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Tag: glucose

  • The Validity of SIBO Tests  | NutritionFacts.org

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    Even if we could accurately diagnose small intestinal bacterial overgrowth (SIBO), if there is no difference in symptoms between those testing positive and those testing negative, what’s the point?

    Gastrointestinal symptoms like abdominal pain and bloating account for millions of doctor visits every year. One of the conditions that may be considered for such a “nonspecific presentation” of symptoms is SIBO, a concept that “has gained popularity on the internet in addition to certain clinical and research circles.” SIBO is “broadly defined as excessive bacteria in the small intestine” and typically treated with antibiotics, but “dispensing antibiotics to patients with the nonspecific, common symptoms associated with SIBO is not without risks,” such as the fostering of antibiotic resistance, the emergence of side effects, and the elimination of our good bacteria that could set us up for an invasion of bad bugs like C. diff—all for a condition that may not even be real.

    Even alternative medicine journals admit that SIBO is being overdiagnosed, creating “confusion and fear.” SIBO testing “is overused and overly relied upon. Diagnoses are often handed out quickly and without adequate substantiation. Patients can be indoctrinated into thinking SIBO is a chronic condition that can not be cleared and will require lifelong management. This is simply not true for most and is an example of the damage done by overzealousness.” “The ‘monster’ that we now perceive SIBO to be may be no more than a phantom.”

    The traditional method for a diagnosis was a small bowel aspiration, an invasive test where a long tube is snaked down the throat to take a sample and count the bugs down there, as you can see at 2:10 in my video Are Small Intestinal Bacterial Overgrowth (SIBO) Tests Valid?.

    This method has been almost entirely replaced with breath tests. Normally, a sugar called glucose is almost entirely absorbed in the small intestine, so it never makes it down to the colon. So, the presence of bacterial fermentation of that sugar suggests there are bacteria in the small intestine. Fermentation can be detected because the bacteria produce specific gases that get absorbed in our bloodstream before being exhaled from our lungs, which can then be detected with a breathalyzer-type machine.

    Previously, the sugar lactulose was used, but “lactulose breath tests do not reliably detect the overgrowth of bacteria,” so researchers switched to glucose. However, when glucose was finally put to the test, it didn’t work. The bacterial load in the small intestine was similar for those testing positive or negative, so that wasn’t a useful test either. It turns out that glucose can make it down to the colon after all.

    Researchers labeled the glucose dose with a tracer and found that nearly half of the positive results from glucose breath tests were false positives because individuals were just fermenting it down in their colon, where our bacteria are supposed to be. So, “patients who are incorrectly labeled with SIBO may be prescribed multiple courses of antibiotics” for a condition they don’t even have.

    Why do experts continue to recommend breath testing? Could it be because the “experts” were at a conference supported by a breath testing company, and most had personally received funds from SIBO testing or antibiotic companies?

    Even if we could properly diagnose SIBO, does it matter? For those with digestive symptoms, there is a massive range of positivity for SIBO from approximately 4 percent to 84 percent. Researchers “found there to be no difference in overall symptom scores between those testing positive against those testing negative for SIBO…” So, a positive test result could mean anything. Who cares if some people have bacteria growing in their small intestines if it doesn’t correlate with symptoms?

    Now, antibiotics can make people with irritable bowel-type symptoms who have been diagnosed with SIBO feel better. Does that prove SIBO was the cause? No, because antibiotics can make just as many people feel better who are negative for SIBO. Currently, the antibiotic rifaximin is most often used for SIBO, but it is “not currently FDA-approved for use in this indication, and its cost can be prohibitive.” (The FDA is the U.S. Food and Drug Administration.) In fact, no drug has been approved for SIBO in the United States or Europe, so even with good insurance, it may cost as much as $50 a day in out-of-pocket expenses, and the course is typically two weeks.

    What’s more, while antibiotics may help in the short term, they may make matters worse in the long term. Those “who are given a course of antibiotics are more than three times as likely to report more bowel symptoms 4 months later than controls.” So, what can we do for these kinds of symptoms? That’s exactly what I’m going to turn to next.

