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Tag: vegetarians

  • The Largest Study on Fasting in the World  | NutritionFacts.org

    The Largest Study on Fasting in the World  | NutritionFacts.org

    The Buchinger-modified fasting program is put to the test.

    A century ago, fasting—“starvation, as a therapeutic measure”—was described as “the ideal measure for the human hog…” (Fat shaming is not a new invention in the medical literature.) I’ve covered fasting for weight loss extensively in a nine-video series, but what about all the other purported benefits? I also have a video series on fasting for hypertension, but what about psoriasis, eczema, type 2 diabetes, lupus, metabolic disorder, rheumatoid arthritis, other autoimmune disorders, depression, and anxiety? Why hasn’t it been tested more?

    One difficulty with fasting research is: What do you mean by fasting? When I think of fasting, I think of water-only fasting, but, in Europe, they tend to practice “modified therapeutic fasting,” also known as Buchinger fasting, which is more like a very low-calorie juice fasting with some vegetable broth. Some forms of fasting may not even cut calories at all. As you can see below and at 1:09 in my video The World’s Largest Fasting Study, Ramadan fasting, for example, is when devout Muslims abstain from food and drink from sunrise to sunset, yet, interestingly, they end up eating the same amount—or even more food—overall.

    The largest study on fasting to date was published in 2019. More than a thousand individuals were put through a modified fast, cutting daily intake down to about ten cups of water, a cup of fruit juice, and a cup of vegetable soup. They reported very few side effects. In contrast, the latest water-only fasting data from a study that involved half as many people reported nearly 6,000 adverse effects. Now, the modified fasting study did seem to try to undercount adverse effects by only counting reported symptoms if they were repeated three times. However, adverse effects like nausea, feeling faint, upset stomach, vomiting, or palpitations were “observed only in single cases,” whereas the water-only fasting study reported about 100 to 200 of each, as you can see below and at 2:05 in my video. What about the benefits though?

    In the modified fasting study, participants self-reported improvements in physical and emotional well-being, along with a surprising lack of hunger. What’s more, the vast majority of those who came in with a pre-existing health complaint reported feeling better, with less than 10 percent stating that their condition worsened, as you can see in the graph below and at 2:24 in my video

    However, the study participants didn’t just fast; they also engaged in a lifestyle program, which included being on a plant-based diet before and after the modified fast. If only the researchers had had some study participants follow the healthier, plant-based diet without the fast to tease out fasting’s effects. Oh, but they did! About a thousand individuals fasted for a week on the same juice and vegetable soup regimen and others followed a normocaloric (normal calorie) vegetarian diet.

    As you can see below and at 2:54 in my video, both groups experienced significant increases in both physical and mental quality of life, and, interestingly, there was no significant difference between the groups.

    In terms of their major health complaints—including rheumatoid arthritis; chronic pain syndromes, like osteoarthritis, fibromyalgia, and back pain; inflammatory and irritable bowel disease; chronic pulmonary diseases; and migraine and chronic tension-type headaches—the fasting group appeared to have an edge, but both groups did well, with about 80 percent reporting improvements in their condition and only about 4 percent reporting feeling worse, as you can see below and at 3:25 in my video

    Now, this was not a randomized study; people chose which treatment they wanted to follow. So, maybe, for example, those choosing fasting were sicker or something. Also, the improvements in quality of life and disease status were all subjective self-reporting, which is ripe for placebo effects. There was no do-nothing control group, and the response rates to the follow-up quality of life surveys were only about 60 to 70 percent, which also could have biased the results. But extended benefits are certainly possible, given they all tended to improve their diets, as you can see below and at 4:00 in my video.

    They ate more fruits and vegetables, and less meats and sweets, and therein may lie the secret. “Principally, the experience of fasting may support motivation for lifestyle change. Most fasters experience clarity of mind and feel a ‘letting go’ of past actions and experiences and thus may develop a more positive attitude toward the future.”

    As a consensus panel of fasting experts concluded, “Nutritional therapy (theory and practice) is a vital and integral component of fasting. After the fasting therapy and refeeding period, nutrition should follow the recommendations/concepts of a…plant-based whole-food diet…”

    If you missed the previous video, check out The Benefits of Fasting for Healing.

    Michael Greger M.D. FACLM

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  • What’s the Best Weight-Loss and Disease-Prevention Diet?  | NutritionFacts.org

    What’s the Best Weight-Loss and Disease-Prevention Diet?  | NutritionFacts.org

    The most effective diet for weight loss may also be the most healthful.

    Why are vegetarian diets so effective in preventing and treating diabetes? Maybe it is because of the weight loss. As I discuss in my video The Best Diet for Weight Loss and Disease Prevention, those eating more plant-based tend to be significantly slimmer. That isn’t based on looking at a cross-section of the population either. You can perform an interventional trial and put it to the test in a randomized, controlled community-based trial of a whole food, plant-based diet.

    “The key difference between this trial [of plant-based nutrition] and other approaches to weight loss was that participants were informed to eat the WFPB [whole food, plant-based] diet ad libitum and to focus efforts on diet, rather than increasing exercise.” Ad libitum means they could eat as much as they want; there was no calorie counting or portion control. They just ate. It was about improving the quality of the food rather than restricting the quantity of food. In the study, the researchers had participants focus just on a diet rather than exercising more exercise because they wanted to isolate the effects of eating more healthfully.

