your doctor for a lactose intolerance test. If you are lactose intolerant, the lactose you eat will make it all the way down to your colon, where the bacteria ferment it and create hydrogen gas. This gas passes into your bloodstream, then into your lungs, and comes out in your breath. In the lactose tolerance test, you will be given some lactose, and then your breath will be tested for hydrogen gas. If you breathe out hydrogen gas after eating lactose, you are lactose intolerant. If dairy products bother you and your test result is negative, then you don’t have lactose intolerance, but instead you may have trouble with other ingredients in dairy products, most likely milk protein (see below).
If I’m lactose intolerant, do I have to give up all dairy products?
As far as we know, lactose intolerance is not dangerous to your health. If you have lactose intolerance, there may still be ways for you to comfortably enjoy dairy products. There are many dairy products which contain little to no lactose. These include heavy cream (not half-and-half), sour cream, most hard cheeses (the bacteria used to age cheeses eat all the lactose), butter, and ghee (clarified butter).
Read the product label; since all of the carbohydrates in dairy products are lactose, the higher the carbohydrate gram count, the higher the lactose content. If the carbohydrate content is zero grams, then the product is virtually lactose-free. If you wish to eat foods that contain lactose, you may want to try an over-the-counter lactase product like Lact-Aid®, to help you digest lactose. Lactose-reduced milks are available, as well. Consuming dairy products with meals can also help to reduce the risk of uncomfortable symptoms.
Milk protein: casein and whey
Remember Little Miss Muffett—the chick who sat on her tuffett, eating her curds and whey?
Well, she must have let her milk sit out too long and curdle. If you let milk curdle, what you get are curds (like the lumps in cottage cheese) and whey (the watery stuff that floats to the top). These are the two main protein groups in milk—the curds are made of casein proteins and the whey contains whey proteins.
Caseins
The casein portion of milk is protein-rich and contains most of milk’s calcium. Caseins are very sticky and clump together (casein has historically been used as the active ingredient in wood glue). Caseins are actually designed by nature to form a clot in the stomach. Why in the world would a newborn want a lump of protein in its stomach? It’s ingenious, really—if the proteins don’t stick together, they get rapidly digested and absorbed. Digestive enzymes take longer to chew their way into the middle of a clump, so casein is essentially an extended-release source of protein that is gradually broken down over a number of hours, rather than all at once.
Caseins are very difficult to digest compared to wheys, and cow’s milk contains a LOT more casein than human breast milk. Cow’s milk contains 3 to 4 times as much protein per cup compared to human breast milk because—hello—it’s designed to grow a baby cow, which is SO much bigger than a baby human and grows a LOT faster. A newborn calf can weigh between 40 and 100 pounds, depending on the breed, and gains about 1-1/2 pounds per day, so it needs a LOT more protein. Also, the ratio of caseins to wheys is very different in cow’s milk vs. human milk:
Cow’s milk protein ratio: 80% caseins and 20% wheys
Human milk protein ratio: 40% caseins and 60% wheys*
* Milk composition varies depending on stage of breastfeeding; whey protein is very high in early stages (about 80% whey + 20% casein) and lower in later stages (about 50% whey + 50% casein).
So, cow’s milk contains approximately 6 times more casein per cup than human breast milk does. How does the baby cow handle all of that sticky casein?
Well, first of all, a baby cow has a completely different digestive system than a baby human does. Not only does a baby cow have FOUR stomachs, the baby cow also has a special enzyme in one of its stomachs called “rennet.” This enzyme is designed to digest the large amount of casein in their mother’s milk. Rennet breaks up the casein clumps into digestible particles. Human babies do not have rennet.
Are cow’s caseins and human caseins different?
There are lots of differences between cow’s caseins and human caseins, but the biggest difference is that the major type of casein found in human breast milk is beta casein, and the major type found in cow’s milk is alpha S1 casein. Alpha S1 casein from cow’s milk is the most common cause of milk protein allergies. All types of mammal milk, including cow’s milk and human milk, also contain another type of casein called kappa casein, but kappa casein comes in two very different forms—a “ruminant” form (for animals with more than one stomach, like cows) and a “non-ruminant” form (for animals with only one stomach, like humans).
It is likely that these major differences between the types of proteins in cow’s milk vs. human milk, and the absence of rennet in the human digestive tract are largely responsible for the significant gastrointestinal distress that can occur in people who are sensitive to cow’s milk products.
Whey proteins
Compared to caseins, whey proteins are softer, finer, much more easily digestible proteins. These proteins include lactoferrin, albumin, and lactalbumin. The whey portion also holds most of the milk’s lactose, as well as the IgA antibodies necessary to pass immune protection from mother to baby.
Human whey proteins are also different from cow’s whey proteins. The primary whey proteins in human milk are lactoferrin, albumin, and lactalbumin, whereas the dominant whey protein in cow’s milk is lactoglobulin.
Milk protein allergy and sensitivity
True allergy symptoms
Many people who have trouble with dairy products do not have lactose intolerance; instead they have trouble with milk proteins. People with serious, true milk allergies are reacting to the proteins in the milk, not the lactose. A true (IgE-mediated) allergy will cause hives, swelling, flushing, rash, oral allergy syndrome (itching/burning in mouth/throat), and/or wheezing within two hours, and may require emergency treatment with epinephrine (EpiPen®) to avoid life-threatening anaphylactic shock. This is why people with true allergies should strictly avoid all dairy products.
How common is true milk allergy?
Cow’s milk protein allergy is the most common allergy in children, affecting 2 to 5% of children under the age of three. Symptoms usually appear within two months or less of feeding cow’s milk to a baby for the first time. The most common symptom of milk allergy in infants and young children is constipation. Other clues include: eczema, asthma, rhinitis (swollen/itchy nose and eyes), reflux, vomiting, and rectal bleeding. Ten percent of colic cases are due to cow’s milk protein allergy. Interestingly, if the nursing mother is consuming dairy products herself, her baby can develop an allergy to cow’s milk proteins through breastfeeding, but the risk is much lower (about 0.5%). In these uncommon cases, the mother is advised to remove dairy products from her own diet if she wishes to continue nursing her baby.
Which milk proteins cause allergy?
Any of the various proteins in milk can cause an allergy. The potentially problematic proteins in milk include casein (4 different kinds), whey, lactalbumin and lactoglobulin. Allergy to caseins is more common than allergy to whey proteins. One type of casein—alpha-S1 casein— is the most common culprit in true milk protein allergy sufferers.
If I’m allergic to cow’s milk, can I have sheep’s or goat’s milk instead?
Unfortunately, virtually 100% of those with a true cow’s milk allergy will also be allergic to sheep’s and goat’s milk, as well. Luckily, special formulas are available for babies who are allergic to cow’s milk. Eighty percent of milk-allergic children outgrow their true milk allergy by the age of 5. However, many of these children continue to have gastrointestinal issues related to milk products many years later. [Note: those with milk protein allergy have about a 10% chance of also being allergic to soy protein, and about a 10% chance of being allergic to a protein in milk and undercooked beef called bovine serum albumin.]
How can I know whether I am truly allergic or just sensitive?
Luckily, there are several kinds of tests available for true milk allergy, but there are no reliable tests available for milk protein sensitivity, which may be even more common than true milk protein allergy. Dairy sensitivity is the cause of colic in some infants, and is a common cause of recurrent ear infections, sinus congestion, and reflux/swallowing problems in infants and young children. Like all food sensitivities, the only way to know if you or your child has milk protein sensitivity is to eliminate all dairy products from the diet for two to four weeks to see if symptoms improve.
If I have milk protein sensitivity, do I have to avoid all dairy products?
In contrast to true allergies, sensitivities are not life-threatening, so you get to decide whether you continue to eat dairy proteins, how much, and how often. However, sensitivities can cause significant discomfort and even temporary disability in some people. If you discover that you have milk protein sensitivity, you may be able to tolerate low-protein dairy products.
There are a few dairy products which are extremely low in proteins, such as heavy cream (not half-and-half), butter, and sour cream. Read the label; if the product contains zero grams of protein, it may not bother you. Keep in mind that zero grams doesn’t mean that it’s guaranteed to be completely protein-free; there are often tiny amounts of proteins in these items. For example, butter is listed as having zero grams of protein, but there is enough protein in it to bother some people. If butter bothers you, you may want to try ghee, which is clarified butter, and is virtually protein-free.
The saturated fat in milk fat is called butterfat, and is one of the most complicated mixtures of fats found in nature. The types and relative amounts of fats in milk depend heavily on what the cow is eating, but the predominant fatty acids in butterfat are usually: oleic acid, palmitic acid, and myristic acid.
Omega-3 fatty acids
The amount of omega-3 polyunsaturated fatty acids in milk varies greatly, and depends on what the cow is fed. There are three omega-3 fatty acids: ALA, EPA, and DHA (see my fats page). Cow’s milk contains varying amounts of ALA, depending on what they eat. Grass-fed cows give milk that is higher in ALA.
Cow’s milk does not contain the other two omega-3 fatty acids, EPA or DHA. Human breast milk does contain DHA, with the amount varying greatly depending on the mother’s own diet. Women eating traditional whole foods diets have much higher levels of DHA in their breast milk than women who eat a typical Western diet.
Trans fat
You may be aware that trans fats are considered generally very unhealthy, particularly for the heart. However, the health risks associated with trans fats were connected to the trans fats found in industrially-produced hydrogenated vegetable oils. What many people don’t know is that there is a natural source of trans fats in the world: ruminant animals (animals with more than one stomach). Bacteria in the cow’s digestive tract turn unsaturated fatty acids, such as linoleic acid and alpha-linolenic acid, into trans fatty acids. These can then be absorbed by the cow, and incorporated into the cow’s milk and meat.
There are two naturally-occurring trans fatty acids in cow’s milk: conjugated linoleic acid (CLA) and vaccenic acid (VA). About 2 to 5% of the fat in dairy products consists of these natural trans fats. One cup of standard whole milk contains about 0.2 grams of trans fat. Note: pastured/grass-fed milk contains about twice as much CLA as grain-fed milk does.
Are the natural trans fats in dairy products unhealthy?
Ironically, the reason why there has been so much interest in these fats, particularly CLA, is because there have been numerous studies suggesting that CLA may have health benefits, namely anti-cancer properties in laboratory animals. There have been no human studies that have clarified this relationship, so we currently do not know if CLA has anti-cancer properties in people.
Because industrial trans fats were determined to be associated strongly with heart disease risk, it makes sense to wonder whether dairy trans fats such as CLA may be bad for the heart. So far, the studies have been very mixed, and there is no conclusion yet one way or the other.
Luckily, the amount of CLA that people take in from dairy products is quite small, so it may not matter whether it is good or bad for us. There are too few studies of VA to understand how it affects us. Not only that, even though we humans can’t make trans fatty acids from scratch, we are capable of converting some of the VA we eat to CLA, so whatever effects VA might have on us might be partly due to CLA. It’s complicated.
Milk and bone health
Cow’s milk contains about one gram of calcium per liter, about four times as much as human breast milk. There is nothing special about the calcium in milk; it is just as easily absorbed as other forms of calcium from other sources. People eating a typical Western diet absorb only about 40% of the calcium they consume.
We are taught that milk is essential for the growth and health of children, especially for nurturing strong bones, because it is such a good source of calcium. Yet, despite the fact that Americans eat more dairy products than people in most other countries, we still have a much higher rate of osteoporosis than many other countries. Osteoporosis seems to follow a similar worldwide pattern to many other “diseases of Western civilization.”
We are not yet entirely sure what it is about the Western diet or lifestyle that is responsible for increased risk for osteoporosis in Western countries such as the U.S., but it is important to keep in mind that the presence or absence of dairy products is only one potential puzzle piece.
We are not generally asked to consider the other elements of our diet that affect bone strength. Some of these other considerations include:
Vitamin D, which is critical to our ability to use calcium to build bone (Unfortified milk is not a significant source of Vitamin D. Most milk in the US has been fortified with Vitamin D since 1933.)
Access to high quality protein sources for bone growth
Plant food anti-nutrients, such as phytic acid and oxalates, which interfere with calcium absorption
Refined carbohydrates (there they are again . . .), which raise cortisol levels, setting the stage for bone loss
Milk hormones
How does cow’s milk grow a cow, and why should you care?
Job number one of all mammal milks is to make baby mammals grow. To grow, you need proteins, fats, and carbohydrates to build body parts, and milk has all of those ingredients. However, just pouring ingredients into an animal doesn’t cause growth unless the hormonal conditions are just right. Think about it this way: you can pour all the food you want into a 45-year-old woman but she will NOT get any taller.
How does the body know what to do with all the nutrients you are pouring into it? Should the nutrients be stored for later use? Burned for energy? Or turned into new cells? What types of cells? Bone? Muscle? Liver? All of these decisions are made by hormones.
So, Mother Nature not only gave milk all the ingredients needed for growth, she also included the directions about how to grow, when to grow, and what parts should grow. These directions come in the form of hormones called growth factors. As we digest the caseins and whey proteins in cow’s milk, they are broken down into growth factors that send signals to our body.
Please note that I am not referring here to added bovine growth hormone (added BGH). I am referring to the naturally occurring hormones in cow’s milk that are supposed to be there for the sake of the baby cow. This is why no milk can ever be labeled “free of growth hormone”—all cow’s milk, even from the healthiest, most humanely-treated, organically-raised, grass-fed cow, contains growth hormones.
Does cow’s milk affect human hormones?
Whey proteins in milk cause our insulin levels to rise. In fact, milk (which has a low glycemic index and therefore doesn’t cause our blood sugar to spike) causes our insulin levels to rise in a similar fashion to refined carbohydrates. I know that most of us think of insulin simply as the hormone that keeps our blood sugar in check, but this is really not its primary purpose. Insulin is the mother of all growth hormones; it is intimately involved with all aspects of growth (see my carbohydrates page).
Whey proteins in milk also signal our body’s growth hormone (or GH; also known as somatotropin) levels to rise. GH is critical for growing taller.
Casein proteins in milk tell our body’s IGF-1 (Insulin-like Growth Factor-1) levels to rise by as much as 30%. Cow’s milk also contains some IGF-1, which is identical to human IGF-1, but we are not sure if cow IGF-1 is absorbed by people.