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    Michael Greger M.D. FACLM

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  • Feeding Hope: Diets To Starve Cancer in Dogs | Animal Wellness Magazine

    Feeding Hope: Diets To Starve Cancer in Dogs | Animal Wellness Magazine

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    When we hear the word “cancer,” our world stops. For dog parents, this diagnosis can feel like a death sentence. But what if the key to fighting this formidable foe was sitting right on your kitchen counter? Recent research suggests that specific diets might have the power to starve cancer cells in dogs, offering a glimmer of hope in what often feels like a hopeless battle.

    The Science of Starving Cancer

    Cancer cells are greedy. They consume glucose and glutamine at a much higher rate than normal cells. This unique metabolic profile has led scientists to explore diets that limit these nutrients, essentially attempting to “starve” the cancer. While it sounds simple, the science behind it is complex and fascinating, opening up new frontiers in canine cancer treatment.

    Ketogenic Diets: Fueling the Fight

    One approach gaining traction is the ketogenic diet. High in fat, moderate in protein, and very low in carbohydrates, this diet forces the body to burn fats rather than carbohydrates. While normal cells can adapt to using ketones for energy, cancer cells often cannot, potentially slowing their growth. But is trading your dog’s kibble for keto the answer?

    A Possible Tale of Triumph

    A vibrant Labrador, Bella, is diagnosed with an aggressive form of lymphoma. Her human, Jack, is devastated but determined. Under veterinary guidance, Jack transitions Bella to a carefully balanced ketogenic diet. Months later, her oncologist is astounded by her progress. While it’s not a cure-all, the diet has the potential to play a crucial role in Bella’s fight, giving her and Jack precious extra time together.

    Balancing Act or Risky Business?

    Not all veterinary professionals are sold on cancer-starving diets. Critics argue that drastically altering a dog’s diet could lead to nutritional imbalances, especially in a body already fighting cancer. The debate rages on, highlighting the need for more research and individualized approaches to canine cancer care.

    Exploring Other Cancer-Fighting Foods Beyond Keto

    While the ketogenic diet grabs headlines, other dietary approaches also show promise. Foods rich in Omega-3 fatty acids, certain vegetables, and even specific herbs have demonstrated anti-cancer properties in some studies. The key is finding a balance that supports overall health while potentially hindering cancer growth.

    Implementing Diets to Starve Cancer in Dogs is a Team Effort

    If you’re considering diets to starve cancer in dogs, remember: this is not a DIY project. Working closely with your veterinarian and a veterinary nutritionist is crucial. They can help tailor a diet that meets your dog’s specific needs, taking into account the type of cancer, overall health status, and potential drug interactions.

    The Emotional Journey: Hope on a Plate

    Changing your dog’s diet in the face of cancer can be emotionally charged. It’s a tangible way to feel like you’re fighting back against a relentless enemy. However, it’s important to manage expectations and focus on quality of life. Remember, food is more than just fuel – it’s comfort, it’s routine, it’s love.

    Conclusion: Nourishing Body and Soul

    The idea of starving cancer through diet offers a new weapon in the arsenal against this devastating disease. While not a magic bullet, these dietary approaches represent hope – hope that we can fight cancer not just with harsh treatments, but with the very food we offer our beloved companions. As research continues, we may find that the path to healing starts in the bowl. Until then, we feed our dogs with love, with hope, and with the unshakeable belief that every meal is an opportunity to nourish not just their bodies, but their fighting spirit.


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    Animal Wellness is North America’s top natural health and lifestyle magazine for dogs and cats, with a readership of over one million every year. AW features articles by some of the most renowned experts in the pet industry, with topics ranging from diet and health related issues, to articles on training, fitness and emotional well being.

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    Animal Wellness

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  • Irregular Meals, Night Shifts, and Metabolic Harms  | NutritionFacts.org

    Irregular Meals, Night Shifts, and Metabolic Harms  | NutritionFacts.org

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    What can shift workers do to moderate the adverse effects of circadian rhythm disruption?

    Shift workers may have higher rates of death from heart disease, stroke, diabetes, dementia, and cardiovascular disease, as well as higher rates of death from cancer. Graveyard shift, indeed! But, is it just because they’re eating out of vending machines or not getting enough sleep? Highly controlled studies have recently attempted to tease out these other factors by putting people on the same diets with the same sleep—but at the wrong time of day. Redistributing eating to the nighttime resulted in elevated cholesterol and increases in blood pressure and inflammation. No wonder shift workers are at higher risk. Shifting meals to the night in a simulated night-shift protocol effectively turned about one-third of the subjects prediabetic in just ten days. Our bodies just weren’t designed to handle food at night, as I discuss in my video The Metabolic Harms of Night Shifts and Irregular Meals.