    So, what happened? At the start of the study, the participants were, on average, obese at nearly 210 pounds (95 kg) with an average height of about 5’5” (165 cm). Three months into the trial, they were down about 18 pounds (8 kg)—without portion restrictions and eating all the healthy foods they wanted. At six months in, they were closer to 26 pounds (12 kg) lighter. You know how these weight-loss trials usually go, though. However, this wasn’t an institutional study where the participants were locked up and fed. In this trial, no meals were provided. The researchers just informed them about the benefits of plant-based eating and encouraged them to eat that way on their own, with their own families, and in their own homes, in their own communities. What you typically see in these “free-living” studies is weight loss at six months, with the weight creeping back or even getting worse by the end of a year. But, in this study, the participants were able to maintain that weight loss all year, as you can see below and at 1:57 in my video.

    What’s more, their cholesterol got better, too, but the claim to fame is that they “achieved greater weight loss at 6 and 12 months than any other trial that does not limit energy [caloric] intake or mandate regular exercise.” That’s worth repeating. A whole food, plant-based diet achieved the greatest weight loss ever recorded at 6 and 12 months compared to any other such intervention published in the medical literature. Now, obviously, with very low-calorie starvation diets, you can drop down to any weight. “However, medically supervised liquid ‘meal replacements’ are not intended for ongoing use”—obviously, they’re just short-term fixes—“and are associated with ‘high costs, high attrition rates, and a high probability of regaining 50% or more of lost weight in 1 to 2 years.’” In contrast, the whole point of whole food, plant-based nutrition is to maximize long-term health and longevity.

    What about low-carb diets? “Studies on the effects of low-carbohydrate diets have shown higher rates of all-cause mortality”—meaning a shorter lifespan—“decreased peripheral flow-mediated dilation [artery function], worsening of coronary artery disease, and increased rates of constipation, headache, halitosis [bad breath], muscle cramps, general weakness, and rash.”

    The point of weight loss is not to fit into a smaller casket. A whole food, plant-based diet is more effective than low-carb diets for weight loss and has the bonus of having all good side effects, such as decreasing the risk of diabetes beyond just weight loss.

    “The lower risk of type 2 diabetes among vegetarians may be explained in part by improved weight status (i.e., lower BMI). However, the lower risk also may be explained by higher amounts of ingested dietary fiber and plant protein, the absence of meat- and egg-derived protein and heme iron, and a lower intake of saturated fat. Most studies report the lowest risk of type 2 diabetes among individuals who adhere to vegan diets. This may be explained by the fact that vegans, in contrast to ovo- and lacto-ovo-vegetarians, do not ingest eggs. Two separate meta-analyses linked egg consumption with a higher risk of type 2 diabetes.”

    Maybe it’s eating lower on the food chain, thereby avoiding the highest levels of persistent organic pollutants, like dioxins, PCBs, and DDT in animal products. Those have been implicated as a diabetes risk factor. Or maybe it has to do with the gut microbiome. With all that fiber in a plant-based diet, it’s no surprise there would be fewer disease-causing bugs and more protective gut flora, which can lead to less inflammation throughout the body that “may be the key feature linking the vegan gut microbiota with protective health effects”—including the metabolic dysfunction you can see in type 2 diabetes.

    The multiplicity of benefits from eating plant-based can help with compliance and family buy-in. “Whereas a household that includes people who do not have diabetes may be unlikely to enthusiastically follow a ‘diabetic diet,’ a low-fat plant-based approach is not disease-specific and has been shown to improve other chronic conditions. While the patient [with diabetes] will likely see improvement in A1C [blood sugar control], a spouse suffering from constipation or high blood pressure may also see improvements, as may children with weight issues,” if you make healthy eating a family affair.

    This is just a taste of my New York Times best-selling book, How Not to Diet. (As with all of my books, all proceeds I received went to charity.) Watch the book trailer. You may also be interested in its companion, The How Not to Diet Cookbook.

    Check out my hour-long Evidence-Based Weight Loss lecture for more. 

    Michael Greger M.D. FACLM

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  • Is Creatine Safe and Efficient for High Homocysteine?  | NutritionFacts.org

    Is Creatine Safe and Efficient for High Homocysteine?  | NutritionFacts.org

    Those on a healthy plant-based diet who have elevated homocysteine levels despite taking sufficient vitamin B12 may want to consider taking a gram a day of contaminant-free creatine.

    The average blood levels of homocysteine in men are about 1.5 points higher than in women, which may be one of the reasons men tend to be at higher risk for cardiovascular disease. Women don’t need to make as much creatine as men since they tend to have less muscle mass. That may help explain “the ‘gender gap’ in homocysteine levels.” If you remember from my previous video and as seen below and at 0:36 in The Efficacy and Safety of Creatine for High Homocysteine, in the process of making creatine, our body produces homocysteine as a by-product. So, for people with stubbornly high homocysteine levels that don’t respond sufficiently to B vitamins, “creatine supplementation may represent a practical strategy for decreasing plasma homocysteine levels”—that is, lowering the level of homocysteine into the normal range. 

    It seemed to work in rats. What about humans? Well, it worked in one study, but it didn’t seem to work in another. It didn’t work in yet another either. And, in another study, homocysteine levels were even driven up. So, this suggestion that taking creatine supplements would lower homocysteine was called into question. 