GH and IGF-1 work together to grow longer bones and larger organs. They tell cells to multiply. Humans produce this same combination of hormones during puberty, which is why teenagers go through a dramatic growth spurt.
Cow’s milk also contains the pre-hormone 5-alpha-pregnanedione, which can be converted into dihydrotestosterone.
Does cow’s milk make children grow more or mature faster?
All of these special signaling hormones in milk are designed to make a baby cow grow bigger, so it makes perfect sense that cow’s milk might also contribute to the growth of children. Let’s see what the research says.
A number of epidemiological studies find an association between how much milk pregnant women drink and how much their babies weigh at time of delivery, but again, it is hard to be certain that milk itself was the only reason for higher birth weights. IGF-1 in mother’s blood, whether it is her own IGF-1 or whether she absorbed it from cow’s milk, cannot cross the placenta. However, IGF-1 may have effects on the placenta itself, which can in turn affect how babies grow.
A number of epidemiological studies have found that children between 2 and 5 years old who drink more milk tend to be taller. Studies of older children and teenagers are not as well-designed overall, and the results are very mixed. We do know that it is probably not the calcium in the milk that is making children grow faster or taller, because intervention studies (better able to show cause and effect) do not find any connection between how much calcium children get and how much they grow.
Studies to date do not find any association between milk intake and age of menarche (first menses) in girls.
Some may view the growth-promoting properties of cow’s milk as a benefit, helping children to grow tall. I’m not aware of any direct experimental evidence that helps us understand whether milk indeed makes children grow taller, but if it were true, would that be a good thing? We know we are supposed to drink human breast milk early in life, and that human breast milk is designed especially for our growth needs. The problem is that we are only supposed to be receiving this special growth-promoting drink when we are babies and need to grow a LOT, very quickly. Should we be drinking cow growth formula every day of our lives? What might you logically expect to happen if your body is being forced into growth mode all the time, when it shouldn’t be? Is there such a thing as bad growth?
Dairy products and cancer risk
Well, sure—cancer is, hands down, the scariest form of growth, and IGF-1 in particular is famous not only for promoting the growth of normal cells; it is also infamous for promoting the growth of cancer cells.
Some epidemiological studies in adults show an association between dairy products and increased risk for prostate cancer, while other epidemiological studies suggest that milk may reduce the risk for colon and bladder cancer in adults. Remember that epidemiological studies cannot speak to cause and effect relationships between foods and diseases, and therefore cannot show that drinking more milk may be the reason for any of these confusing associations. Cancer is a very complicated disease, and dairy products are very complicated foods. It is nearly impossible to tease out any real connection between these two things in epidemiological studies.
Therefore, it is not surprising that two very recent reviews of all pertinent studies of dairy products and cancer risk both concluded that there is not enough evidence to say whether dairy products increase or decrease the risk of various types of cancer.
Dairy products and body weight
Since milk stimulates insulin spikes, it would make sense to wonder whether milk increases our risk of obesity and the many other health problems associated with hyperinsulinemia (high insulin levels). (See my carbohydrates page.)
You may have heard commercials claiming that people who eat dairy products tend to weigh less. Unfortunately, it seems not to be true:
“Of 49 randomized trials assessing the effect of dairy products or calcium supplementation on body weight, 41 showed no effect, two demonstrated weight gain, one showed a lower rate of gain, and five showed weight loss . . . Consequently, the majority of the current evidence from clinical trials does not support the hypothesis that calcium or dairy consumption aids in weight or fat loss.” [Lanou and Bernard 2008]
Miscellaneous bioactive peptides in milk
Proteins in cow’s milk and human milk break down during digestion into smaller pieces called “peptides,” some of which have special biological functions.
Peptides with opioid (narcotic) properties
Some milk peptides have natural opioid properties; opioids you may be familiar with include narcotic medications such as morphine and codeine.
So, do milk opioids act like narcotics in our bodies? The natural opioids present in milk are apparently very weak, and may only have effects on the lining of the digestive tract, since it is unclear if they can be absorbed into the bloodstream, let alone cross the blood-brain barrier and make it into the brain. As you may know, opioids act to slow down the activity of the gastrointestinal tract (which is why narcotics tend to cause constipation), so it is possible that some sensitive people may experience this as a side effect of milk products. Some people point to the fact that there are opioid peptides in milk to support the notion that dairy products are addictive and sedating; however, there are no human studies I’m aware of at this time (2012) to help us understand the role that these opioids play in our bodies.
Do dairy products cause acne?
Acne is a disease of Western civilization, in that it is not found in peoples who eat traditional whole foods diets. This pattern strongly suggests a dietary cause.
In the past five years, researchers have begun conducting studies that are shedding light on the diet-acne connection. Two main dietary suspects are emerging from these early studies: dairy products and refined carbohydrates.
The whey portion of milk contains a growth factor called betacellulin. This growth factor binds to something called the epidermal growth factor receptor (EGFR), which stimulates the pilosebaceous unit (the follicle) to overproduce sebum (mixture of natural skin oils and skin cells), which can lead to acne lesions.
The whey portion of milk stimulates insulin and IGF-1 production, and these in turn can stimulate acne formation. High glycemic index and refined carbohydrates also stimulate insulin secretion.
Interestingly, low-fat dairy products contain much more whey protein than full-fat dairy products, so low-fat dairy products are more powerful triggers of risky insulin spikes than full-fat dairy products. The less fat a dairy product contains, the more whey protein it tends to contain. Therefore, non-fat dairy products contain the highest percentage of whey proteins. Since non-fat dairy products and refined carbohydrates both trigger insulin spikes, the worst case scenario would then be a non-fat yogurt with added sugar, or a sweetened skim milk product (such as non-fat chocolate milk). Some people believe that chocolate cause acne breakouts. Plain milk chocolate has not been properly studied yet, but it would make sense that this food, which contains both milk proteins and sugar, might contribute to acne.
We still need more studies to clarify these connections. While there have been a number of human clinical studies, we need larger, randomized, properly-controlled clinical trials that look specifically at these suspects. For more information, please see my post “The Secret to Outsmarting Your Acne.”
Does milk cause iron-deficiency anemia?
In babies less than 12 months old, cow’s milk increases the risk of iron deficiency. There are several theories about why this is. One theory is that the proteins in cow’s milk interfere with the absorption of iron from the baby’s intestines. Another theory is that, in about 40% of babies, cow’s milk causes microscopic bleeding from the baby’s digestive tract, and since blood contains iron, the baby loses a little bit of iron every day. This is one of the reasons why parents in the U.S. are advised not to feed cow’s milk to babies under one year of age.
Does milk increase mucus production in the sinuses, throat, or lungs?
Many people believe this to be true (this is why choral directors and voice coaches often advise singers to avoid dairy products prior to performances), but there have been no studies yet that can confirm or deny this belief. If you suspect this is true for you, remove dairy products from your diet for two weeks to see it makes a difference.
Bottom line about dairy products
Milk is not necessary for human life or health, and is therefore optional, unless you don’t have reliable access to other complete sources of protein and essential nutrients such as meat, seafood, poultry or eggs.
Babies under one year of age should not drink milk (unless other nutritious options are not available) because it increases their risk for iron-deficiency anemia.
Many people suffer from dairy intolerance, particularly people of Asian, African and Latin American ancestry.
My opinion about dairy products
There is plenty of strong evidence that dairy products can cause health problems and no good evidence that dairy products are essential to health (unless other nutritious foods are not available).
As with most foods, if you enjoy them, and they don’t seem to bother you, then you may choose to include them in your diet. However, the only way to know if they bother you is to remove them from your diet for several weeks (I would recommend one month) and see how you feel without them. If you choose to eat them, just be aware of the potential risks involved.
Since the most troublesome ingredients in dairy products are 1) milk proteins and 2) lactose, I would recommend choosing full-fat dairy products, since these are lower in proteins and lactose than low-fat versions, are more satisfying (therefore you may eat less of them), and they taste better to many people.
Grains, beans, nuts and seeds are all seeds. Rich in complex carbohydrates and fiber, they form the base of most healthy food pyramids. Yet grind grain into flour and suddenly you have a dangerous powder called “refined flour” that is supposed to be avoided like the plague. Gluten intolerance, soy, corn, and peanut allergies are on the rise. What’s going on here?
Yes, these foods are all in the same family—they are all seeds.
Grains are the seeds of grasses. Examples include: wheat, corn, oats, and rice
Beans are the seeds of legumes. Examples include: peas, lentils, soybeans, and chickpeas.
Nuts are the seeds of trees. Examples include walnuts, hazelnuts, and pecans.
And seeds are . . . well . . . seeds. Examples include sesame seeds, poppy seeds, and sunflower seeds.
Cut any of these things in half and you‘ll find the same basic structure inside.
This is why there is so much confusion about peanuts, cashews, and almonds, which some people struggle to categorize. Is a peanut a nut or a legume? Is quinoa a grain or a seed? Don’t worry—it doesn’t matter—they are all seeds. End of story.
What are seeds?
A seed is precious to the plant, since it houses the plant’s embryo—the baby plant—and plants have developed very powerful methods to protect it. Seeds are designed to survive for a very long time in harsh environments, because they have to sit around and wait for what may be a very long time for conditions to be just right to take root and sprout. They need to be able to resist cold, heat, insects, worms, bacteria, fungi, and seed-eating animals. In order to protect themselves from all of these dangers, seeds contain a variety of very smart chemicals, many of which have the potential to disrupt the health of unsuspecting humans.
All plants need help dispersing their seeds, because plants can’t move. Therefore, plants have evolved very clever ways of dispersing their seeds so that they will go forth and multiply. Some plants grow tasty fruits around their seeds to entice animals to eat them and carry them away.
But what about grass seeds that have no fruit? Wheat? Oats? Rice? Corn? Grasses rely primarily on wind to disperse their seeds. Grains do not come wrapped in sweet fruits, since they’re not designed to be eaten. Grains and legumes were not designed with the health of humans and animals in mind, so no special precautions were taken by the plant to minimize damage to our health. In fact, grains are toxic to humans in their raw state.
Are grains (and other seeds) essential in our diet?
For the 2 million years before agriculture was invented, our hunter-gatherer ancestors likely ate few, if any grains, so they are clearly not essential. There have been numerous cultures throughout history (the Inuit Eskimo is a good example) who, even well into the 20th century, ate a completely grain-free diet and were healthy.
Are grains (and other seeds) good for us?
The first time that grains and beans made up any significant portion of the human diet was between 5,000 and 10,000 years ago, when agriculture took hold. Before agriculture, humans were hunter-gatherers who ate animals and a variety of fruits and vegetables, depending on where they lived and the time of year. From an evolutionary standpoint, that’s not very long, so most of us have not had enough time to adapt to these difficult foods. Historical and anthropological records tell us that human health around the world declined in various ways after agriculture was born: most people were shorter, and their bodies showed evidence of mineral deficiencies, malnutrition, and infectious diseases. Since dairy products were also added to the human diet at around the same time as grains and legumes, it is hard to be sure whether health declined due to seed foods, dairy products, or both. However, as you’ll see below, all of the health problems that developed after agriculture could easily have been caused by seed food ingredients, whereas it would be theoretically difficult to tie them to dairy food ingredients (see my dairy page).
Why are we told that grains are healthy?
We are told that we are supposed to eat at least three servings of grain per day, and that half of the grains we eat should be whole grains, yet there is no evidence that grains improve health. So, where does this advice come from?
There are hundreds of studies proclaiming the health benefits of eating whole grains, but the problem is that these studies compare diets rich in whole grains to diets rich in refined grains and sugars. These studies do show that whole grains are healthier for us than refined grains (flours), but they do not prove that whole grains are healthy. In order to prove that, you’d have to compare a diet that contains grains to a diet that contains no grains. Pretty much any whole food is healthier for us than refined carbohydrates, so proving that whole grains beat refined carbohydrates is . . . well . . . a piece of cake. When you think about it, it doesn’t make sense to say that whole grains are healthy but that powdered grains are dangerous . . . how can the same food be both incredibly good and incredibly evil?
What makes more sense is to think of it like this: the more refined a grain is, the worse it is for you. The reason for this is probably that pulverizing the grains into flour releases more of the carbohydrates and other potentially damaging contents lurking inside the kernel. If we eat grains whole, the tough outer bran coating, or hull, of the grain keeps more of these pesky particles inside the grain. If we remove the hull by “polishing” the grain (white rice is a good example), there is nothing left to protect our bodies from being exposed to the starches and proteins inside.
Are nuts and seeds healthier than grains and beans?
I don’t know.
Paleo style diets allow nuts and seeds but not grains and beans, because many of our ancestors would likely have been eating nuts and seeds long before the invention of agriculture. Most nuts and some seeds do not require any processing to be edible, whereas all grains and legumes must be soaked, fermented, and/or thoroughly cooked in order not to cause immediate illness. Our ancestors have probably been eating nuts and seeds for a lot longer than they have been eating grains and legumes, so even though nuts and seeds contain similarly risky ingredients, it is possible that our genes have learned how to better handle nut and seed compounds because we have been exposed to them for hundreds of thousands of years. The best theoretical explanation I can think of for why nuts in particular may be healthier than grains, beans, or seeds is that nuts and seeds are protected by their hard shells and therefore may not need to incorporate as many defensive chemicals in their flesh as naked beans and grains. But I have not been able to find evidence of this possibility in the scientific literature.
Are grains, beans, nuts and seeds nutritious?
Grains are so low in nutritional value that most cereal products in the United States are fortified with vitamins and minerals. In fact, the US Dietary Guidelines recommends 50% of the grains you eat be refinedbecause they are fortified; eating the recommended daily number of servings of grains as whole grains alone would be nutritionally inadequate.
Of the four categories of seed foods, beans are usually thought of as being the most nutritious, due to their high protein content. As you can see from the nutrition information for cooked pinto beans, they are mostly made of starch (carbohydrate—something the body has no need for), along with some protein, fiber, and some iron.
Yes, there is some protein and some iron in these foods as well. However, all of these nutrients, because they come from seed foods, come with some baggage, as you’ll see below.