    Just as avoiding bright light at night can prevent circadian misalignment, so can avoiding night eating. We may have no control over the lighting at our workplace, but we can try to minimize overnight food intake, which has been shown to help limit the negative metabolic consequences of shift work. When we finally do get home in the morning, though, we may disproportionately crave unhealthy foods. In one experiment, 81 percent of participants in a night-shift scenario chose high-fat foods, such as croissants, out of a breakfast buffet, compared to just 43 percent of the same subjects during a control period on a normal schedule.

    Shiftwork may also leave people too fatigued to exercise. But, even at the same physical activity levels, chronodisruption can affect energy expenditure. Researchers found that we burn 12 to 16 percent fewer calories while sleeping during the daytime compared to nighttime. Just a single improperly-timed snack can affect how much fat we burn every day. Study subjects eating a specified snack at 10:00 am burned about 6 more grams of fat from their body than on the days they ate the same snack at 11:00 pm. That’s only about a pat and a half of butter’s worth of fat, but it was the identical snack, just given at a different time. The late snack group also suffered about a 9 percent bump in their LDL cholesterol within just two weeks.

    Even just sleeping in on the weekends may mess up our metabolism. “Social jetlag is a measure of the discrepancy in sleep timing between our work days and free days.” From a circadian rhythm standpoint, if we go to bed late and sleep in on the weekends, it’s as if we flew a few time zones west on Friday evening, then flew back Monday morning. Travel-induced jet lag goes away in a few days, but what might the consequences be of constantly shifting our sleep schedule every week over our entire working career? Interventional studies have yet put it to the test, but population studies suggest that those who have at least an hour of social jet lag a week (which may describe more than two-thirds of people) have twice the odds of being overweight. 

    If sleep regularity is important, what about meal regularity? “The importance of eating regularly was highlighted early by Hippocrates (460–377 BC) and later by Florence Nightingale,” but it wasn’t put to the test until the 21st century. A few population studies had suggested that those eating meals irregularly were at a metabolic disadvantage, but the first interventional studies weren’t published until 2004. Subjects were randomized to eat their regular diets divided into six regular eating occasions a day or three to nine daily occasions in an irregular manner. Researchers found that an irregular eating pattern can cause a drop in insulin sensitivity and a rise in cholesterol levels, as well as reduce the calorie burn immediately after meals in both lean and obese individuals. The study participants ended up eating more, though, on the irregular meals, so it’s difficult to disentangle the circadian effects. The fact that overweight individuals may overeat on an irregular pattern may be telling in and of itself, but it would be nice to see such a study repeated using identical diets to see if irregularity itself has metabolic effects.

    Just such a study was published in 2016: During two periods, people were randomized to eat identical foods in a regular or irregular meal pattern. As you can see in the graph below and at 4:47 in my video, during the irregular period, people had impaired glucose tolerance, meaning higher blood sugar responses to the same food.

    They also had lower diet-induced thermogenesis, meaning the burning of fewer calories to process each meal, as seen in the graph below and at 4:55 in my video.

    The difference in thermogenesis only came out to be about ten calories per meal, though, and there was no difference in weight changes over the two-week periods. However, diet-induced thermogenesis can act as “a satiety signal.” The extra work put into processing a meal can help slake one’s appetite. And, indeed, “lower hunger and higher fullness ratings” during the regular meal period could potentially translate into better weight control over the long term. 

    The series on chronobiology is winding down with just two videos left in this series: Shedding Light on Shedding Weight and Friday Favorites: Why People Gain Weight in the Fall.

    If you missed any of the other videos, see the related posts below. 
     

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    Michael Greger M.D. FACLM

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  • Circadian Rhythms and Our Blood Sugar Levels  | NutritionFacts.org

    Circadian Rhythms and Our Blood Sugar Levels  | NutritionFacts.org

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    The same meal eaten at the wrong time of day can double blood sugar. 

    We’ve known for more than half a century that our glucose tolerance—the ability of our body to keep our blood sugars under control—declines as the day goes on. As you can see in the graph below and at 0:25 in my video How Circadian Rhythms Affect Blood Sugar Levels, if you hook yourself up to an IV and drip sugar water into your vein at a steady pace throughout the day, your blood sugars will start to go up at about 8:00 pm, even though you haven’t eaten anything and the infusion rate didn’t change.