    However, all those studies were done with non-vegetarians, so they were already effectively supplementing with creatine every day in the form of muscle meat. In that way, researchers were testing higher versus lower supplementation. Those eating strictly plant-based make all their creatine from scratch, so they may be more sensitive to an added creatine source. There weren’t any studies on creatine supplementation in vegans to lower homocysteine until now. 

    Researchers took vegans who were not supplementing their diets with vitamin B12, so some of their homocysteine levels were through the roof. A few were as high as 50 when the ideal is more like under 10, for example. After taking some creatine for a few weeks, all of their homocysteine levels normalized. You can see the before and after in the graph below and at 2:04 in my video

    Now, they didn’t normalize, as that would have been a level under 10, but that’s presumably because they weren’t taking any B12. Give vegetarians and vegans vitamin B12 supplements, either dosing daily or once a week, and their levels normalize in a matter of months, as you can see below and at 2:20 in my video. However, the fact that you could bring down homocysteine levels with creatine alone, even without any B12, suggests—to me at least—that if your homocysteine is elevated (above 10) on a plant-based diet despite taking B12 supplements and eating greens and beans to get enough folate, it might be worth experimenting with supplementing with a gram of creatine a day for a few weeks to see if your homocysteine comes down. 

    Why just a single gram? That’s approximately how much non-vegetarians do not have to make themselves; it’s the amount that erased vegetarian discrepancies in blood and muscle, as you can see in the graph below and at 3:01 in my video, and how much has been shown to be safe in the longer term. 

    How safe is it? We can take a bit of comfort in the fact that it’s “one of the world’s best-selling dietary supplements,” with literally billions of servings taken, and the only consistently reported side effect has been weight gain, presumed to be from water retention. The only serious side effects appear to be among those with pre-existing kidney diseases taking whopping doses closer to 20 grams a day. A concern was raised that creatine could potentially form a carcinogen known as N-nitrososarcosine when it hit the acid bath of the stomach, but, when it actually put to the test, researchers found this does not appear to be a problem. 

    Bottom line: Doses of supplemental creatine up to 3 grams a day are “unlikely to pose any risk,” provided “high purity creatine” is used. However, as we all know, dietary supplements in the United States “are not regulated by the US Food and Drug Administration and may contain contaminants or variable quantities of the desired supplement” and may not even contain what’s on the label. We’re talking about “contaminants…that may be generated during the industrial production.” When researchers looked at 33 samples of creatine supplements made in the United States and Europe, they found that they all actually contained creatine, which is nice, but about half exceeded the maximum level recommended by food safety authorities for at least one contaminant. The researchers recommend that “consumers give their preference to products obtained by producers that ensure the highest quality control and certify the maximum amount of contaminants present in their products.” Easier said than done.

    Because of the potential risks, I don’t think people should take creatine supplements willy-nilly, but the potential benefits may exceed the potential risks if, again, you’re on a healthy plant-based diet and taking B12, and your homocysteine levels are still not under 10. In that case, I would suggest giving a gram a day of creatine a trying to see if it brings it down.

    The reason I did this whole video series goes back to “Risks of Ischaemic Heart Disease and Stroke in Meat Eaters, Fish Eaters, and Vegetarians Over 18 Years of Follow-Up: Results from the Prospective EPIC-Oxford Study,” which found that, although the overall cardiovascular risk is lower in vegetarians and vegans combined, they appeared to be at slightly higher stroke risk, as you can see in the graph below and at 5:06 in my video

    I went through a list of potential causes, as you can see at 5:11 and below, and arrived at elevated homocysteine. What’s the solution? A regular, reliable source of vitamin B12. The cheapest, easiest method that I personally use is one 2,500 mcg chewable tablet of cyanocobalamin, the most stable source of B12, once a week. (In fact, you can just use 2,000 mcg once a week.) And, again, a backup plan for those doing that but still having elevated homocysteine is an empirical trial of a single gram a day of creatine supplementation, which was shown to improve at least capillary blood flow in those who started out with high homocysteine levels. 

    In sum, plant-based diets appear to “markedly reduce risk” for multiple leading killer diseases—heart disease, type 2 diabetes, and many common types of cancer—but “an increased risk for stroke may represent an ‘Achilles heel.’ Nonetheless, vegans have the potential to achieve a truly exceptional ‘healthspan’ if they face this problem forthrightly by restricting salt intake and taking other practical measures that promote cerebrovascular [brain artery] health…Nonetheless, these considerations do not justify nutritional nihilism. On balance, low-fat vegan diets offer such versatile protection for long-term health that they remain highly recommendable. Most likely, the optimal strategy is to adopt such a [plant-based] diet, along with additional measures—appropriate food choices, exercising training, judicious supplementation [of vitamin B12]—that will mitigate the associated stroke risk.” And try not to huff whipped cream charging canister gas. Leave the “whippets” alone.

    This concludes my series on stroke risk. If you missed any of the other videos, see the related posts below.

    I’m assuming that nearly everyone taking their B12 will have normal homocysteine levels, so these last two videos are just for the rare person who doesn’t. However, those on a healthy plant-based diet with elevated homocysteine levels despite taking sufficient vitamin B12 should consider taking a gram a day of contaminant-free creatine, which should be about a quarter teaspoon.

    Where do you get contaminant-free creatine? Since regulations are so lax, you can’t rely on supplement manufacturers no matter what they say, so I would recommend going directly to the chemical suppliers that sell it to laboratories and guarantee a certain purity. Here are some examples (in alphabetical order) of some of the largest companies where you can get unadulterated creatine: Alfa Aesar, Fisher Scientific, Sigma-Aldrich, and TCI America.