Seed proteins
Seed proteins are typically of lower quality due to missing essential amino acids (quinoa and soy are notable exceptions). For example, wheat protein is particularly low in lysine. Corn is especially low in tryptophan. Legumes (including soybeans) are especially low in sulfur-containing amino acids, cysteine and methionine.
Some of the proteins in seeds are naturally difficult for us to digest because of their special structure.
Some seed proteins are defensive molecules that are designed to irritate non-plant cells.
Lectins
The outer coatings of seeds are armed with proteins called lectins (aka phytohemagglutinins or agglutinins), which are part of the plant’s immune system. Lectins can recognize friend from foe by reading carbohydrates on the surfaces of the cells of would-be invaders. When a seed is stressed or damaged, lectins are released to identify and attack potential enemies. One of the many ways they can fend off an attack is to zero in on targets (such as bacteria), bind to their signature carbohydrates, and then cause them to clump together (agglutination) so they cannot advance. Insects, not people, are the natural predators of grains, so lectins can also cause infertility in insects.
Lectins are found in all plants and animals, not just in beans and grains. However, animal lectins and plant lectins are different; animal lectins are not known to harm the cells of other animals, whereas plant lectins can be risky for humans and other animals. The highest concentrations of the most potent plant lectins are found in the seeds, roots, young shoots, and bark of plants. In seeds, lectins are primarily found in the bran-rich outer coating, which is one reason why even whole grains are not necessarily healthy. Lectins can also be found in the oils of seeds and nuts. The most important food sources of lectins are grains, beans, nuts, seeds, tomatoes, white potatoes, limes, cinnamon, and Jerusalem artichokes.
What can lectins do to humans?
Because they bind to specific carbohydrates on the surfaces of living cells, lectins are very reactive. You can think of them as being sticky.
Lectins can bind to glycoproteins on the surface of our intestinal cells. Lectins have been shown in laboratory studies (in vitro) to damage human intestinal cells and in animal studies to poke holes in their intestinal linings, causing increased intestinal permeability (leaky gut). Leaky gut syndromes in humans have been associated with autoimmune diseases such as: rheumatoid arthritis, Celiac disease, type I diabetes, and multiple sclerosis.
We know that lectins cross into our bloodstream because healthy people have antibodies to lectins in their blood. In the bloodstream, lectins can bind to red blood cells, causing them to clump together (or agglutinate). Clumped blood cells are then destroyed by the body, so high doses of lectins can cause anemia.
Lectins can also bind to our immune cells and cause them to clump together, weakening our immune system. However, lectins can also bind to immune cells (mast cells and T cells) and activate them; this is a potential path to allergies and autoimmune diseases. They can also trigger white blood cells to release pro-inflammatory cytokines.
Lectins can enter cells, and once inside, they can bind to and inactivate ribosomes, which are the tiny protein factories inside of our cells.
In laboratory science, lectins are well-known as “mitogens”—which means that they can cause cells to multiply in a cancerous fashion. In laboratory studies, lectins can bind to immune cells called lymphocytes (T cells in particular) and trigger cancerous changes. In clinical human studies, ingestion of peanuts has been shown to have the ability to cause cancerous proliferation of colon cells.
How to reduce the lectin content of foods
Most lectins can be completely inactivated by pre-soaking foods and then bringing them to a full boil for 15 minutes. Dry heat (baking or roasting) is not as effective as prolonged boiling, so baked goods made with grain or bean flours are not as safe as boiled products. Dry roasting only removes about 75% of the lectins from raw peanuts. Toasted wheat germ contains active lectins, as well. Lectins laugh at stomach acid, and many lectins resist digestion by our intestinal enzymes. Lectins are the reason why grains and beans should never be eaten raw (kidney bean lectin is very toxic if eaten raw or undercooked, and will cause severe vomiting).
Sprouting reduces (but does not eliminate) lectins because once the seed starts to germinate and form a baby plant, much of the lectin protein gets broken down to nourish the growing seedling. However, some lectins remain to protect the growing plant.
Thus, there are really only two ways to protect yourself from the many potential hazards of lectins: prolonged boiling or avoidance.
There are many different types of lectins, with different carbohydrate targets, attack strategies, and potencies. The best-studied of the food lectins are: wheat germ agglutinin, peanut lectin, kidney bean lectin, soybean lectin, potato lectin and tomato lectin. In the future I will be writing more about these foods and their specific lectins.
Gluten
What is gluten?
Gluten is not a single protein; there are hundreds of proteins in the gluten family. Glutens are proteins found only in the following grains:
[Oat crops are often rotated or milled with wheat products, so oats are sometimes cross-contaminated with wheat glutens.]
Glutens are simply seed storage proteins—they are designed to nourish the plant embryo when it comes time to sprout. Sounds innocent enough . . . yet, glutens are not only the well-established cause of Celiac disease, a serious autoimmune condition affecting more than 1 in 100 people, but are also the cause of gluten sensitivity, which affects (probably many more than) 7 in 100 people.
Glutens and other storage proteins are found on the inside of all seed foods (in the endosperm), not in the bran-rich outer coating, which is probably why refined (powdered) grains are potentially less healthy than whole grains. All seeds contain storage proteins, but only the wheat family contains glutens. So, what’s so special about gluten?
Glutens contain stretches of repetitive amino acid sequences (rich in proline and glutamine) that are particularly difficult for our enzymes to digest. [Remember, the mother plant does not want this protein to be digested by anyone other than the baby plant.] Proteins that contain proline-rich sequences are called “prolamins”, and they are thought to be particularly irritating to our immune systems. All grains contain prolamins, but the types found in wheat (gliadin), rye (secalin), and barley (horedin), seem to be particularly irritating to the immune systems of susceptible individuals. [A small number of people are also sensitive to avenin, the prolamin found in oats.]
The problem with gluten being poorly digestible is not just that we have a hard time extracting nutritious proteins from gluten-rich foods. The problem is that partially digested glutens, which are called “toxic gliadin peptides”, can wreak havoc with the digestive and immune systems of genetically susceptible individuals, leading to gluten sensitivity and Celiac disease.
Wheat allergy
People who are have a true allergy to wheat are reacting to a specific wheat protein called omega-5 gliadin. This protein is only found in wheat—not in barley, rye, or triticale.
Seed antinutrients
An antinutrient is anything that interferes with the ability of the body to digest, absorb, or utilize a nutrient. Antinutrients in seed foods include enzyme inhibitors and phytic acid.
Enzyme inhibitors
Seed foods contain compounds that work against our digestive enzymes, making it harder for us to break foods down. These include protease inhibitors, which block protein digestion, and amylase inhibitors, which block starch digestion. Amylase inhibitors do not survive digestion, so they are not a concern. Protease inhibitors are mostly destroyed by cooking, so, in well-cooked seed foods, these would also not be a problem.
Phytic acid
Phytic acid, however, cannot be destroyed by cooking. The name phytic acid essentially means “plant acid” and was so named because it is not found in animal foods. It is located primarily in the bran-rich outer coating of seeds, which is one reason why even whole grains are not necessarily healthy.
Phytic acid is a mineral magnet. It binds to certain minerals in the foods we eat, and removes them from our bodies. This can lead to mineral deficiencies, such as iron-deficiency anemia. [The form of iron found in plant foods is difficult to absorb to begin with, because it is in the “non-heme” form, instead of the “heme” form found in animal foods.]
Below are results from two human studies of phytic acid. The first [Brune 1989] is an experiment showing that bran blocks the absorption of about 90% of the iron in wheat rolls, both in omnivores and in long-time vegetarians. This demonstrates that, even in people who have been eating high-plant diets for years, the body does not adapt to the antinutrient effects of phytic acid.
The second graph [Solomons 1979] shows the degree of interference that phytic acid can have on zinc absorption. Oysters are rich sources of zinc. When oysters are eaten alone, you can see the zinc level rise nicely in the bloodstream, indicating excellent absorption. When the oysters are eaten with black beans, people absorbed only about half the zinc from the oysters, and when oysters were eaten with corn tortillas, people absorbed virtually none of the zinc from the oysters. This is not a subtle effect. This study is important because it illustrates that phytic acid doesn’t just prevent the absorption of nutrients from the seeds themselves, but also from other nutrient-rich foods consumed with those seed foods.
*Note that taking vitamin C or eating vitamin C-rich foods along with high-phytate foods can improve mineral absorption.
Phytic acid is best at binding to “positively charged, multivalent cations”, which means that it prefers minerals with more than one positive charge, such as iron (Fe+2), calcium (Ca+2), zinc (Zn+2), magnesium (Mg+2) and copper (Cu+2), which are all essential minerals that we must obtain from our diet. [It is not good at binding minerals like sodium (Na+1) or potassium (K+1), which have only one positive charge.]
Phytic acid can also bind to food proteins and to our digestive enzymes, interfering with protein absorption.
Which foods are highest in phytic acid?
Phytic acid is found in all parts of plants, and therefore is found in all plant foods; however, the vast majority of it is located in seeds, where its job is to hold on tightly to the essential minerals (phosphorus, iron, zinc, etc.) that the baby plant will need to grow. Once the seed begins to sprout, phytic acid gets broken down so that those vital minerals can be released to the baby plant. This is why non-seed parts of the plant contain extremely low concentrations of phytic acid.
The amount of phytic acid in any given seed food varies tremendously, depending on a variety of factors—environmental conditions, age, plant variety, etc, so it’s hard to say, but some research indicates that seeds contain highest levels, followed by grains, and then legumes. The phytic acid content of nuts runs the gamut from low to high.
How to reduce phytic acid content
Most phytic acid is not digested; it survives our stomach acid and our intestinal enzymes, making it all the way down into the colon, where bacteria can start to break it down. Phytic acid does not appear to be absorbed by our systems, so it can only interfere with minerals in our digestive tract, not in our bloodstream or inside of our cells. Most phytic acid leaves our system intact, carrying minerals away with it.
Phytic acid is not affected by prolonged storage. Phytic acid cannot be destroyed by cooking, not even with prolonged boiling. Extrusion cooking, which is used by manufacturers in the industrial production of breakfast cereals, for example, barely reduces phytic acid content.
Phytic acid might be partially reduced by soaking and/or sprouting. For example, when performed properly, under just the right conditions, between 1/3 to 2/3 of phytic acid can be removed from beans.
Fermentation, particularly sourdough fermentation, is the most effective method for removing phytic acid from foods, because microorganisms, unlike humans, have the ability to digest phytic acid.
Seed starches
Plants store energy as starch, which is just a bunch of simple sugar molecules linked together. Seeds are very high in starch because the baby plant will need a source of energy when it starts growing.
Much of the starch inside seeds is either amylose or amylopectin, which are both made of long chains of glucose molecules, and therefore easily broken down into glucose and absorbed as glucose into the bloodstream. However, there are two types of seed carbohydrates that our digestive enzymes can’t break down:
Fructo-oligosaccharides (chains of fructose molecules)
Galacto-oligosaccharides (chains of galactose + glucose + fructose). Examples include raffinose and stachyose.
Beans, beans, the wonderful fruit…
Most seed foods contain some combination of the indigestible carbohydrates listed above, but beans are best known for causing digestive problems. This is because legumes are especially high in the galacto-oligosaccharides stachyose and raffinose.
Bacteria living in the colon make an enzyme called “alpha-galactosidase” which can break apart the sugar molecules in these carbohydrates. Then the bacteria proceed to ferment those sugars, creating unwelcome gases: carbon dioxide, hydrogen, and/or methane. Beano® contains the same enzyme that bacteria use. By swallowing Beano® before eating beans, raffinose and stachyose will get broken down into sugars long before reaching the colon, so the small intestine can absorb the sugars before the bacteria can get to them.
Of note, rice is extremely low in indigestible carbohydrates, and therefore very little gas is produced during its digestion. Spelt is also quite low in these substances.
Cyanogenic glycosides
These innocent chemicals are mainly found lurking deep inside the rugged pits of fruits, such as apricots, peaches, cherries, mangoes, and plums. These types of seeds are virtually indestructible without tools, and it’s a good thing we can’t chew them open. When these seeds are damaged, the nontoxic glycosides mix with an activating enzyme and poof—you’ve got cyanide. Other foods that can generate cyanide include: bitter almonds, marzipan, bamboo shoots, cassava root (tapioca), lima beans, sorghum, apple seeds and pear seeds. Proper processing of these foods by grinding, boiling and soaking can remove the cyanide and make them safer to eat.
The human body can detoxify tiny quantities of cyanide, but at higher doses, cyanide can interfere with iodine within your thyroid gland and cause goiter or hypothyroidism. At higher doses still, cyanide can suffocate your mitochondria (your cells’ energy generators), which can be fatal.
Bottom line about seed foods
Of all natural plant and animal foods available to humans, seed foods are the foods most likely to endanger human health. Therefore, eliminating foods from this family is the single most important dietary change you can make to improve and protect your health.
For people who either choose not to eat animal foods, or do not have access to animal foods, this food group does contain the highest amounts of protein of all of the plant foods, and can be a far less expensive source of protein than meat and dairy products.
However:
these proteins can be difficult to digest, partly due to their nature and partly due to anti-nutrients within these foods
certain proteins, such as gluten, can be particularly irritating to the digestive tract and immune system of susceptible individuals
lectins within seed foods are potentially hazardous, making boiling or steaming to remove these risky substances before consumption very important.
Some of the starches in seed foods cannot be digested by our intestinal enzymes, therefore they ferment in the colon, creating gases.
The mineral-thief phytic acid is very difficult to completely remove from these foods, even with fermentation techniques, therefore these foods significantly increase the risk for mineral deficiencies, especially iron deficiency and associated anemia. Taking vitamin C can improve the absorption of iron.
If you choose to eat seed foods such as grains, it is best to eat them whole, rather than ground into refined flours.
Rice may be safer and more comfortable to eat than other grains because it
does not contain gluten
is extremely low in indigestible starches
is typically boiled (or steamed) before eaten, which destroys all lectins
It is unclear to me whether nuts and seeds are healthier than grains and legumes.