    The same amount of sugar is going into your system every minute, but your ability to handle it deteriorates in the evening before bouncing right back in the morning. A meal eaten at 8:00 pm can cause twice the blood sugar response as an identical meal eaten at 8:00 am, as shown in the graph below and at 0:51 in my video. It’s as if you ate twice as much. Your body just isn’t expecting you to be eating when it’s dark outside. Our species may have only discovered how to use fire about a quarter million years ago. We just weren’t built for 24-hour diners. 

    One of the tests for diabetes is called the glucose tolerance test, which sees how fast our body can clear sugar from our bloodstream. You swig down a cup of water with about four and a half tablespoons of regular corn syrup mixed in, then have your blood sugar measured two hours later. By that point, your blood sugar should be under 140 mg/dL. Between 140 and 199 is considered to be a sign of prediabetes, and 200 and up is a sign of full-blown diabetes, as you can see in the graph below and at 1:37 in my video. 

    The circadian rhythm of glucose tolerance is so powerful that a person can test normal in the morning but as a prediabetic later in the day. Prediabetics who average 163 mg/dL at 7:00 am may test out as frank diabetics at over 200 mg/dL at 7:00 pm, as you can see in the graph below and at 1:53 in my video. 

    Choosing lower glycemic foods may help promote weight loss, but timing is critical. Due to this circadian pattern in glucose tolerance, a low-glycemic food at night can cause a higher blood sugar spike than a high-glycemic food eaten in the morning, as you can see below and at 2:05 in my video.

    We’re so metabolically crippled at night that researchers found that eating a bowl of All Bran cereal at 8:00 pm caused as high a blood sugar spike as eating Rice Krispies at 8:00 am, as you can see in the graph below and at 2:23 in my video.

    High glycemic foods at night would seem to represent the worst of both worlds. So, if you’re going to eat refined grains and sugary junk, it might be less detrimental in the morning, as you can see in the graph below and at 2:32 in my video.  

    The drop in glucose tolerance over the day could therefore help explain the weight-loss benefits of frontloading calories towards the beginning of the day. Even just taking lunch earlier versus later may make a difference, as you can see in the graph below and at 2:48 in my video.

    People randomized to eat a large lunch at 4:30 pm suffered a 46 percent greater blood sugar response compared to an identical meal eaten just a few hours earlier at 1:00 pm. A meal at 7:00 am can cause 37 percent lower blood sugars than an identical meal at 1:00 pm, as you can see below, and at 3:04 in my video.

    Now, there doesn’t seem to be any difference between a meal at 8:00 pm and the same meal at midnight; they both seem to be too late, as you can see below, and at 3:15 in my video.

    But, eating that late, at midnight or even 11:00 pm, can so disrupt your circadian rhythm that it can mess up your metabolism the next morning, resulting in significantly higher blood sugars after breakfast, compared to eating the same dinner at 6:00 pm the evening before, as shown in the graph below and at 3:32 in my video.

    So, these revelations of chronobiology bring the breakfast debate full circle. Skipping breakfast not only generally fails to cause weight loss, but it worsens overall daily blood sugar control in both diabetic individuals and people who are not diabetic, as you can see in the graph below and at 3:44 in my video.

    Below and at 3:53, you can see a graph showing how the breakfast skippers have higher blood sugars even while they’re sleeping 20 hours later. This may help explain why those who skip breakfast appear to be at higher risk of developing type 2 diabetes in the first place. 

    Breakfast skippers also tend to have higher rates of heart disease, as well as having higher rates of atherosclerosis, in general. Is this just because “skipping breakfast tends to cluster with other unhealthy choices, including smoking” and sicklier eating habits overall? The link between skipping breakfast and heart disease—even premature death in general—seems to survive attempts to control for these confounding factors, but you don’t really know until you put it to the test.

    Does skipping breakfast lead to higher cholesterol, for example? Yes, researchers found a significant rise in LDL (bad) cholesterol in study participants randomized to skip breakfast; they were about 10 points higher within just two weeks, as you can see below and at 4:45 in my video.