    Michael Greger M.D. FACLM

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  • Creatinine to Normalize Homocysteine in Vegetarians?  | NutritionFacts.org

    Creatinine to Normalize Homocysteine in Vegetarians?  | NutritionFacts.org

    What are the consequences of having to make your creatine rather than relying on dietary sources?

    “Almost universally, research findings show a poor vitamin B12 status among vegetarians” because they aren’t taking vitamin B12 supplements like they should, which results in an elevation in homocysteine levels. This may explain why vegetarians were recently found to have higher rates of stroke, as you can see in the graph below and at 0:30 in my video Should Vegetarians Take Creatine to Normalize Homocysteine?.

    Of course, plant-based eating is just one of many ways to become deficient in vitamin B12. Even nitrous oxide (laughing gas) can do it in as little as two days, thanks to the recreational use of whipped cream canister gas. (I just learned about “whippits”!)

    When researchers gave vegetarians and vegans as little as 50 daily micrograms of cyanocobalamin, which is the recommended and most stable form of vitamin B12 supplement, their homocysteine levels, which had started up in the elevated zone, normalized right down into the safe zone under 10 mmol/L within only one to two months. Just 2,000 micrograms of cyanocobalamin once a week gave the same beautiful result, as you can see in the graph below and at 1:15 in my video

    Not always, though. In another study, even 500 daily micrograms, taken as either a sublingual chewable or swallowable regular B12 supplement, didn’t normalize homocysteine within a month, as shown below and at 1:24. Now, presumably, if the participants had kept it up, their levels would have continued to fall as they did in the 50-daily-microgram study.

    If you’re plant-based and have been taking your B12, but your homocysteine level is still too high (above 10 mmol/L), is there anything else you can do? Well, inadequate folate intake can also increase homocysteine, but folate comes from the same root as foliage. It’s found in beans and leaves, concentrated in greens. If you’re eating beans and greens, taking your B12, and your homocysteine level is still too high, I’d suggest taking 1 gram of creatine a day as an experiment, then getting your homocysteine levels retested in a month to see if it helped.

    Creatine is a compound formed naturally in the human body that is primarily involved with energy production in our muscles and brain. It’s also formed naturally in the bodies of many other animals. So, when we eat their muscles, we can also take in some of the creatine in their bodies through our diet. We only need about 2 grams of creatine a day, so those who eat meat may get about 1 gram from their diet and their body makes the rest from scratch. There are rare birth defects where you’re born without the ability to make it, in which case, you have to get it from your diet. Otherwise, our bodies can make as much as we need to maintain normal concentrations in our muscles.

    As you can see in the graph below and at 2:54 in my video, when you cut out meat, the amount of creatine floating around in your bloodstream goes down.

    However, the amount in your brain remains the same, as shown in the graph below and at 2:57. This shows that dietary creatinine doesn’t influence the levels of brain creatine, because our brain makes all the creatine we need. The level in vegetarian muscles is lower, but that doesn’t seem to affect exercise performance, as both vegetarians and meat eaters respond to creatine supplementation with similar increases in muscle power output. If vegetarian muscle creatine were insufficient, then presumably an even bigger boost would be seen. So, all that seems to happen when we eat meat is that our body doesn’t have to make as much. What does all of this have to do with homocysteine?

    As you can see below and at 3:36 in my video, in the process of making creatine, our body produces homocysteine as a waste product. Now, normally this isn’t a problem because our body has two ways to detoxify it: by using vitamin B6 or a combination of vitamin B12 and folate. Vitamin B6 is found in both plant and animal foods, and it’s rare to be deficient. But, vitamin B12 is mainly found in animal foods, so its level can be too low in those eating plant-based who don’t also supplement or eat B12-fortified foods. And, as I mentioned, folate is concentrated in plant foods, so it can be low in those who don’t regularly eat greens, beans, or folic-acid-fortified grains. Without that escape valve, homocysteine levels can get too high. However, if you’re eating a healthy plant-based diet and taking your B12 supplement, your homocysteine levels should be fine. 

    What if they aren’t? We might predict that if we started taking creatine supplements, our level of homocysteine might go down since we won’t have to make so much of it from scratch, producing homocysteine as a by-product, but you don’t know until you put it to the test. I’ll cover that next. 

    This is the eleventh in a 12-video series exploring stroke risk. If you missed the last two, see Vegetarians and Stroke Risk Factors: Vitamin B12 and Homocysteine? and How to Test for Functional Vitamin B12 Deficiency.

    This whole creatine angle was new to me. I had long worried about homocysteine levels being too high among those getting inadequate B12 intake, but I didn’t realize there was another potential mechanism for bringing it down other than with vitamin B. Let’s see if it pans out in my final video of the series: The Efficacy and Safety of Creatine for High Homocysteine

    Michael Greger M.D. FACLM

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  • Testing for Vitamin B12 Deficiency  | NutritionFacts.org

    Testing for Vitamin B12 Deficiency  | NutritionFacts.org

    Many doctors mistakenly rely on serum B12 levels in the blood to test for vitamin B12 deficiency.

    There were two cases of young, strictly vegetarian individuals with no known vascular risk factors. One suffered a stroke, and the other had multiple strokes. Why? Most probably because they weren’t taking vitamin B12 supplements, which leads to high homocysteine levels, which can attack our arteries.