Grains, beans, nuts and seeds are all seeds. Rich in complex carbohydrates and fiber, they form the base of most healthy food pyramids. Yet grind grain into flour and suddenly you have a dangerous powder called “refined flour” that is supposed to be avoided like the plague. Gluten intolerance, soy, corn, and peanut allergies are on the rise. What’s going on here?
Yes, these foods are all in the same family—they are all seeds.
Grains are the seeds of grasses. Examples include: wheat, corn, oats, and rice
Beans are the seeds of legumes. Examples include: peas, lentils, soybeans, and chickpeas.
Nuts are the seeds of trees. Examples include walnuts, hazelnuts, and pecans.
And seeds are . . . well . . . seeds. Examples include sesame seeds, poppy seeds, and sunflower seeds.
Cut any of these things in half and you‘ll find the same basic structure inside.
This is why there is so much confusion about peanuts, cashews, and almonds, which some people struggle to categorize. Is a peanut a nut or a legume? Is quinoa a grain or a seed? Don’t worry—it doesn’t matter—they are all seeds. End of story.
What are seeds?
A seed is precious to the plant, since it houses the plant’s embryo—the baby plant—and plants have developed very powerful methods to protect it. Seeds are designed to survive for a very long time in harsh environments, because they have to sit around and wait for what may be a very long time for conditions to be just right to take root and sprout. They need to be able to resist cold, heat, insects, worms, bacteria, fungi, and seed-eating animals. In order to protect themselves from all of these dangers, seeds contain a variety of very smart chemicals, many of which have the potential to disrupt the health of unsuspecting humans.
All plants need help dispersing their seeds, because plants can’t move. Therefore, plants have evolved very clever ways of dispersing their seeds so that they will go forth and multiply. Some plants grow tasty fruits around their seeds to entice animals to eat them and carry them away.
But what about grass seeds that have no fruit? Wheat? Oats? Rice? Corn? Grasses rely primarily on wind to disperse their seeds. Grains do not come wrapped in sweet fruits, since they’re not designed to be eaten. Grains and legumes were not designed with the health of humans and animals in mind, so no special precautions were taken by the plant to minimize damage to our health. In fact, grains are toxic to humans in their raw state.
Are grains (and other seeds) essential in our diet?
For the 2 million years before agriculture was invented, our hunter-gatherer ancestors likely ate few, if any grains, so they are clearly not essential. There have been numerous cultures throughout history (the Inuit Eskimo is a good example) who, even well into the 20th century, ate a completely grain-free diet and were healthy.
Are grains (and other seeds) good for us?
The first time that grains and beans made up any significant portion of the human diet was between 5,000 and 10,000 years ago, when agriculture took hold. Before agriculture, humans were hunter-gatherers who ate animals and a variety of fruits and vegetables, depending on where they lived and the time of year. From an evolutionary standpoint, that’s not very long, so most of us have not had enough time to adapt to these difficult foods. Historical and anthropological records tell us that human health around the world declined in various ways after agriculture was born: most people were shorter, and their bodies showed evidence of mineral deficiencies, malnutrition, and infectious diseases. Since dairy products were also added to the human diet at around the same time as grains and legumes, it is hard to be sure whether health declined due to seed foods, dairy products, or both. However, as you’ll see below, all of the health problems that developed after agriculture could easily have been caused by seed food ingredients, whereas it would be theoretically difficult to tie them to dairy food ingredients (see my dairy page).
Why are we told that grains are healthy?
We are told that we are supposed to eat at least three servings of grain per day, and that half of the grains we eat should be whole grains, yet there is no evidence that grains improve health. So, where does this advice come from?
There are hundreds of studies proclaiming the health benefits of eating whole grains, but the problem is that these studies compare diets rich in whole grains to diets rich in refined grains and sugars. These studies do show that whole grains are healthier for us than refined grains (flours), but they do not prove that whole grains are healthy. In order to prove that, you’d have to compare a diet that contains grains to a diet that contains no grains. Pretty much any whole food is healthier for us than refined carbohydrates, so proving that whole grains beat refined carbohydrates is . . . well . . . a piece of cake. When you think about it, it doesn’t make sense to say that whole grains are healthy but that powdered grains are dangerous . . . how can the same food be both incredibly good and incredibly evil?
What makes more sense is to think of it like this: the more refined a grain is, the worse it is for you. The reason for this is probably that pulverizing the grains into flour releases more of the carbohydrates and other potentially damaging contents lurking inside the kernel. If we eat grains whole, the tough outer bran coating, or hull, of the grain keeps more of these pesky particles inside the grain. If we remove the hull by “polishing” the grain (white rice is a good example), there is nothing left to protect our bodies from being exposed to the starches and proteins inside.
Are nuts and seeds healthier than grains and beans?
I don’t know.
Paleo style diets allow nuts and seeds but not grains and beans, because many of our ancestors would likely have been eating nuts and seeds long before the invention of agriculture. Most nuts and some seeds do not require any processing to be edible, whereas all grains and legumes must be soaked, fermented, and/or thoroughly cooked in order not to cause immediate illness. Our ancestors have probably been eating nuts and seeds for a lot longer than they have been eating grains and legumes, so even though nuts and seeds contain similarly risky ingredients, it is possible that our genes have learned how to better handle nut and seed compounds because we have been exposed to them for hundreds of thousands of years. The best theoretical explanation I can think of for why nuts in particular may be healthier than grains, beans, or seeds is that nuts and seeds are protected by their hard shells and therefore may not need to incorporate as many defensive chemicals in their flesh as naked beans and grains. But I have not been able to find evidence of this possibility in the scientific literature.
Are grains, beans, nuts and seeds nutritious?
Grains are so low in nutritional value that most cereal products in the United States are fortified with vitamins and minerals. In fact, the US Dietary Guidelines recommends 50% of the grains you eat be refinedbecause they are fortified; eating the recommended daily number of servings of grains as whole grains alone would be nutritionally inadequate.
Of the four categories of seed foods, beans are usually thought of as being the most nutritious, due to their high protein content. As you can see from the nutrition information for cooked pinto beans, they are mostly made of starch (carbohydrate—something the body has no need for), along with some protein, fiber, and some iron.
Yes, there is some protein and some iron in these foods as well. However, all of these nutrients, because they come from seed foods, come with some baggage, as you’ll see below.
Seed proteins
Seed proteins are typically of lower quality due to missing essential amino acids (quinoa and soy are notable exceptions). For example, wheat protein is particularly low in lysine. Corn is especially low in tryptophan. Legumes (including soybeans) are especially low in sulfur-containing amino acids, cysteine and methionine.
Some of the proteins in seeds are naturally difficult for us to digest because of their special structure.
Some seed proteins are defensive molecules that are designed to irritate non-plant cells.
Lectins
The outer coatings of seeds are armed with proteins called lectins (aka phytohemagglutinins or agglutinins), which are part of the plant’s immune system. Lectins can recognize friend from foe by reading carbohydrates on the surfaces of the cells of would-be invaders. When a seed is stressed or damaged, lectins are released to identify and attack potential enemies. One of the many ways they can fend off an attack is to zero in on targets (such as bacteria), bind to their signature carbohydrates, and then cause them to clump together (agglutination) so they cannot advance. Insects, not people, are the natural predators of grains, so lectins can also cause infertility in insects.
Lectins are found in all plants and animals, not just in beans and grains. However, animal lectins and plant lectins are different; animal lectins are not known to harm the cells of other animals, whereas plant lectins can be risky for humans and other animals. The highest concentrations of the most potent plant lectins are found in the seeds, roots, young shoots, and bark of plants. In seeds, lectins are primarily found in the bran-rich outer coating, which is one reason why even whole grains are not necessarily healthy. Lectins can also be found in the oils of seeds and nuts. The most important food sources of lectins are grains, beans, nuts, seeds, tomatoes, white potatoes, limes, cinnamon, and Jerusalem artichokes.
What can lectins do to humans?
Because they bind to specific carbohydrates on the surfaces of living cells, lectins are very reactive. You can think of them as being sticky.
Lectins can bind to glycoproteins on the surface of our intestinal cells. Lectins have been shown in laboratory studies (in vitro) to damage human intestinal cells and in animal studies to poke holes in their intestinal linings, causing increased intestinal permeability (leaky gut). Leaky gut syndromes in humans have been associated with autoimmune diseases such as: rheumatoid arthritis, Celiac disease, type I diabetes, and multiple sclerosis.
We know that lectins cross into our bloodstream because healthy people have antibodies to lectins in their blood. In the bloodstream, lectins can bind to red blood cells, causing them to clump together (or agglutinate). Clumped blood cells are then destroyed by the body, so high doses of lectins can cause anemia.
Lectins can also bind to our immune cells and cause them to clump together, weakening our immune system. However, lectins can also bind to immune cells (mast cells and T cells) and activate them; this is a potential path to allergies and autoimmune diseases. They can also trigger white blood cells to release pro-inflammatory cytokines.
Lectins can enter cells, and once inside, they can bind to and inactivate ribosomes, which are the tiny protein factories inside of our cells.
In laboratory science, lectins are well-known as “mitogens”—which means that they can cause cells to multiply in a cancerous fashion. In laboratory studies, lectins can bind to immune cells called lymphocytes (T cells in particular) and trigger cancerous changes. In clinical human studies, ingestion of peanuts has been shown to have the ability to cause cancerous proliferation of colon cells.
How to reduce the lectin content of foods
Most lectins can be completely inactivated by pre-soaking foods and then bringing them to a full boil for 15 minutes. Dry heat (baking or roasting) is not as effective as prolonged boiling, so baked goods made with grain or bean flours are not as safe as boiled products. Dry roasting only removes about 75% of the lectins from raw peanuts. Toasted wheat germ contains active lectins, as well. Lectins laugh at stomach acid, and many lectins resist digestion by our intestinal enzymes. Lectins are the reason why grains and beans should never be eaten raw (kidney bean lectin is very toxic if eaten raw or undercooked, and will cause severe vomiting).
Sprouting reduces (but does not eliminate) lectins because once the seed starts to germinate and form a baby plant, much of the lectin protein gets broken down to nourish the growing seedling. However, some lectins remain to protect the growing plant.
Thus, there are really only two ways to protect yourself from the many potential hazards of lectins: prolonged boiling or avoidance.
There are many different types of lectins, with different carbohydrate targets, attack strategies, and potencies. The best-studied of the food lectins are: wheat germ agglutinin, peanut lectin, kidney bean lectin, soybean lectin, potato lectin and tomato lectin. In the future I will be writing more about these foods and their specific lectins.
Gluten
What is gluten?
Gluten is not a single protein; there are hundreds of proteins in the gluten family. Glutens are proteins found only in the following grains:
[Oat crops are often rotated or milled with wheat products, so oats are sometimes cross-contaminated with wheat glutens.]
Glutens are simply seed storage proteins—they are designed to nourish the plant embryo when it comes time to sprout. Sounds innocent enough . . . yet, glutens are not only the well-established cause of Celiac disease, a serious autoimmune condition affecting more than 1 in 100 people, but are also the cause of gluten sensitivity, which affects (probably many more than) 7 in 100 people.
Glutens and other storage proteins are found on the inside of all seed foods (in the endosperm), not in the bran-rich outer coating, which is probably why refined (powdered) grains are potentially less healthy than whole grains. All seeds contain storage proteins, but only the wheat family contains glutens. So, what’s so special about gluten?
Glutens contain stretches of repetitive amino acid sequences (rich in proline and glutamine) that are particularly difficult for our enzymes to digest. [Remember, the mother plant does not want this protein to be digested by anyone other than the baby plant.] Proteins that contain proline-rich sequences are called “prolamins”, and they are thought to be particularly irritating to our immune systems. All grains contain prolamins, but the types found in wheat (gliadin), rye (secalin), and barley (horedin), seem to be particularly irritating to the immune systems of susceptible individuals. [A small number of people are also sensitive to avenin, the prolamin found in oats.]
The problem with gluten being poorly digestible is not just that we have a hard time extracting nutritious proteins from gluten-rich foods. The problem is that partially digested glutens, which are called “toxic gliadin peptides”, can wreak havoc with the digestive and immune systems of genetically susceptible individuals, leading to gluten sensitivity and Celiac disease.
Wheat allergy
People who are have a true allergy to wheat are reacting to a specific wheat protein called omega-5 gliadin. This protein is only found in wheat—not in barley, rye, or triticale.
Seed antinutrients
An antinutrient is anything that interferes with the ability of the body to digest, absorb, or utilize a nutrient. Antinutrients in seed foods include enzyme inhibitors and phytic acid.
Enzyme inhibitors
Seed foods contain compounds that work against our digestive enzymes, making it harder for us to break foods down. These include protease inhibitors, which block protein digestion, and amylase inhibitors, which block starch digestion. Amylase inhibitors do not survive digestion, so they are not a concern. Protease inhibitors are mostly destroyed by cooking, so, in well-cooked seed foods, these would also not be a problem.
Phytic acid
Phytic acid, however, cannot be destroyed by cooking. The name phytic acid essentially means “plant acid” and was so named because it is not found in animal foods. It is located primarily in the bran-rich outer coating of seeds, which is one reason why even whole grains are not necessarily healthy.
Phytic acid is a mineral magnet. It binds to certain minerals in the foods we eat, and removes them from our bodies. This can lead to mineral deficiencies, such as iron-deficiency anemia. [The form of iron found in plant foods is difficult to absorb to begin with, because it is in the “non-heme” form, instead of the “heme” form found in animal foods.]
Below are results from two human studies of phytic acid. The first [Brune 1989] is an experiment showing that bran blocks the absorption of about 90% of the iron in wheat rolls, both in omnivores and in long-time vegetarians. This demonstrates that, even in people who have been eating high-plant diets for years, the body does not adapt to the antinutrient effects of phytic acid.
The second graph [Solomons 1979] shows the degree of interference that phytic acid can have on zinc absorption. Oysters are rich sources of zinc. When oysters are eaten alone, you can see the zinc level rise nicely in the bloodstream, indicating excellent absorption. When the oysters are eaten with black beans, people absorbed only about half the zinc from the oysters, and when oysters were eaten with corn tortillas, people absorbed virtually none of the zinc from the oysters. This is not a subtle effect. This study is important because it illustrates that phytic acid doesn’t just prevent the absorption of nutrients from the seeds themselves, but also from other nutrient-rich foods consumed with those seed foods.