    The Israeli study with the caloric distribution of 700 calories for breakfast, 500 for lunch, and 200 for dinner that I’ve discussed previously found that the triglycerides of the king-prince-pauper group (those eating more at breakfast versus dinner) got significantly better—a 60-point drop—while those of the pauper-prince-king group got significantly worse (a 26-point rise). So, consuming more calories in the morning relative to the evening may actually have a triple benefit: more weight loss, better blood sugar control, and lower heart disease risk, as you can see below and at 5:18 in my video. 

    If you’re going to skip any meal, whether you’re practicing intermittent fasting or time-restricted feeding (where you try to fit all of your food intake into a certain time window each day), it may be safer and more effective to skip dinner rather than breakfast.

    I’m back with the next installment of the chronobiology series! I previously explored eating breakfast for weight loss (Is Breakfast the Most Important Meal for Weight Loss? and Is Skipping Breakfast Better for Weight Loss?), introduced chronobiology (How Circadian Rhythms Can Control Your Health and Weight), and looked at the science on eating more in the mornings than the evenings (Eat More Calories in the Morning to Lose Weight, Breakfast Like a King, Lunch Like a Prince, Dinner Like a Pauper, and Eat More Calories in the Morning Than the Evening).

    Next, you’ll see How to Sync Your Central Circadian Clock to Your Peripheral Clocks.

    The series will wrap up in the next couple of weeks. See videos and blogs in related posts below.

    Note: The Israeli 700/500/200 study that I mentioned is detailed in the Breakfast Like a King, Lunch Like a Prince, Dinner Like a Pauper video if you want to know more. Also, check the corresponding blog in related posts. 

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    Michael Greger M.D. FACLM

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  • Muscle Shrinkage and Bone Loss on Keto Diets?  | NutritionFacts.org

    Muscle Shrinkage and Bone Loss on Keto Diets?  | NutritionFacts.org

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    Ketogenic diets have been found to undermine exercise efforts and lead to muscle shrinkage and bone loss. 
     
    An official International Society of Sports Nutrition position paper covering keto diets notes the “ergolytic effect” of keto diets on both high- and low-intensity workouts. Ergolytic is the opposite of ergogenic. Ergogenic means performance-boosting, whereas ergolytic means performance-impairing. 
     
    For nonathletes, ketosis may also undermine exercise efforts. Ketosis was correlated with increased feelings of “perceived exercise effort” and “also significantly correlated to feelings of ‘fatigue’ and to ‘total mood disturbance,’” during physical activity. “Together, these data suggest that the ability and desire to maintain sustained exercise might be adversely impacted in individuals adhering to ketogenic diets for weight loss.” 
     
    You may recall that I’ve previously discussed that shrinkage of measured muscle mass among CrossFit trainees has been reported. So, a ketogenic diet may not just blunt the performance of endurance athletes, but their strength training as well. As I discuss in my video Keto Diets: Muscle Growth and Bone Density, study participants performed eight weeks of the battery of standard upper and lower body training protocols, like bench presses, pull-ups, squats, and deadlifts, and there was no surprise. You boost muscle mass—unless you’re on a keto diet, in which case there was no significant change in muscle mass after all that effort. Those randomized to a non-ketogenic diet added about three pounds of muscle mass, whereas the same amount of weight lifting on the keto diet tended to subtract muscle mass by about 3.5 ounces on average. How else could you do eight weeks of weight training and not gain a single ounce of muscle on a ketogenic diet? Even keto diet advocates call bodybuilding on a ketogenic diet an “oxymoron.” 
     
    What about bone loss? Sadly, bone fractures are one of the side effects that disproportionately plague children placed on ketogenic diets, along with slowed growth and kidney stones. Ketogenic diets may cause a steady rate of bone loss as measured in the spine, presumed to be because ketones are acidic, so keto diets can put people in what’s called a “chronic acidotic state.” 
     
    Some of the case reports of children on keto diets are truly heart-wrenching. One nine-year-old girl seemed to get it all, including osteoporosis, bone fractures, and kidney stones, then she got pancreatitis and died. Pancreatitis can be triggered by having too much fat in your blood. As you can see in the graph below and at 2:48 in my video, a single high-fat meal can cause a quintupling of the spike in triglycerides in your bloodstream within hours of consumption, which can put you at risk for inflammation of the pancreas.  