    So, those eating plant-based who fail to supplement with B12 may increase their risk of both heart disease and stroke. However, as you can see in the graph below and at 0:47 in my video How to Test for Functional Vitamin B12 Deficiency, vegetarians have so many heart disease risk factor benefits that they are still at lower risk overall, but this may help explain why vegetarians were found to have more stroke. This disparity would presumably disappear with adequate B12 supplementation, and the benefit of lower heart disease risk would grow even larger.

    Compared with non-vegetarians, vegetarians enjoy myriad other advantages, such as better cholesterol, blood pressure, blood sugars, and obesity rates. But, what about that stroke study? Even among studies that have shown benefits, “the effect was not as pronounced as expected, which may be a result of poor vitamin B12 status due to a vegetarian diet. Vitamin B12 deficiency may negate the cardiovascular disease prevention benefits of vegetarian diets. To further reduce the risk of cardiovascular disease, vegetarians should be advised to use vitamin B12 supplements.” 

    How can you determine your B12 status? By the time you’re symptomatic with B12 deficiency, it’s too late. And, initially, the symptoms can be so subtle that you might even miss them. What’s more, you develop metabolic vitamin B12 deficiency well before you develop a clinical deficiency, so there’s “a missed opportunity to prevent dementia and stroke” when you have enough B12 to avoid deficiency symptoms, but not enough to keep your homocysteine in check. “Underdiagnosis of this condition results largely from a failure to understand that a normal serum [blood level] B12 may not reflect an adequate functional B12 status.” The levels of B12 in our blood do not always represent the levels of B12 in our cells. We can have severe functional deficiency of B12 even though our blood levels are normal or even high.

    “Most physicians tend to assume that if the serum B12 is ‘normal,’ there is no problem,” but, within the lower range of normal, 30 percent of patients could have metabolic B12 deficiency, with high homocysteine levels. 

    Directly measuring levels of methylmalonic acid (MMA) or homocysteine is a “more accurate reflection of vitamin B12 functional statuses.” Methylmalonic acid can be checked with a simple urine test; you’re looking for less than a value of 4 micrograms per milligram of creatinine. “Elevated MMA is a specific marker of vitamin B12 deficiency while Hcy [homocysteine] rises in both vitamin B12 and folate deficiencies.” So, “metabolic B12 deficiency is strictly defined by elevation of MMA levels or by elevation of Hcy in folate-replete individuals,” that is, in those getting enough folate. Even without eating beans and greens, which are packed with folate, folic acid is added to the flour supply by law, so, these days, high homocysteine levels may be mostly a B12 problem. Ideally, you’re looking for a homocysteine level in your blood down in the single digits.

    Measured this way, “the prevalence of subclinical functional vitamin B12 deficiency is dramatically higher than previously assumed…” We’re talking about 10 to 40 percent of the general population, more than 40 percent of vegetarians, and the majority of vegans who aren’t scrupulous about getting their B12. Some suggest that those on plant-based diets should check their vitamin B12 status every year, but you shouldn’t need to if you’re adequately supplementing. 

    There are rare cases of vitamin B12 deficiency that can’t be picked up on any test, so it’s better to just make sure you’re getting enough.

    If you do get your homocysteine tested and it’s still too high, up in the double digits despite B12 supplementation and eating beans and greens, I have a suggestion for you in the final videos of this series, which we’ll turn to next with: Should Vegetarians Take Creatine to Normalize Homocysteine? and The Efficacy and Safety of Creatine for High Homocysteine.

    How did we end up here? To watch the full series if you haven’t yet, check the related posts below. 

    Michael Greger M.D. FACLM

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  • What About Homocysteine, Vitamin B12, and Vegetarians’ Stroke Risk?  | NutritionFacts.org

    What About Homocysteine, Vitamin B12, and Vegetarians’ Stroke Risk?  | NutritionFacts.org

    Not taking vitamin B12 supplements or regularly eating B12-fortified foods may explain the higher stroke risk found among vegetarians.

    Leonardo da Vinci had a stroke. Might his vegetarian diet have been to blame? “His stroke…may have been related to an increase in homocysteine level because of the long duration of his vegetarian diet.” A suboptimal intake of vitamin B12 is common in those eating plant-based diets (unless they take B12 supplements or regularly eat B12-fortified foods) and can lead to an increased level of homocysteine in the blood, which “is accepted as an important risk factor for stroke.”

    “Accepted” may be overstating it as there is still “a great controversy” surrounding the connection between homocysteine and stroke risk. But, as you can see in the graph below and at 0:57 in my video Vegetarians and Stroke Risk Factors: Vitamin B12 and Homocysteine?, those with higher homocysteine levels do seem to have more atherosclerosis in the carotid arteries that lead up to the brain, compared to those with single-digit homocysteine levels, and they also seem to be at higher risk for clotting ischemic strokes in observational studies and, more recently, bleeding hemorrhagic strokes, as well as increased risk of dying from cardiovascular disease and all causes put together. 

    Even more convincing are the genetic data. About 10 percent of the population has a gene that increases homocysteine levels by about 2 points, and they appear to have significantly higher odds of having a stroke. Most convincing would be randomized, double-blind, placebo-controlled trials to prove that lowering homocysteine with B vitamins can lower strokes, and, indeed, that appears to be the case for clotting strokes: Strokes with homocysteine-lowering interventions were more than five times as likely to reduce stroke compared with placebo.