*Note that taking vitamin C or eating vitamin C-rich foods along with high-phytate foods can improve mineral absorption.
Phytic acid is best at binding to “positively charged, multivalent cations”, which means that it prefers minerals with more than one positive charge, such as iron (Fe+2), calcium (Ca+2), zinc (Zn+2), magnesium (Mg+2) and copper (Cu+2), which are all essential minerals that we must obtain from our diet. [It is not good at binding minerals like sodium (Na+1) or potassium (K+1), which have only one positive charge.]
Phytic acid can also bind to food proteins and to our digestive enzymes, interfering with protein absorption.
Which foods are highest in phytic acid?
Phytic acid is found in all parts of plants, and therefore is found in all plant foods; however, the vast majority of it is located in seeds, where its job is to hold on tightly to the essential minerals (phosphorus, iron, zinc, etc.) that the baby plant will need to grow. Once the seed begins to sprout, phytic acid gets broken down so that those vital minerals can be released to the baby plant. This is why non-seed parts of the plant contain extremely low concentrations of phytic acid.
The amount of phytic acid in any given seed food varies tremendously, depending on a variety of factors—environmental conditions, age, plant variety, etc, so it’s hard to say, but some research indicates that seeds contain highest levels, followed by grains, and then legumes. The phytic acid content of nuts runs the gamut from low to high.
How to reduce phytic acid content
Most phytic acid is not digested; it survives our stomach acid and our intestinal enzymes, making it all the way down into the colon, where bacteria can start to break it down. Phytic acid does not appear to be absorbed by our systems, so it can only interfere with minerals in our digestive tract, not in our bloodstream or inside of our cells. Most phytic acid leaves our system intact, carrying minerals away with it.
Phytic acid is not affected by prolonged storage. Phytic acid cannot be destroyed by cooking, not even with prolonged boiling. Extrusion cooking, which is used by manufacturers in the industrial production of breakfast cereals, for example, barely reduces phytic acid content.
Phytic acid might be partially reduced by soaking and/or sprouting. For example, when performed properly, under just the right conditions, between 1/3 to 2/3 of phytic acid can be removed from beans.
Fermentation, particularly sourdough fermentation, is the most effective method for removing phytic acid from foods, because microorganisms, unlike humans, have the ability to digest phytic acid.
Seed starches
Plants store energy as starch, which is just a bunch of simple sugar molecules linked together. Seeds are very high in starch because the baby plant will need a source of energy when it starts growing.
Much of the starch inside seeds is either amylose or amylopectin, which are both made of long chains of glucose molecules, and therefore easily broken down into glucose and absorbed as glucose into the bloodstream. However, there are two types of seed carbohydrates that our digestive enzymes can’t break down:
Fructo-oligosaccharides (chains of fructose molecules)
Galacto-oligosaccharides (chains of galactose + glucose + fructose). Examples include raffinose and stachyose.
Beans, beans, the wonderful fruit…
Most seed foods contain some combination of the indigestible carbohydrates listed above, but beans are best known for causing digestive problems. This is because legumes are especially high in the galacto-oligosaccharides stachyose and raffinose.
Bacteria living in the colon make an enzyme called “alpha-galactosidase” which can break apart the sugar molecules in these carbohydrates. Then the bacteria proceed to ferment those sugars, creating unwelcome gases: carbon dioxide, hydrogen, and/or methane. Beano® contains the same enzyme that bacteria use. By swallowing Beano® before eating beans, raffinose and stachyose will get broken down into sugars long before reaching the colon, so the small intestine can absorb the sugars before the bacteria can get to them.
Of note, rice is extremely low in indigestible carbohydrates, and therefore very little gas is produced during its digestion. Spelt is also quite low in these substances.
Cyanogenic glycosides
These innocent chemicals are mainly found lurking deep inside the rugged pits of fruits, such as apricots, peaches, cherries, mangoes, and plums. These types of seeds are virtually indestructible without tools, and it’s a good thing we can’t chew them open. When these seeds are damaged, the nontoxic glycosides mix with an activating enzyme and poof—you’ve got cyanide. Other foods that can generate cyanide include: bitter almonds, marzipan, bamboo shoots, cassava root (tapioca), lima beans, sorghum, apple seeds and pear seeds. Proper processing of these foods by grinding, boiling and soaking can remove the cyanide and make them safer to eat.
The human body can detoxify tiny quantities of cyanide, but at higher doses, cyanide can interfere with iodine within your thyroid gland and cause goiter or hypothyroidism. At higher doses still, cyanide can suffocate your mitochondria (your cells’ energy generators), which can be fatal.
Bottom line about seed foods
Of all natural plant and animal foods available to humans, seed foods are the foods most likely to endanger human health. Therefore, eliminating foods from this family is the single most important dietary change you can make to improve and protect your health.
For people who either choose not to eat animal foods, or do not have access to animal foods, this food group does contain the highest amounts of protein of all of the plant foods, and can be a far less expensive source of protein than meat and dairy products.
However:
these proteins can be difficult to digest, partly due to their nature and partly due to anti-nutrients within these foods
certain proteins, such as gluten, can be particularly irritating to the digestive tract and immune system of susceptible individuals
lectins within seed foods are potentially hazardous, making boiling or steaming to remove these risky substances before consumption very important.
Some of the starches in seed foods cannot be digested by our intestinal enzymes, therefore they ferment in the colon, creating gases.
The mineral-thief phytic acid is very difficult to completely remove from these foods, even with fermentation techniques, therefore these foods significantly increase the risk for mineral deficiencies, especially iron deficiency and associated anemia. Taking vitamin C can improve the absorption of iron.
If you choose to eat seed foods such as grains, it is best to eat them whole, rather than ground into refined flours.
Rice may be safer and more comfortable to eat than other grains because it
does not contain gluten
is extremely low in indigestible starches
is typically boiled (or steamed) before eaten, which destroys all lectins
It is unclear to me whether nuts and seeds are healthier than grains and legumes.
All animals must eat protein regularly to survive, because we cannot make protein out of fat or carbohydrate or cholesterol. Proteins form enzymes, muscles, hormones, and other vital bodily components. How much protein do we need, and does it matter where we get it from?
What is protein?
Proteins are complicated molecules of many different shapes and sizes that are essential to all forms of life. Proteins are intimately involved in virtually everything that happens inside our cells and are infinitely more diverse and complex than carbohydrates and fats.
Below are just a few examples of important bodily proteins:
Enzymes (to run chemical reactions)
Peptide hormones (example: insulin)
Antibodies (immune system molecules)
Muscle fibers
Neurotransmitters (examples: serotonin, adrenaline, dopamine, nitrous oxide, and histamine)
Below are some examples of important molecules that cannot be built without proteins:
DNA and RNA
Glutathione (a critical antioxidant)
Creatine (supplies energy to muscles)
Why do we have to eat protein?
Carbohydrates, fats and cholesterol are made of carbon, hydrogen and oxygen, but proteins are unique because they also contain nitrogen. This is why the body cannot make protein out of carbohydrate, fat, or cholesterol. We can make carbohydrate (from protein), and can store some extra as glycogen. We can make cholesterol out of anything, and can recycle excess cholesterol in the bile. We can make most fats out of anything, and can store huge amounts of extra fat.
We can live a whole lifetime (after infancy) without eating any carbohydrate, and we can live for 6 months or more without eating any fat, depending on how much fat we have on our bodies to begin with. However, we have no way to store proteins and can only live for a maximum of 70 days without eating any protein.
Since we can’t make proteins from scratch, and we can’t store excess protein, protein is the only macronutrient that we absolutely must eat regularly in order to thrive. Without enough protein in the diet, the body will have no choice but to break down muscle fibers to release the protein it needs to survive.
What are amino acids?
Proteins are made up of small building blocks called amino acids. While there are hundreds of amino acids, there are only 20 amino acids used to build proteins. By combining these 20 amino acids in different sequences, cells can create thousands of unique proteins. Amino acids are like letters of the alphabet, and our cells put them together in different combinations like words in a dictionary, each one with its own meaning and purpose.
There are 9 essential (or indispensable) amino acids that we cannot make from scratch under any circumstances. We must eat all 9 of these amino acids regularly:
Histidine
Lysine
Threonine
Tryptophan
Leucine (branched)
Isoleucine (branched)
Valine (branched)
Methionine (contains sulfur; can be converted to cysteine)
Phenylalanine (can be converted to tyrosine)
*Branched chain amino acids are not metabolized by the liver; they are used primarily by muscle cells.
There are 5 “conditionally essential” amino acids that we need to eat under certain circumstances (growth, stress, illness):
Tyrosine
Cysteine
Glutamine
Arginine
Proline
There are 6 “nonessential” amino acids that we can make from other amino acids:
Asparagine
Alanine
Serine
Glycine
Aspartic acid
Glutamate
How much protein do I need?
This seems like such a simple question, but it isn’t . . .
According to the World Health Organization (WHO), the definition of the daily protein requirement is:
“the lowest level of dietary protein intake that will balance the losses of nitrogen from the body, and thus maintain the body protein mass, in persons at energy balance with modest levels of physical activity.”
However, the WHO also acknowledges that:
“this definition of the requirement in terms of nitrogen balance does not necessarily identify the optimal intake for health, which is less quantifiable.”
And, when it comes to exactly how much of each essential amino acid we need per day:
“At present, no method is entirely reliable for determining the dietary requirement for indispensable amino acids.”
We know that the human body goes through between 300 and 400 grams of protein every day, but that doesn’t necessarily mean that we have to eat 300 to 400 grams of protein every day; we can get most of that daily amount simply by recycling used proteins. We can’t recycle all of the proteins we eat, because some are wasted due to inefficiencies in metabolism, and some are lost through natural activities of daily living:
sloughing of skin cells
hair growth
DNA/RNA breakdown
undigested protein (eaten by bacteria in the colon)
sweat
urine ammonia (used to regulate pH of blood)
menstruation
semen
oxidation/gluconeogenesis (burning amino acids for energy)
Since we lose some protein every day, we have to eat protein to replace these losses. The Institute of Medicine (IOM) states that the minimum average daily protein intake for the average adult should be:
0.8 grams of protein per kg of body weight ~or~ 0.36 grams of protein per pound of body weight
For example, a 150-lb person would multiply 150 lbs x 0.36 grams of protein = 54 grams of protein per day. A simple way to do a rough calculation of the requirement in your head is to divide body weight by 3. It underestimates it a bit, but it’s very close.
Protein requirements, in grams of protein per pound of body weight:
0 to 6 mos: 0.69
7 to 12 mos: 0.54
Age 1 to 3: 0.48
Age 4 to 13: 0.43
Age 14 to 18: 0.39
Age 19 and older: 0.36
Pregnant women need additional protein to grow their babies:
1st trimester: + 0.5 gram per day
2nd trimester: + 8 gram per day
3rd trimester: + 25 gram per day
Breastfeeding mothers need additional protein for infant growth:
1st 6 mos: + 16 g/day (according to WHO)
2nd 6 mos: + 10 g/day (according to WHO)
[The IOM recommends adding 25 grams per day throughout lactation]
Adults with traumatic injuries (burns, major infections, head injuries, etc) need to temporarily increase protein intake for healing:
As for whether exercise increases dietary protein requirements:
“the question of how changes in energy flux through increased activity influence nitrogen balance may be of great practical importance. However, this important question is poorly understood.”
Common sense, though, would seem to indicate that building muscle should require additional protein.
Keep in mind that grams of protein do not equal grams of meat, because meat is not pure protein. For example:
a cooked chicken breast weighing 172 grams (6 ounces) contains 54 grams (just under 2 ounces) of protein
a cooked hamburger weighing 172 grams (6 ounces) contains 42 grams (1.5 ounces) of protein (beef contains less protein per ounce than chicken because beef contains more fat)
Do people eating low-carbohydrate diets need extra protein?
The standard scientific references (such as the WHO and the IOM) do not address this question, because protein requirement research is conducted on people eating standard diets, which usually contain a lot of carbohydrate. People who eat a standard diet make blood sugar out of the sugars and starches they eat. However, if you eat a very low carbohydrate diet, you will need to make blood glucose out of protein, instead, because we can only make very small amounts of glucose from fat. If you don’t eat enough protein to maintain your blood sugar, your body will steal protein from your muscles to accomplish this critical task. Therefore, people eating low-carbohydrate diets probably need to increase their protein intake to maintain healthy blood sugar levels without losing muscle.
What happens if I eat too much protein?
I find no evidence that exceeding your daily minimum protein requirements is dangerous to your health, so when in doubt, err on the side of eating more, not less. According to the Institute of Medicine, there is:
“no defined intake level at which potential adverse effects of protein was identified . . . [and] there is no evidence that amino acids from usual or even high intakes of protein from foodstuffs present any risk.”
Now, some of you may have heard that eating high-protein diets can cause illness, but the high protein diets referred to in these claims were not simply high in protein—they were also either too low in fat, too low in calories, too low in nutrients, or contained high amounts of foods that can be bothersome. There is no evidence that a diet high in animal protein AND fat is harmful.
Some of you may be familiar with the concept of “rabbit starvation”, which occurred when people tried to exist on a diet of only very lean rabbit meat, and became sick. This phenomenon is often cited as a reason not to eat a diet that contains too much animal protein. However, the problem with this diet was not the presence of too much animal protein; it was the absence of adequate fat:
“An exclusive diet of any lean meat, of which rabbit is a practical example, will cause digestive upset and diarrhea. Eating more and more rabbit, as one is impelled to do because of the increasing uneasiness of hunger, will only worsen the condition . The diarrhea and the general discomfort will not be relieved unless fat is added to the diet. Death will follow, otherwise, within a few days. One would probably be better off on just water than on rabbit and water.” [Angier]
When eating an all-animal diet, which is naturally extremely low in carbohydrate, the body must use fat for energy. The body also requires dietary fat to absorb vitamins and other nutrients from foods. There have been a number of cultures (Eskimos are a good example) which have thrived on nearly 100% animal food diets for centuries without any ill effects.