    The young girl had a rare genetic disorder called glucose transporter deficiency syndrome. She was born with a defect in ferrying blood sugar into her brain. That can result in daily seizures starting in infancy, but a ketogenic diet can be used as a way to sneak fuel into the brain, which makes a keto diet a godsend for the 1 in 90,000 families stricken with this disorder.

    As with anything in medicine, it’s all about risks versus benefits. As many as 30 percent of patients with epilepsy don’t respond to anti-seizure drugs. Unfortunately, the alternatives aren’t pretty and can include brain surgery that implants deep electrodes through the skull or even removes a lobe of your brain. This can obviously lead to serious side effects, but so can having seizures every day. If a ketogenic diet can help with seizures, the pros can far outweigh the cons. For those just choosing a diet to lose weight, though, the cost-benefit analysis would really seem to go the other way. Thankfully, you don’t need to mortgage your long-term health for short-term weight loss. We can get the best of both worlds by choosing a healthy diet, as I discussed in my video Flashback Friday: The Weight Loss Program That Got Better with Time.
     
    Remember the study that showed the weight loss was nearly identical in those who had been told to eat the low-carb Atkins diet for a year and those told to eat the low-fat Ornish diet, as seen below and at 4:18 in my video? The authors concluded, “This supports the practice of recommending any diet that a patient will adhere to in order to lose weight.” That seems like terrible advice. 

    There are regimens out there like “The Last Chance Diet which consisted of a low-calorie liquid formula made from leftover byproducts from a slaughterhouse [that] was linked to approximately 60 deaths from cardiovascular-related events.” An ensuing failed lawsuit from one widower laid the precedent for the First Amendment protection for those who produce deadly diet books. 

    It’s possible to construct a healthy low-carb diet or an unhealthy low-fat one—a diet of cotton candy would be zero fat—but the health effects of a typical low-carb ketogenic diet like Atkins are vastly different from a low-fat plant-based diet like Ornish’s. As you can see in the graph below and at 5:26 in my video, they would have diametrically opposed effects on cardiovascular risk factors in theory, based on the fiber, saturated fat, and cholesterol contents of their representative meal plans. 

    And when actually put to the test, low-carb diets were found to impair artery function. Over time, blood flow to the heart muscle itself is improved on an Ornish-style diet and diminished on a low-carb one, as shown below and at 5:44 in my video. Heart disease tends to progress on typical weight-loss diets and actively worsens on low-carb diets, but it may be reversed by an Ornish-style diet. Given that heart disease is the number one killer of men and women, “recommending any diet that a patient will adhere to in order to lose weight” seems irresponsible. Why not tell people to smoke? Cigarettes can cause weight loss, too, as can tuberculosis and a meth habit. The goal of weight loss is not to lighten the load for your pallbearers. 

     
    For more on keto diets, see my videos on the topic. Interested in enhancing athletic performance? Check out the related videos below. 

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    Michael Greger M.D. FACLM

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  • Keto Diet to Effectively Fight Cancer?  | NutritionFacts.org

    Keto Diet to Effectively Fight Cancer?  | NutritionFacts.org

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    What does the science say about the clinical use of ketogenic diets for epilepsy and cancer? 

    Blood sugar, also known as blood glucose, is the universal go-to fuel for the cells throughout our bodies. Our brain burns through a quarter pound of sugar a day because “glucose is the preferred metabolic fuel.” We can break down proteins and make glucose from scratch, but most comes from our diet in the form of sugars and starches. If we stop eating carbohydrates (or stop eating altogether), most of our cells switch over to burning fat. Fat has difficulty getting through the blood-brain barrier, though, and our brain has a constant, massive need for fuel. Just that one organ accounts for up to half of our energy needs. Without it, the lights go out…permanently. 

    To make that much sugar from scratch, our body would need to break down about half a pound of protein a day. That means we’d cannibalize ourselves to death within two weeks, but people can fast for months. What’s going on? The answer to the puzzle was discovered in 1967. Harvard researchers famously stuck catheters into the brains of obese subjects who had been fasting for more than a month and discovered that ketones had replaced glucose as the preferred fuel for the brain. Our liver can turn fat into ketones, which can then breach the blood-brain barrier and sustain our brain if we aren’t getting enough carbohydrates. Switching fuels has such an effect on brain activity that it has been used to treat epilepsy since antiquity. 