    Ironically, one of the arguments against the role of homocysteine in strokes is that, “assuming that vegetarians have lower vitamin B12 concentrations than meat-eaters and that low vitamin B12 concentrations cause ischaemic stroke, then the incidence of stroke should be increased among vegetarians…but this is not the case.” However, it has never been studied until now.

    As you can see in the graph below and at 2:16 in my video, the EPIC-Oxford study researchers found that vegetarians do appear to be at higher risk.

    And no wonder, as about a quarter of the vegetarians and nearly three-quarters of the vegans studied were vitamin B12-depleted or B12-deficient, as you can see below and at 2:23, and that resulted in extraordinarily high homocysteine levels.

    Why was there so much B12 deficiency? Because only a small minority were taking a dedicated B12 supplement. And, unlike in the United States, B12 fortification of organic foods isn’t allowed in the United Kingdom. So, while U.S. soymilk and other products may be fortified with B12, UK products may not. We don’t see the same problem among U.S. vegans in the Adventist study, presumably because of the B12 fortification of commonly eaten foods in the United States. It may be no coincidence that the only study I was able to find that showed a significantly lower stroke mortality risk among vegetarians was an Adventist study.

    Start eating strictly plant-based without B12-fortified foods or supplements, and B12 deficiency can develop. However, that was only for those not eating sufficient foods fortified with B12. Those eating plant-based who weren’t careful about getting a regular reliable source of B12 had lower B12 levels and, consequently, higher homocysteine levels, as you can see below and at 3:27 in my video.

    The only way to prove vitamin B12 deficiency is a risk factor for cardiovascular disease in vegetarians is to put it to the test. When researchers measured the amount of atherosclerosis in the carotid arteries, the main arteries supplying the brain, “no significant difference” was found between vegetarians and nonvegetarians. They both looked just as bad even though vegetarians tend to have better risk factors, such as lower cholesterol and blood pressure. The researchers suggest that B12 deficiency plays a role, but how do they know? Some measures of artery function weren’t any better either. Again, they surmised that vitamin B12 deficiency was overwhelming the natural plant-based benefits. “The beneficial effects of vegetarian diets on lipids and blood glucose [cholesterol and blood sugars] need to be advocated, and efforts to correct vitamin B12 deficiency in vegetarian diets can never be overestimated.”

    Sometimes vegetarians did even worse. Worse artery wall thickness and worse artery wall function, “raising concern, for the first time, about the vascular health of vegetarians”—more than a decade before the new stroke study. Yes, their B12 was low, and, yes, their homocysteine was high, “suggest[ing] that vitamin B12 deficiency in vegetarians might have adverse effects on their vascular health.” What we need, though, is an interventional study, where participants are given B12 to see if that fixes it, and here we go. The title of this double-blind, placebo-controlled, randomized crossover study gives it away: “Vitamin B-12 Supplementation Improves Arterial Function in Vegetarians with Subnormal Vitamin B-12 Status.” So, compromised vitamin B12 status among those eating more plant-based diets due to not taking B12 supplements or regularly eating vitamin B12-fortified foods may explain the higher stroke risk found among vegetarians.

    Unfortunately, many vegetarians resist taking vitamin B12 supplements due to “misconceptions,” like “hold[ing] on to the old myth that deficiency of this vitamin is rare and occurs only in a small proportion of vegans.” “A common mistake is to think that the presence of dairy products and eggs in the diet, as in LOV [a lacto-ovo vegetarian diet], can still ensure a proper intake [of B12]…despite excluding animal flesh.”

    Now that we may have nailed the cause, maybe “future studies with vegetarians should focus on identifying ways to convince vegetarians to take vitamin B12 supplements to prevent a deficiency routinely.” 

    I have updated my recommendation for B12 supplementation. I now suggest at least 2,000 mcg (µg) of cyanocobalamin once weekly, ideally as a chewable, sublingual, or liquid supplement taken on an empty stomach, or at least 50 mcg daily of supplemental cyanocobalamin. (You needn’t worry about taking too much.) You can also have servings of B12-fortified foods three times a day (at each meal), each containing at least 190% of the Daily Value listed on the nutrition facts label. (Based on the new labeling mandate that started on January 1, 2020, the target is 4.5 mcg three times a day.) Please note, though, that those older than the age of 65 have only one option: to take 1,000 micrograms a day. 

    We started this series on what to eat and not eat for stroke prevention, and whether vegetarians really have a higher stroke risk. Check related posts for the last few videos that looked at specific factors.

    Stay tuned for: 

    Michael Greger M.D. FACLM

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  • What About Animal Protein and Vegetarians’ Stroke Risk?  | NutritionFacts.org

    What About Animal Protein and Vegetarians’ Stroke Risk?  | NutritionFacts.org

    Might animal protein-induced increases in the cancer-promoting growth hormone IGF-1 help promote brain artery integrity? 

    In 2014, a study on stroke risk and dietary protein found that greater intake was associated with lower stroke risk and, further, that the animal protein appeared particularly protective. Might that help explain why, as shown in the graph below and at 0:31 in my video Vegetarians and Stroke Risk Factors: Animal Protein?, vegetarians were recently found to have a higher stroke rate than meat eaters?