You may also have heard that eating too much protein can damage the kidney, but that is also not true. [For more information about this, see my meats page]
What does the body do with excess protein?
Any extra protein your body doesn’t need is turned into one of three things:
urea (urine)
glucose (blood sugar)
ammonia (urine)
When cells have extra protein they don’t need, they send it to the liver, where it is either turned into glucose or urea. Under standard conditions, 90% of excess protein is turned into urea (a non-toxic waste product) and excreted in the urine. The liver has a very high capacity for urea production and can handle up to 230 grams of protein at a time.
The fate of excess protein is determined by the hormonal state of the body.For example, if blood sugar is falling, glucagon and other hormones will turn on gluconeogenesisin the liver, which turns amino acids into glucose to maintain healthy blood sugar levels. All amino acids except for leucine and lysine can be turned into glucose [leucine and lysine can be turned into ketone bodies, instead, which most of the body’s cells can burn for energy]. When insulin levels are high, gluconeogenesis turns off, and the liver is asked to turn glucose into fat, so it is possible to turn excess amino acids into fat under those conditions.
It is possible for excess protein to cause an increase in blood sugar levels, however this potential varies from one person to the next, and the blood sugar elevations that do occur in some people are no match for the big spikes that can be caused by excess carbohydrates (especially refined and high glycemic index carbohydrates—see carbohydrates page).
Ammonia is another way for the body to get rid of protein, but it’s the least important way. Everyone has a small amount of ammonia in the blood, and most of this comes from bacteria in the colon. Bacteria break down undigested proteins in our food, excreting toxic ammonia as a by-product, which gets absorbed by our bloodstream. The liver quickly pulls this ammonia out of circulation so that the level stays very low. The kidneys are capable of generating ammonia, too, but they excrete it into the urine (as a way to regulate the acidity of the blood).
What is the difference between plant proteins and animal proteins?
Most plant foods contain less protein per ounce than animal foods.
Most plant foods are missing at least one of the nine essential amino acids (exceptions include soy and quinoa).
Plant foods tend to be lower in lysine, threonine, and the sulfur-containing amino acids cysteine and methionine. Wheat protein is particularly low in lysine. Corn is especially low in tryptophan. Legumes (including soybeans) are especially low in sulfur-containing amino acids.
Plant proteins are more likely to cause food allergy and sensitivity than proteins from most animal meats. Five of the top nine food allergens are plant proteins: gluten (a protein found in wheat and related grains), soy, corn, nuts, and peanuts [the other four being milk protein, egg protein, shellfish and fish].
Some plant proteins are less digestible (less bioavailable) than animal proteins. Protein from corn and beans are the least digestible, at about 70%, compared to meat, which is about 94% digestible. Glutens contain stretches of repetitive amino acid sequences (rich in proline and glutamine) that are particularly difficult for our enzymes to digest, so we cannot completely break this protein down into its individual amino acids. [Gutiérrez 2017]
Grains, beans, nuts, and seeds (the primary protein sources for plant-based diets) contain anti-nutrients including protease inhibitors which interfere with the body’s ability to digest proteins, and fiber which interferes with the absorption of protein. These plant protein sources also include phytic acid which interferes with mineral absorption. [See my grains, beans, nuts, and seeds page for more information about these anti-nutrients. See also my “Foods that Cause Hypothyroidism” article to read about the risk of goiter from eating soy.]
What happens if I don’t eat enough protein?
Protein deficiency is very uncommon in the developed world. Studies of vegans and vegetarians in the developed world find that they tend to get adequate amounts of protein in their diets. We used to think that vegans had to eat special combinations of plant foods at every meal to make sure they were getting all nine essential amino acids their bodies needed. However, we now know that the body can hold on to amino acids for several hours, so, as long as vegans are getting all nine essential amino acids in their diet at some point during the day, they don’t have to worry about eating them simultaneously at every meal. However, vegans must be careful to eat a variety of plant protein sources in order to obtain all necessary amino acids. If rice, corn, or wheat is the SOLE source of dietary protein, essential amino acid requirements will not be satisfied.
Unfortunately, protein deficiency is a very common cause of malnutrition in underdeveloped countries. Protein malnutrition stunts growth, reduces immune function and increases susceptibility to infection.
Third-world diets are often too low in calories of all kinds, not just protein calories. Inadequate calorie intake can lead to burning of proteins for energy instead of using them to make important body molecules.
Third-world diets are often poor in essential vitamins which are needed to properly build, utilize, and recycle proteins.
Third-world diets are often very high in plant foods, because they are less expensive than animal foods. Many plant foods contain “protease inhibitors” which interfere with the body’s ability to digest proteins, and fiber itself interferes with the absorption of protein.
Bottom line about protein
We must eat high quality sources of proteins regularly because we cannot make them from scratch and we cannot store them.
Animal sources of protein are ideal, because they contain all 20 of the amino acids our cells use to build proteins, and because they are easier to digest and absorb. However, a carefully planned vegan diet can provide adequate amounts of protein.
Growing children/teens, pregnant/breastfeeding women, people with traumatic injuries or severe infections, and people eating a low-carbohydrate diet have higher protein requirements than the average person.
There is no evidence that eating protein in excess of estimated daily requirements is harmful to health.
Pencharz PB, Young VR. Protein and amino acids. In: Bowman B, Russell R, eds. Present Knowledge in Nutrition. 9th edition. Washington DC: International Life Sciences Institute; 2006.
Joint FAO/WHO/UNU Expert Consultation on Protein and Amino Acid Requirements in Human Nutrition. WHO Technical Report Series 935. Geneva, Switzerland: WHO; 2002.
All animals must eat protein regularly to survive, because we cannot make protein out of fat or carbohydrate or cholesterol. Proteins form enzymes, muscles, hormones, and other vital bodily components. How much protein do we need, and does it matter where we get it from?
What is protein?
Proteins are complicated molecules of many different shapes and sizes that are essential to all forms of life. Proteins are intimately involved in virtually everything that happens inside our cells and are infinitely more diverse and complex than carbohydrates and fats.
Below are just a few examples of important bodily proteins:
Enzymes (to run chemical reactions)
Peptide hormones (example: insulin)
Antibodies (immune system molecules)
Muscle fibers
Neurotransmitters (examples: serotonin, adrenaline, dopamine, nitrous oxide, and histamine)
Below are some examples of important molecules that cannot be built without proteins:
DNA and RNA
Glutathione (a critical antioxidant)
Creatine (supplies energy to muscles)
Why do we have to eat protein?
Carbohydrates, fats and cholesterol are made of carbon, hydrogen and oxygen, but proteins are unique because they also contain nitrogen. This is why the body cannot make protein out of carbohydrate, fat, or cholesterol. We can make carbohydrate (from protein), and can store some extra as glycogen. We can make cholesterol out of anything, and can recycle excess cholesterol in the bile. We can make most fats out of anything, and can store huge amounts of extra fat.
We can live a whole lifetime (after infancy) without eating any carbohydrate, and we can live for 6 months or more without eating any fat, depending on how much fat we have on our bodies to begin with. However, we have no way to store proteins and can only live for a maximum of 70 days without eating any protein.
Since we can’t make proteins from scratch, and we can’t store excess protein, protein is the only macronutrient that we absolutely must eat regularly in order to thrive. Without enough protein in the diet, the body will have no choice but to break down muscle fibers to release the protein it needs to survive.
What are amino acids?
Proteins are made up of small building blocks called amino acids. While there are hundreds of amino acids, there are only 20 amino acids used to build proteins. By combining these 20 amino acids in different sequences, cells can create thousands of unique proteins. Amino acids are like letters of the alphabet, and our cells put them together in different combinations like words in a dictionary, each one with its own meaning and purpose.
There are 9 essential (or indispensable) amino acids that we cannot make from scratch under any circumstances. We must eat all 9 of these amino acids regularly:
Histidine
Lysine
Threonine
Tryptophan
Leucine (branched)
Isoleucine (branched)
Valine (branched)
Methionine (contains sulfur; can be converted to cysteine)
Phenylalanine (can be converted to tyrosine)
*Branched chain amino acids are not metabolized by the liver; they are used primarily by muscle cells.
There are 5 “conditionally essential” amino acids that we need to eat under certain circumstances (growth, stress, illness):
Tyrosine
Cysteine
Glutamine
Arginine
Proline
There are 6 “nonessential” amino acids that we can make from other amino acids:
Asparagine
Alanine
Serine
Glycine
Aspartic acid
Glutamate
How much protein do I need?
This seems like such a simple question, but it isn’t . . .
According to the World Health Organization (WHO), the definition of the daily protein requirement is:
“the lowest level of dietary protein intake that will balance the losses of nitrogen from the body, and thus maintain the body protein mass, in persons at energy balance with modest levels of physical activity.”
However, the WHO also acknowledges that:
“this definition of the requirement in terms of nitrogen balance does not necessarily identify the optimal intake for health, which is less quantifiable.”
And, when it comes to exactly how much of each essential amino acid we need per day:
“At present, no method is entirely reliable for determining the dietary requirement for indispensable amino acids.”
We know that the human body goes through between 300 and 400 grams of protein every day, but that doesn’t necessarily mean that we have to eat 300 to 400 grams of protein every day; we can get most of that daily amount simply by recycling used proteins. We can’t recycle all of the proteins we eat, because some are wasted due to inefficiencies in metabolism, and some are lost through natural activities of daily living:
sloughing of skin cells
hair growth
DNA/RNA breakdown
undigested protein (eaten by bacteria in the colon)
sweat
urine ammonia (used to regulate pH of blood)
menstruation
semen
oxidation/gluconeogenesis (burning amino acids for energy)
Since we lose some protein every day, we have to eat protein to replace these losses. The Institute of Medicine (IOM) states that the minimum average daily protein intake for the average adult should be:
0.8 grams of protein per kg of body weight ~or~ 0.36 grams of protein per pound of body weight
For example, a 150-lb person would multiply 150 lbs x 0.36 grams of protein = 54 grams of protein per day. A simple way to do a rough calculation of the requirement in your head is to divide body weight by 3. It underestimates it a bit, but it’s very close.
Protein requirements, in grams of protein per pound of body weight:
0 to 6 mos: 0.69
7 to 12 mos: 0.54
Age 1 to 3: 0.48
Age 4 to 13: 0.43
Age 14 to 18: 0.39
Age 19 and older: 0.36
Pregnant women need additional protein to grow their babies:
1st trimester: + 0.5 gram per day
2nd trimester: + 8 gram per day
3rd trimester: + 25 gram per day
Breastfeeding mothers need additional protein for infant growth:
1st 6 mos: + 16 g/day (according to WHO)
2nd 6 mos: + 10 g/day (according to WHO)
[The IOM recommends adding 25 grams per day throughout lactation]
Adults with traumatic injuries (burns, major infections, head injuries, etc) need to temporarily increase protein intake for healing:
As for whether exercise increases dietary protein requirements:
“the question of how changes in energy flux through increased activity influence nitrogen balance may be of great practical importance. However, this important question is poorly understood.”
Common sense, though, would seem to indicate that building muscle should require additional protein.
Keep in mind that grams of protein do not equal grams of meat, because meat is not pure protein. For example:
a cooked chicken breast weighing 172 grams (6 ounces) contains 54 grams (just under 2 ounces) of protein
a cooked hamburger weighing 172 grams (6 ounces) contains 42 grams (1.5 ounces) of protein (beef contains less protein per ounce than chicken because beef contains more fat)
Do people eating low-carbohydrate diets need extra protein?
The standard scientific references (such as the WHO and the IOM) do not address this question, because protein requirement research is conducted on people eating standard diets, which usually contain a lot of carbohydrate. People who eat a standard diet make blood sugar out of the sugars and starches they eat. However, if you eat a very low carbohydrate diet, you will need to make blood glucose out of protein, instead, because we can only make very small amounts of glucose from fat. If you don’t eat enough protein to maintain your blood sugar, your body will steal protein from your muscles to accomplish this critical task. Therefore, people eating low-carbohydrate diets probably need to increase their protein intake to maintain healthy blood sugar levels without losing muscle.
What happens if I eat too much protein?
I find no evidence that exceeding your daily minimum protein requirements is dangerous to your health, so when in doubt, err on the side of eating more, not less. According to the Institute of Medicine, there is:
“no defined intake level at which potential adverse effects of protein was identified . . . [and] there is no evidence that amino acids from usual or even high intakes of protein from foodstuffs present any risk.”
Now, some of you may have heard that eating high-protein diets can cause illness, but the high protein diets referred to in these claims were not simply high in protein—they were also either too low in fat, too low in calories, too low in nutrients, or contained high amounts of foods that can be bothersome. There is no evidence that a diet high in animal protein AND fat is harmful.
Some of you may be familiar with the concept of “rabbit starvation”, which occurred when people tried to exist on a diet of only very lean rabbit meat, and became sick. This phenomenon is often cited as a reason not to eat a diet that contains too much animal protein. However, the problem with this diet was not the presence of too much animal protein; it was the absence of adequate fat:
“An exclusive diet of any lean meat, of which rabbit is a practical example, will cause digestive upset and diarrhea. Eating more and more rabbit, as one is impelled to do because of the increasing uneasiness of hunger, will only worsen the condition . The diarrhea and the general discomfort will not be relieved unless fat is added to the diet. Death will follow, otherwise, within a few days. One would probably be better off on just water than on rabbit and water.” [Angier]
When eating an all-animal diet, which is naturally extremely low in carbohydrate, the body must use fat for energy. The body also requires dietary fat to absorb vitamins and other nutrients from foods. There have been a number of cultures (Eskimos are a good example) which have thrived on nearly 100% animal food diets for centuries without any ill effects.
You may also have heard that eating too much protein can damage the kidney, but that is also not true. [For more information about this, see my meats page]
What does the body do with excess protein?
Any extra protein your body doesn’t need is turned into one of three things:
urea (urine)
glucose (blood sugar)
ammonia (urine)
When cells have extra protein they don’t need, they send it to the liver, where it is either turned into glucose or urea. Under standard conditions, 90% of excess protein is turned into urea (a non-toxic waste product) and excreted in the urine. The liver has a very high capacity for urea production and can handle up to 230 grams of protein at a time.