    In fact, the prescription of fasting for the treatment of epileptic seizures dates back to Hippocrates. In the Bible, even Jesus seems to have concurred. To this day, it’s unclear why switching from blood sugar to ketones as a primary fuel source has such a dampening effect on brain overactivity. How long can one fast? To prolong the fasting therapy, in 1921, a distinguished physician scientist at the Mayo Clinic suggested trying what he called “ketogenic diets,” high-fat diets designed to be so deficient in carbohydrates that they could effectively mimic the fasting state. “Remarkable improvement” was noted the first time it was put to the test, efficacy that was later confirmed in randomized, controlled trials. Ketogenic diets started to fall out of favor in 1938 with the discovery of the anti-seizure drug that would become known as Dilantin, but they’re still being used today as a third- or fourth-line treatment for drug-refractory epilepsy in children. 

    Oddly, the success of ketogenic diets against pediatric epilepsy seems to get conflated by “keto diet” proponents into suggesting a ketogenic diet is beneficial for everyone. Know what else sometimes works for intractable epilepsy? Brain surgery, but I don’t hear people clamoring to get their skulls sawed open. Since when do medical therapies translate into healthy lifestyle choices? Scrambling brain activity with electroshock therapy can be helpful in some cases of major depression, so should we get out the electrodes? Ketogenic diets are also being tested to see if they can slow the growth of certain brain tumors. Even if they work, you know what else can help slow cancer growth? Chemotherapy. So why go keto when you can just go chemo? 

    Promoters of ketogenic diets for cancer are paid by so-called ketone technology companies that offer to send you salted caramel bone broth powder for a hundred bucks a pound or companies that market ketogenic meals and report “extraordinary” anecdotal responses in some cancer patients. But more concrete evidence is simply lacking, and even the theoretical underpinnings may be questionable. A common refrain is that “cancer feeds on sugar.” But all cells feed on sugar. Advocating ketogenic diets for cancer is like saying Hitler breathed air so we should boycott oxygen. 

    Cancer can feed on ketones, too. Ketones have been found to fuel human breast cancer growth and drive metastases in an experimental model, more than doubling tumor growth. Some have even speculated that this may be why breast cancer often metastasizes to the liver, the main site of ketone production. As you can see below and at 4:59 in my video Is Keto an Effective Cancer-Fighting Diet?, if you drip ketones directly onto breast cancer cells in a petri dish, the genes that get turned on and off make for much more aggressive cancer, associated with significantly lower five-year survival in breast cancer patients, as you can see in the following graph and at 5:05 in my video. Researchers are even considering designing ketone-blocking drugs to prevent further cancer growth by halting ketone production.  

    Let’s also think about what eating a ketogenic diet might entail. High animal fat intake may increase the mortality risk among breast cancer survivors and potentially play a role in the development of breast cancer in the first place through oxidative stress, hormone disruption, or inflammation. This applies to men, too. “A strong association” has been found “between saturated fat intake and prostate cancer progression and survival.” Those in the top third of consumption of these kinds of fat-rich animal foods appeared to triple their risk of dying from prostate cancer. This isn’t necessarily fat in general either. No difference has been found in breast cancer death rates based on total fat intake. However saturated fat intake specifically may negatively impact breast cancer survival, increasing the risk of dying from it by 50 percent. There’s a reason the official American Cancer Society and American Society of Clinical Oncology Breast Cancer Survivorship Care Guideline recommend a dietary pattern for breast cancer patients that’s essentially the opposite of a ketogenic diet. It calls for a diet that’s “high in vegetables, fruits, whole grains, and legumes [beans, split peas, chickpeas, and lentils]; low in saturated fats; and limited in alcohol consumption.” 

    “To date, not a single clinical study has shown a measurable benefit from a ketogenic diet in any human cancer.” There are currently at least a dozen trials underway, however, and the hope is that at least some cancer types will respond. Still, even then, that wouldn’t serve as a basis for recommending ketogenic diets for the general population any more than recommending everyone get radiation, surgery, and chemo just for kicks. 

    “Keto” has been the most-searched keyword on NutritionFacts.org for months, and I didn’t have much specific to offer…until now. Check out my other videos on the topic in related videos below. 

     For an overview of my cancer work, watch How Not to Die from Cancer. 

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    Michael Greger M.D. FACLM

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