    Animal protein consumption increases the levels of a cancer-promoting growth hormone in the body known as IGF-1, insulin-like growth factor 1, which “accelerates the progression of precancerous changes to invasive lesions.” High blood concentrations are associated with increased risks of breast, colorectal, lung, and prostate cancers, potentially explaining the association between dairy milk intake and prostate cancer risk, for example. However, there are also IGF-1 receptors on blood vessels, so perhaps IGF-1 promotes cancer and brain artery integrity.

    People who have strokes appear to have lower blood levels of IGF-1, but it could just be a consequence of the stroke rather than the cause. There weren’t any prospective studies over time until 2017 when researchers found that, indeed, higher IGF-1 levels were linked to a lower risk of stroke—but is it cause and effect? In mice, the answer seems to be yes, and in a petri dish, IGF-1 appears to boost the production of elastin, a stretchy protein that helps keep our arteries elastic. As you can see in the graph below and at 1:41 in my video, higher IGF-1 levels are associated with less artery stiffness, but people with acromegaly, like Andre the Giant, those with excessive levels of growth hormones like IGF-1, do not appear to have lower stroke rates, and a more recent study of dietary protein intake and risk of stroke that looked at a dozen studies of more than half a million people (compared to only seven studies with a quarter million in the previous analysis), found no association between dietary protein intake and the risk of stroke. If anything, dietary plant protein intake may decrease the risk of stroke. 

    However, those with high blood pressure who have low IGF-1 levels do appear to be at increased risk of developing atherosclerosis, which is the thickening of the artery walls leading up to the brain, but no such association was found in people with normal blood pressure. So, there may be “a cautionary lesson for vegans” here. Yes, a whole food, plant-based diet “can down-regulate IGF-1 activity” and may slow the human aging process, not to mention reduce the risk of some of the common cancers that plague the Western world. But, “perhaps the ‘take-home’ lesson should be that people who undertake to down-regulate IGF-1 activity [by cutting down on animal protein intake] as a pro-longevity measure should take particular care to control their blood pressure and preserve their cerebrovascular health [the health of the arteries in their brain] – in particular, they should keep salt intake relatively low while insuring an ample intake of potassium” to keep their blood pressures down. So, that means avoiding processed foods and avoiding added salt, and, in terms of potassium-rich foods, eating beans, sweet potatoes, and dark-green leafy vegetables. 

    Might this explain the higher stroke risk found among vegetarians? No—because dairy and egg whites are animal proteins, too. Only vegans have lower IGF-1 levels in both men and women, so low levels of IGF-1 can’t explain why higher rates of stroke were found in vegetarians. Then what is it? I think the best explanation for the mystery is something called homocysteine, which I cover next. 

    If you aren’t familiar with IGF-1, my videos Flashback Friday: Animal Protein Compared to Cigarette Smoking and How Not to Die from Cancer are good primers. 

    Beyond eating a plant-based diet, how else can we lower our blood pressure? Check out the chapter of hypertension in my book How Not to Die at your local public library. 

    This is the eighth video in a 12-part series on vegetarians’ stroke risk. If you missed any of the previous ones, check out the related posts below.

    Coming up, we turn to what I think is actually going on:

    Michael Greger M.D. FACLM

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  • What About Saturated Fat and Vegetarians’ Stroke Risk?  | NutritionFacts.org

    What About Saturated Fat and Vegetarians’ Stroke Risk?  | NutritionFacts.org

    How can we explain the drop in stroke risk as the Japanese diet became westernized with more meat and dairy?

    As Japan westernized, the country’s stroke rate plummeted, as you can see in the graph below and at 0:15 in my video Vegetarians and Stroke Risk Factors: Saturated Fat?

    Stroke had been a leading cause of death in Japan, but the mortality rate decreased sharply as they moved away from their traditional diets and started eating more like those in the West. Did the consumption of all that extra meat and dairy have a protective effect? After all, their intake of animal fat and animal protein was going up at the same time their stroke rates were going down, as shown below and at 0:35 in my video

    Commented a noted Loma Linda cardiology professor, “Protection from stroke by eating animal foods? Surely not!…Many vegetarians, like myself, have almost come to expect the data to indicate that they have an advantage, whatever the disease that is being considered. Thus, it is disquieting to find evidence in a quite different direction for at least one subtype of stroke.” 

    Can dietary saturated fat, like that found in meat and dairy, be beneficial in preventing stroke risk? There appeared to be a protective association—but only in East Asian populations, as you can see below and at 1:11 in my video

    High dietary saturated fat was found to be associated with a lower risk of stroke in Japanese but not in non-Japanese. So, what was it about the traditional Japanese diet that the westernization of their eating habits made things better when it came to stroke risk? Well, at the same time, their meat and dairy intake was going up, and their salt intake was going down, as you can see below and at 1:40. 

    The traditional Japanese diet was packed with salt. They had some of the highest salt intakes in the world, about a dozen spoonsful of salt a day. Before refrigeration became widely available, they ate all sorts of salted, pickled, and fermented foods from soy sauce to salted fish. In the areas with twice the salt intake, they had twice the stroke mortality, but when the salt intake dropped, so did the stroke death rates, because when the salt consumption went down, their blood pressure went down, too. High blood pressure is perhaps “the single most important potentially modifiable risk factor for stroke,” so it’s no big mystery why the westernization of the Japanese diet led to a drop in stroke risk.  

    When they abandoned their more traditional diets, their obesity rates went up and so did their diabetes and coronary artery disease, but, as they gave up the insanely high salt intake, their insanely high stroke rates correspondingly fell. 