The fate of excess protein is determined by the hormonal state of the body.For example, if blood sugar is falling, glucagon and other hormones will turn on gluconeogenesisin the liver, which turns amino acids into glucose to maintain healthy blood sugar levels. All amino acids except for leucine and lysine can be turned into glucose [leucine and lysine can be turned into ketone bodies, instead, which most of the body’s cells can burn for energy]. When insulin levels are high, gluconeogenesis turns off, and the liver is asked to turn glucose into fat, so it is possible to turn excess amino acids into fat under those conditions.
It is possible for excess protein to cause an increase in blood sugar levels, however this potential varies from one person to the next, and the blood sugar elevations that do occur in some people are no match for the big spikes that can be caused by excess carbohydrates (especially refined and high glycemic index carbohydrates—see carbohydrates page).
Ammonia is another way for the body to get rid of protein, but it’s the least important way. Everyone has a small amount of ammonia in the blood, and most of this comes from bacteria in the colon. Bacteria break down undigested proteins in our food, excreting toxic ammonia as a by-product, which gets absorbed by our bloodstream. The liver quickly pulls this ammonia out of circulation so that the level stays very low. The kidneys are capable of generating ammonia, too, but they excrete it into the urine (as a way to regulate the acidity of the blood).
What is the difference between plant proteins and animal proteins?
Most plant foods contain less protein per ounce than animal foods.
Most plant foods are missing at least one of the nine essential amino acids (exceptions include soy and quinoa).
Plant foods tend to be lower in lysine, threonine, and the sulfur-containing amino acids cysteine and methionine. Wheat protein is particularly low in lysine. Corn is especially low in tryptophan. Legumes (including soybeans) are especially low in sulfur-containing amino acids.
Plant proteins are more likely to cause food allergy and sensitivity than proteins from most animal meats. Five of the top nine food allergens are plant proteins: gluten (a protein found in wheat and related grains), soy, corn, nuts, and peanuts [the other four being milk protein, egg protein, shellfish and fish].
Some plant proteins are less digestible (less bioavailable) than animal proteins. Protein from corn and beans are the least digestible, at about 70%, compared to meat, which is about 94% digestible. Glutens contain stretches of repetitive amino acid sequences (rich in proline and glutamine) that are particularly difficult for our enzymes to digest, so we cannot completely break this protein down into its individual amino acids. [Gutiérrez 2017]
Grains, beans, nuts, and seeds (the primary protein sources for plant-based diets) contain anti-nutrients including protease inhibitors which interfere with the body’s ability to digest proteins, and fiber which interferes with the absorption of protein. These plant protein sources also include phytic acid which interferes with mineral absorption. [See my grains, beans, nuts, and seeds page for more information about these anti-nutrients. See also my “Foods that Cause Hypothyroidism” article to read about the risk of goiter from eating soy.]
What happens if I don’t eat enough protein?
Protein deficiency is very uncommon in the developed world. Studies of vegans and vegetarians in the developed world find that they tend to get adequate amounts of protein in their diets. We used to think that vegans had to eat special combinations of plant foods at every meal to make sure they were getting all nine essential amino acids their bodies needed. However, we now know that the body can hold on to amino acids for several hours, so, as long as vegans are getting all nine essential amino acids in their diet at some point during the day, they don’t have to worry about eating them simultaneously at every meal. However, vegans must be careful to eat a variety of plant protein sources in order to obtain all necessary amino acids. If rice, corn, or wheat is the SOLE source of dietary protein, essential amino acid requirements will not be satisfied.
Unfortunately, protein deficiency is a very common cause of malnutrition in underdeveloped countries. Protein malnutrition stunts growth, reduces immune function and increases susceptibility to infection.
Third-world diets are often too low in calories of all kinds, not just protein calories. Inadequate calorie intake can lead to burning of proteins for energy instead of using them to make important body molecules.
Third-world diets are often poor in essential vitamins which are needed to properly build, utilize, and recycle proteins.
Third-world diets are often very high in plant foods, because they are less expensive than animal foods. Many plant foods contain “protease inhibitors” which interfere with the body’s ability to digest proteins, and fiber itself interferes with the absorption of protein.
Bottom line about protein
We must eat high quality sources of proteins regularly because we cannot make them from scratch and we cannot store them.
Animal sources of protein are ideal, because they contain all 20 of the amino acids our cells use to build proteins, and because they are easier to digest and absorb. However, a carefully planned vegan diet can provide adequate amounts of protein.
Growing children/teens, pregnant/breastfeeding women, people with traumatic injuries or severe infections, and people eating a low-carbohydrate diet have higher protein requirements than the average person.
There is no evidence that eating protein in excess of estimated daily requirements is harmful to health.
Pencharz PB, Young VR. Protein and amino acids. In: Bowman B, Russell R, eds. Present Knowledge in Nutrition. 9th edition. Washington DC: International Life Sciences Institute; 2006.
Joint FAO/WHO/UNU Expert Consultation on Protein and Amino Acid Requirements in Human Nutrition. WHO Technical Report Series 935. Geneva, Switzerland: WHO; 2002.
From the 1970’s until very recently, we were told that all fats were bad, and we should eat as little fat as possible. We now know that polyunsaturated omega-3 fatty acids are not only good for us, they are essential. What is the difference between saturated and unsaturated fats? Are some fats “good” and other fats “bad”?
What is fat?
Fats and oils are large molecules made of carbon, hydrogen, and a little bit of oxygen. Each fat molecule contains 3 fatty acid tails attached to a glycerol backbone. The result is called a “triglyceride.” Every fat molecule (or triglyceride) has the same glycerol backbone; it’s the different types of fatty acids attached to that backbone that give different kinds of fats their unique properties. Each fatty acid is essentially a long chain of carbon atoms with lots of hydrogen atoms attached to it along both sides, and an “acid” group on one end.
Fat is good.
We think of fat as bad; as something we want to get rid of. We think that the less we have of it the healthier we are. When we have too much of it, we feel ugly and unhappy. But the truth is that fat is incredibly important. Fat is vital to human life and health.
Fat is our portable battery pack.
Fat is an efficient, lightweight, flexible, and portable source of energy. All animals store energy as fat for these reasons. If we were meant to burn carbohydrates for energy, we would have the ability to sprout big lumps of starch all over our bodies, the way plants do. But Mother Nature is smart. She knows that animals need to move around in the world and can’t afford to be weighed down by heavy potato-like structures. Our bodies can only store hours’ worth of energy as starch (glycogen), but we can store months’ worth of energy as fat.
Fat contains more than twice the amount of energy per pound than carbohydrates do. You probably already know this but may not have thought about it this way: carbohydrate contains 4 calories per gram and fat contains 9 calories per gram. Calories are units of energy. Fat can pack a lot more energy than starch can.
Saturated fat is the preferred fuel of the heart, which is why the heart has some saturated fat wrapped around it.
Our brains are mostly made of fat.
Approximately 60% of the brain is made out of fat. In addition to being an important component of every brain cell membrane, fat also is a major component of myelin, the special insulating material that is wrapped around the electrical wiring pathways of our brain (damage to myelin is the hallmark of Multiple Sclerosis). Myelin is approximately 50% fat and 50% cholesterol.
Fat protects us.
Fat cushions our delicate vital organs so they won’t be bruised or damaged when we run, jump, or fall. Fat is a critical component of our skin—the barrier between us and the outside world—preventing us from randomly absorbing everything we come into contact with. Fats are integral parts of the outer lining (membrane) of every cell in our bodies, forming a water-tight seal that keeps stuff that should be inside the cell inside and stuff that should stay outside of the cell outside. What’s more, inside each cell are mini-compartments, like the nucleus and the mitochondria, that need to keep their contents separate from the inside of the rest of the cell, so they each have fatty membranes, as well.
Fats lubricate our moving parts.
Fats are important ingredients in tears, joint fluids, and other slippery substances that we need to function properly.
Dietary fat is required for vitamin absorption.
Certain essential vitamins, such as A, D, E and K, all require fat in order to be absorbed by our intestines. Fat itself is so important to our health and survival, that we are designed to absorb about 99% of all the fat we eat. This is not true of many plant substances that we think of as so important to our health, such as vegetable iron and beta-carotene.
How much fat do we need to eat?
This is a difficult question. Fat is so important to every cell in our bodies that we can make fat out of anything—we can make it out of dietary proteins from animals and plants, and we can make it out of carbohydrates, like sugar and starch. That doesn’t mean that these are the ideal ways to obtain fats—for all we know, the body would prefer to get its fat directly from the diet so that it doesn’t have to go through the hassle of turning other dietary ingredients into fat—it just means that it’s possible. There are only a few fats (essential fatty acids) that we absolutely must eat because we can’t make them ourselves (see below).
What is the difference between saturated and unsaturated fat?
A saturated fatty acid has the most hydrogen atoms it can possibly carry—it is therefore “saturated” with hydrogen. Every carbon atom is attached to as many hydrogen atoms as it can hold. Each carbon-hydrogen bond carries energy, so the more hydrogen atoms that are bound to a fat, the more energy you can get out of that fat when you burn it. Saturated fat has more energy, and therefore more calories, per pound.
Unsaturated fats have less hydrogen—at least one of the carbons will have a hydrogen missing. Since there is no hydrogen for that carbon to bind to, the carbon atom forms a double bond to a neighboring carbon atom instead. If a fat has one double bond, it is called “monounsaturated” (missing one hydrogen). Oleic acid, the primary fatty acid in olive oil, is a well-known example of a monounsaturated fatty acid, or MUFA. If it has more than one double bond, it is called “polyunsaturated” (missing more than one hydrogen). Omega-3 and omega-6 fatty acids (see below) are well-known examples of polyunsaturated fatty acids, or PUFAs.
Most fats occurring in nature contain mixtures of saturated, monounsaturated, and polyunsaturated fatty acids. Olive oil contains approximately 17% saturated fatty acids, 71% MUFA (oleic acid), and 11% PUFAs. Coconut oil contains more than 90% saturated fat. Beef fat contains nearly equal parts saturated fat and monounsaturated fat (most of which is oleic acid, the primary fatty acid in olive oil) and approximately 5% polyunsaturated fat, depending on what the animal is fed.
Saturated fats, with their full load of energy-packed hydrogen bonds, are straight molecules that stack together efficiently, and are therefore solid at room temperature (like lard, cocoa butter and coconut oil). Unsaturated fats, with their weaker double bonds, are crooked, because double bonds create kinks in the backbone. They do not pack together efficiently and are therefore liquid at room temperature (like olive oil). Imagine a box full of straight straws—they pack easily and you can fit a lot of straws into the box. However you can’t fit as many bendy straws into that same box because they take up more space. They also move around more inside the box.
When molecules have room to move around easily, they are more likely to form liquids than solids. Saturated fats are very stable, whereas unsaturated fats (oils) are fragile. The carbon double bonds in unsaturated fats are weak and vulnerable to chemical attack compared to the strong carbon-hydrogen bonds in saturated fats. This is why unsaturated fats (oils) go rancid (become oxidized) when exposed to air, whereas you can leave lard or butter on the countertop for a long time without worrying about it. Ghee, which is butter with all of its proteins removed (pure butterfat), can be stored at room temperature indefinitely.
Are saturated fats unhealthy?
Our bodies need both types of fats—saturated and unsaturated. Saturated fats are good for things like insulation (myelin), cushioning (abdominal fat around our organs), and storage (body fat under the skin) purposes. Unsaturated fats are good for flexibility and fluidity purposes, such as in membranes and body fluids. It doesn’t make sense to think of one kind as inherently healthy and the other kind as inherently unhealthy.
Saturated fats are chemically rather boring—they are quite stable (especially as compared to the reactive PUFAs) and it is hard from a common sense point of view to imagine them causing the kinds of trouble they are accused of causing—such as burrowing into heart vessel walls and causing inflammatory plaques that rupture into heart attacks. These are by nature long, smooth, non-irritating substances.
You would not want all of your body fat to be unsaturated. All of your fat would be liquid instead of firm and compact. Not only would you sag everywhere, and begin to resemble a Shar Pei, but your body would have to be bigger, because liquid fats take up more space (like the bent straws in the box).
The misguided belief that saturated fats cause heart disease is rooted in a famous study published in 1970 called “The Seven Countries Study,” in which renowned scientist Ancel Keys claimed that people in countries where more animal fat was eaten had more heart disease then people in countries where less animal fat was eaten. Not only was this study an epidemiological study, and therefore incapable of proving a causal link between any dietary factor and any disease, but there have been numerous studies showing no connection at all between saturated fat and heart disease, including a study of 22 countries published by Yerushalmy and Hilleboe in 1957 (see references below).
The hypothesis that saturated fat causes heart disease now stands on very shaky ground; it is now controversial at best, if not obsolete. Researchers are finding much stronger evidence linking cholesterol dysregulation and heart disease to refined carbohydrates than to saturated fats [Halton 2006, Howard 2006, Mente 2009, Astrup 2010, and Jakobsen 2010].
What are omega-3 fatty acids?
Omega-3 fatty acids are polyunsaturated fatty acids (PUFAs). This means they each have more than one carbon double bond in place of a hydrogen atom. Omega-3 just means that the first double bond in the fat chain is at carbon #3 in the backbone. They are liquid fats (oils).
Even if you eat a 100% fat-free diet, your body will find a way to make almost all of the important fats it needs out of the protein and carbohydrate you eat, but it cannot make omega-3 fatty acids. There are three omega-3 fatty acids that are often called “essential” to our health: ALA (alpha-linolenic acid), EPA (eicosapentaenoic acid), and DHA (docosahexaenoic acid). Because we can’t make them from scratch, we have to eat them.
What is ALA?
ALA is the mother of all omega-3 fatty acids. It is an 18-carbon fatty acid that we can build upon to make EPA (20 carbons), which can in turn be converted to DHA (22 carbons). This process happens in the liver. The problem is that our bodies are not very good at adding carbons to ALA, so we convert only a very small percentage (less than 5%) of the ALA we eat into EPA, and far less of that EPA into DHA. So, the vast majority of the ALA we eat does not turn into precious EPA and DHA; it simply gets burned for energy or stored as fat.
It appears as if ALA itself isn’t required by the body as an important component of any particular cell or molecule; it may only be important as a building block for EPA and DHA. Therefore, if you get enough EPA and DHA in your diet, you may not need any ALA.
What are EPA and DHA?
EPA and DHA, on the other hand, serve important roles in the body. I mention them together because they are almost always found together in nature, and because researchers almost always study them in combination, not individually. Therefore, it can be confusing to try to figure out which one of these compounds is responsible for which benefits. Both EPA and DHA serve as building blocks for anti-inflammatory, pro-healing compounds called “resolvins” and “protectins”, which help to prevent chronic inflammation. They also stabilize the electrical activity of cardiac cell membranes, reducing risk of arrhythmias.
It seems as if DHA may be the most essential of the essential omega-3 fatty acids. The brain and retina require large amounts of DHA for their cells to function properly. It is found in the cell membranes of the brain and retina, helping to keep those membranes fluid and flexible. This is important, because membranes don’t simply act as water-tight walls. They have to be able to wrap around and envelop important nutrients to take them in, or fold outward to let them out. Membranes are very dynamic structures. [I wrote an entire post about the critical role of DHA in the brain and how to include it in your diet in my Psychology Today post: “The Brain Needs Animal Fat.”]
What are good dietary sources of ALA?
ALA is easy to obtain because it is found in such a wide variety of plant and animal foods. Interestingly, Americans obtain more of their daily ALA from animal foods than from plant foods. Oils of seeds, grains, nuts, and legumes contain ALA, with the highest concentrations being found in flaxseed oil, walnuts, canola oil and chia seeds. These foods are therefore marketed as being “rich in omega-3s.” There is also a significant amount of ALA in purslane, an edible succulent green vegetable, and small amounts of ALA in spinach leaves.
The problem is that these sources only contain one of the three essential omega-3 fatty acids; they do not contain any DHA or EPA. And the body can only convert a very small percentage of ALA into EPA (3-8%) and has an even harder time converting ALA into DHA (0-4%), although there are some studies that suggest that, in the complete absence of dietary DHA (such as may occur for vegans), the body may be able to ramp up its ability to convert ALA into DHA to some extent.
What are good dietary sources of EPA and DHA?
EPA and DHA are synthesized primarily by algae and grasses—things that people don’t eat and don’t digest well:
Marine microalgae
Seaweed
Grasses
However, many land animals eat grasses (or should) and many fish (especially small fish) eat algae. Animals eating these green foods accumulate EPA and DHA in their tissues, especially in their fats, livers, and brains. Therefore, good sources of EPA and DHA include:
Meat from grass-fed animals
Liver from grass-fed animals (much higher amounts than muscle meats)
Pasture-raised poultry meat
Liver from pasture-raised poultry (much higher amounts than bird meat)
Animal brain
Small oily fish (anchovy, herring, sardines and mackerel)
Large oily fish that eat small oily fish (bluefish, tuna, salmon, halibut, bass, and trout)—even farmed fish often contain omega-3’s because of what they are fed.
Fish liver oils, such as cod liver oil.
Oysters
Eggs from pastured poultry contain some DHA but are a poor source of EPA.
Full-fat dairy products, especially from grass-fed animals, contain some EPA but are a poor source of DHA.
What are omega-6 fatty acids?
Omega-6 fatty acids are liquid polyunsaturated fatty acids (PUFAs) just like omega-3s are, but they have their first double bond at carbon #6 instead of carbon #3. Whereas there are three important omega-3 fatty acids for human health, there is only one essential omega-6 fatty acid: linoleic acid (LA).
What is linoleic acid (LA)?
It is so unfortunate that linoleic acid, the mother of all omega-6 fatty acids, and alpha-linolenic acid, the mother of all omega-3 fatty acids, have such similar names, because many people confuse the two, but so be it. LA is an 18-carbon polyunsaturated omega-6 fatty acid that we can build upon to make other important molecules, most notably, a 20-carbon omega-6 fatty acid called arachidonic acid.
Linoleic acid is present in all of our cell membranes so that it will be available to form arachidonic acid whenever called upon to do so. Arachidonic acid is required for the process of inflammation to begin. You might be thinking that inflammation is a bad thing, but without it, we cannot mount an immune response to things like bacterial infections and physical injuries. Inflammation is our first line of defense and requires specialized molecules that are made from arachidonic acid: prostaglandins, leukotrienes, and thromboxanes.
While you may not have heard of any of those inflammatory chemicals, you have probably heard of the medicines that are marketed to reduce their activity. NSAIDs such as ibuprofen reduce prostaglandin synthesis. Aspirin reduces prostaglandin synthesis and thromboxane activity. Singulair® is an asthma medication that reduces leukotriene activity.
Do You Have Arachiphobia?
I wrote an entire post for Psychology Today dedicated to busting the nutrition myth that arachidonic acid is dangerously inflammatory for our system: “Do You Have Arachiphobia?” Written as a personal testimony of a misunderstood fatty acid that deserves our respect, it is a fun piece that details the numerous critical functions of this important nutrient.
What are good dietary sources of Linoleic Acid?
Our Western diet is loaded with LA, so not to worry. In fact, we get far more LA than we need. Linoleic acid is present in all kinds of plant and animal foods, but it is present in especially high amounts in vegetable oils (nut and seed oils). Animal fats contain approximately 10-20 % LA, whereas seed oils contain between 50-80% LA. We have been told for decades to avoid animal fats and to choose plant oils instead, and the result is that most of us now get far too much LA in our diet.
The omega ratio problem: are you off-balance?
So, the omega-3 fatty acids are used to create chemicals that have anti-inflammatory properties (resolvins, protectins) and the omega-6 fatty acid LA is used primarily to create chemicals that have pro-inflammatory properties (prostaglandins, leukotrienes, and thromboxanes).
All creatures need a proper balance of these two forces in order to defend themselves (pro-inflammatory elements) and heal (anti-inflammatory elements). Mother Nature understood this, which is why we are gifted with both pathways. In fact, these pathways are intricately connected to each other to keep one another in check. It’s a brilliant system. The pathway that leads from the omega-3 ALA to EPA and DHA uses the very same enzymes as the pathway leading from the omega-6 LA to arachidonic acid. The omega-3 and omega-6 pathways have to share these enzymes, so the pathways actually compete with one another.
This is why some scientists believe that it is important to eat a balance of omega-3 and omega-6 fatty acids. There is good evidence to suggest that our ancestors ate diets that contained roughly equal amounts of omega-3 and omega-6, depending on where they lived; at most their diets may have had 2 to 4 times more omega-6 than omega-3. However, these days our diets contain 20 to 30 times more omega-6 than omega-3, tipping the scale mightily toward inflammation and away from healing. This may be one of the most important reasons why so many people experience chronic pain and inflammation and find themselves turning so often to medications like ibuprofen to turn down the activity of the omega-6 pathway.
The same problem occurs in animals. Grass is high in ALA, the omega-3 parent molecule, whereas grains are high in LA, the omega-6 parent molecule. Therefore, grain-fed cows, for example, have an excess of omega-6 fatty acids and a deficit of omega-3 fatty acids. Grass-fed beef has an average omega-6 to omega-3 ratio of 1.53 to 1, whereas grain-fed beef has a ratio of 7.65 to 1.
If you don’t regularly eat foods naturally rich in omega-3, you should consider taking a supplement. There are three forms of omega-3 fatty acids: ALA, EPA and DHA, and supplements vary greatly in quantities of each form. Aim for about 1000 mg of EPA + DHA (combined—not 1000 mg of each) per day. An example of a good choice for fish oil is Nordic Naturals Ultimate Omega. An example of a good choice for an algae-derived vegetarian/vegan-friendly omega-3 supplement is NuTru Vegan Omega 3 EPA+DHA. [I do not have financial relationships with either of these manufacturers]
Fish oil Supplement
Vegan Supplement
Is it possible to eat too much omega-3?
Theoretically, yes. If you ate a diet consisting only of a high-omega-3 fish, such as mackerel or salmon, your omega-6 intake would be very low in comparison to your omega-3, and it is possible that your ratio could turn upside-down. Would that be bad for your health? The theoretical possibilities include increased risk of bleeding and reduced ability to mount an appropriate inflammatory response to injuries and infections. I found two studies that can help us to address this question.
In the first study [Siess et al 1980], researchers fed men a diet consisting of unlimited carbohydrate + mackerel for one week, so that mackerel was the only source of fat or protein. This diet provided 7 to 11 grams of omega-3 fatty acids per day. The number of platelets (blood clotting bodies) in the blood of these men was reduced and platelets were less sticky in laboratory tests compared to platelets of those eating a standard diet. The authors of the study concluded that these were healthy developments, because they could potentially decrease the risk of blood clots in people who are at risk for strokes and heart attacks.
In the second study, researchers compared one diet containing essentially no omega-3 fatty acids, to another diet containing 10 grams per day of omega-3 fatty acids in the form of salmon and salmon oil. After 3 weeks, in the high omega-3 group, platelet counts dropped (in a couple of cases to below normal–the lowest count was 90,000, whereas the normal lower limit is considered to be 150,000), platelets became less sticky, and bleeding time was lengthened to about 10 minutes on average (normal upper limit considered to be about 9 minutes). The authors did not conclude whether these findings meant that the high omega-3 diet was healthier or riskier than the omega-3 free diet.
The typical recommended dose of omega-3 fatty acids is between 1 and 2 grams per day. Since the scientific jury is still out about the potential risks involved in taking very high doses of omega- 3, it would be best to use common sense here. It is nearly impossible to eat a natural diet that is too high in omega-3 and too low in omega-6. However, eating a diet of 100% oily fish (there are no studies of such a diet) or taking very high doses of omega-3 fatty acids could theoretically throw your ratio off-balance to the point that bleeding and resistance to infection could become problematic.
Bottom line about fats
Healthy fats are healthy for you.
Include healthy animal fats in your daily diet if you can, as these are naturally good sources of EPA and DHA.
Reduce the amount of vegetable oils (nut and seed oils) in your diet to improve your omega-3 to omega-6 ratio.
If you choose to eat a vegan diet, be sure to include some DHA/EPA from microalgae sources, and gravitate towards plant foods that are high in ALA and low in LA.
To learn why dietary cholesterol is not bad for you, read my cholesterol page.
21 Day Sugar Detox
21 Day Sugar Detox
Insoluble fiber is affectionately called “roughage.” Insoluble fiber is called insoluble because it does not dissolve in water. It is the stuff that gives tree bark, nutshells and twigs their woody texture. Foods high in insoluble fiber include grains, seeds, nuts, vegetables and certain fruits. Insoluble fibers pass through our digestive system practically untouched, because even bacteria can’t easily digest them. We are told that insoluble fiber is good for us because it adds weighty “bulk” to the contents of our intestines, helping to push things along. Why expose the smooth inner surfaces of our intestines to these abrasive indigestibles? We are told that we need them to sweep our innards clean of potential toxins. Oddly enough, I was unable to locate a single scientific article explaining what these toxins are and how insoluble fiber removes them . . . therefore this must simply be a common belief—an appealing image that makes sense in our minds, but that has absolutely no science behind it.
The biggest difference between soluble fiber and insoluble fiber is that it is, as the name implies, soluble in water—it can partially dissolve in water. Most over-the-counter laxatives are made with soluble fiber. Soluble fiber dissolves partially in water, forming a gel—you can see this happen when you stir a soluble fiber supplement such as Metamucil® into a glass of water. The ability of soluble fiber to hold water is what allows fruits and soft vegetable parts to contain water and yet maintain their firm shape.
Insoluble fiber is affectionately called “roughage.” Insoluble fiber is called insoluble because it does not dissolve in water. It is the stuff that gives tree bark, nutshells and twigs their woody texture. Foods high in insoluble fiber include grains, seeds, nuts, vegetables and certain fruits. Insoluble fibers pass through our digestive system practically untouched, because even bacteria can’t easily digest them. We are told that insoluble fiber is good for us because it adds weighty “bulk” to the contents of our intestines, helping to push things along. Why expose the smooth inner surfaces of our intestines to these abrasive indigestibles? We are told that we need them to sweep our innards clean of potential toxins. Oddly enough, I was unable to locate a single scientific article explaining what these toxins are and how insoluble fiber removes them . . . therefore this must simply be a common belief—an appealing image that makes sense in our minds, but that has absolutely no science behind it.
The biggest difference between soluble fiber and insoluble fiber is that it is, as the name implies, soluble in water—it can partially dissolve in water. Most over-the-counter laxatives are made with soluble fiber. Soluble fiber dissolves partially in water, forming a gel—you can see this happen when you stir a soluble fiber supplement such as Metamucil® into a glass of water. The ability of soluble fiber to hold water is what allows fruits and soft vegetable parts to contain water and yet maintain their firm shape.
Roots and tubers
Roots and tubers
Cow’s milk contains about one gram of calcium per liter, about four times as much as human breast milk. There is nothing special about the calcium in milk; it is just as easily absorbed as other forms of calcium from other sources. People eating a typical Western diet absorb only about 40% of the calcium they consume.
Cow’s milk contains about one gram of calcium per liter, about four times as much as human breast milk. There is nothing special about the calcium in milk; it is just as easily absorbed as other forms of calcium from other sources. People eating a typical Western diet absorb only about 40% of the calcium they consume.
There are hundreds of studies proclaiming the health benefits of eating whole grains, but the problem is that these studies compare diets rich in whole grains to diets rich in refined grains and sugars. These studies do show that whole grains are healthier for us than refined grains (flours), but they do not prove that whole grains are healthy. In order to prove that, you’d have to compare a diet that contains grains to a diet that contains no grains. Pretty much any whole food is healthier for us than refined carbohydrates, so proving that whole grains beat 
There are hundreds of studies proclaiming the health benefits of eating whole grains, but the problem is that these studies compare diets rich in whole grains to diets rich in refined grains and sugars. These studies do show that whole grains are healthier for us than refined grains (flours), but they do not prove that whole grains are healthy. In order to prove that, you’d have to compare a diet that contains grains to a diet that contains no grains. Pretty much any whole food is healthier for us than refined carbohydrates, so proving that whole grains beat 