    Stomach cancer is closely associated with excess salt intake. When you look at their stomach cancer rates, they came down beautifully as they westernized their diets away from salt-preserved foods, as you can see in the graph below and at 2:50 in my video

    But, of course, as they started eating more animal foods like dairy, their rates of fatal prostate cancer, for example, shot through the roof. Compared to Japan, the United States has 7 times more deaths from prostate cancer, 5 times more deadly breast cancer, 3 times more colon cancer and lymphoma mortality, and 6 to 12 times the death rate from heart disease, as you can see in the graph below and at 3:15 in my video. Yes, Japanese stroke and stomach cancer rates were higher, but they were also eating up to a quarter cup of salt a day. 

    That would seem to be the most likely explanation, rather than some protective role of animal fat. And, indeed, it was eventually acknowledged in the official Japanese guidelines for the prevention of cardiovascular disease: “Refrain from the consumption of large amounts of fatty meat, animal fat, eggs, and processed foods…”

    Now, one of the Harvard cohorts found a protective association between hemorrhagic strokes and both saturated fat and trans fat, prompting a “sigh of relief…heard throughout the cattle-producing Midwestern states,” even though the researchers concluded that, of course, we all have to cut down on animal fat and trans fat for the heart disease benefit. Looking at another major Harvard cohort, however, they found no such protective association for any kind of stroke, and when they put all the studies together, zero protection was found across the board, as you can see below and at 4:07 in my video

    Observational studies have found that higher LDL cholesterol seems to be associated with a lower risk of hemorrhagic stroke, raising the possibility that cholesterol may be “a double-edged sword,” by decreasing the risk of ischemic stroke but increasing the risk of hemorrhagic stroke. But low cholesterol levels in the aged “may be a surrogate for nutritional deficiencies…or a sign of debilitating diseases,” or perhaps the individuals were on a combination of cholesterol-lowering drugs and blood thinners, and that’s why we tend to see more brain bleeds in those with low cholesterol. You don’t know until you put it to the test.

    Researchers put together about two dozen randomized controlled trials and found that the lower your cholesterol, the better when it comes to overall stroke risk, with “no significant increase in hemorrhagic stroke risk with lower achieved low-density lipoprotein [LDL] cholesterol levels.”

    The genetic data appear mixed, with some suggesting a lifetime of elevated LDL would give you a higher hemorrhagic stroke risk, while other data suggest more of that double-edged sword effect. However, with lower cholesterol, “any possible excess of hemorrhagic [bleeding] stroke is greatly outweighed by the protective effect against ischaemic stroke,” the much more common clotting type of stroke, not to mention heart disease. It may be on the order of 18 fewer clotting strokes for every 1 extra bleeding stroke with cholesterol-lowering. 

    Does this explain the increased stroke risk found among vegetarians? Hemorrhagic stroke is the type of stroke that appeared higher in vegetarians, but the cholesterol levels in vegans were even lower, and, if anything, vegans trended towards a higher clotting stroke risk, so it doesn’t make sense. If there is some protective factor in animal foods, it is to be hoped that a diet can be found that still protects against the killer number one, heart disease, without increasing the risk of the killer number five, stroke. But, first, we have to figure out what that factor is, and the hunt continues. 

    Aren’t there studies suggesting that saturated fat isn’t as bad as we used to think? Check out: 

    Just like the traditional Japanese diet had a lot going for it despite having high sodium as the fatal flaw, what might be the Achilles’ heel of plant-based diets when it comes to stroke risk? 

    This is the seventh video in this stroke series. See the related posts below for the others.

    Michael Greger M.D. FACLM

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  • What About Vegan Junk Food and Vegetarians’ Stroke Risk?  | NutritionFacts.org

    What About Vegan Junk Food and Vegetarians’ Stroke Risk?  | NutritionFacts.org

    Just because you’re eating a vegetarian or vegan diet doesn’t mean you’re eating healthfully.

    “Plant-Based Diets Are Associated with a Lower Risk of Incident Cardiovascular Disease, Cardiovascular Disease Mortality, and All-Cause Mortality in a General Population of Middle-Aged Adults”: This study of a diverse sample of 12,000 Americans found that “progressively increasing the intake of plant foods by reducing the intake of animal foods is associated with benefits on cardiovascular health and mortality.” Still, regarding plant-based diets for cardiovascular disease prevention, “all plant foods are not created equal.” As you can see in the graph below and at 0:40 in my video Vegetarians and Stroke Risk Factors: Vegan Junk Food?, a British study found higher stroke risk in vegetarians. Were they just eating a lot of vegan junk food? 

    “Any diet devoid of animal food sources can be claimed to be a vegetarian [or vegan] diet; thus, it is important to determine” what is being eaten. One of the first things I look at when I’m trying to see how serious a population is about healthy eating is something that is undeniably, uncontroversially bad: soda, aka liquid candy. Anyone drinking straight sugar water doesn’t have health on top of mind.

    A large study was conducted of plant-based eaters in the United States, where people tend to cut down on meat for health reasons far more than for ethics, as you can see in the graph below and at 1:20 in my video.

    Researchers found that flexitarians drink fewer sugary beverages than regular meat eaters, as do pescatarians, vegetarians, and vegans, as you can see below and at 1:30.

    However, in the study from the United Kingdom where the increased stroke risk in vegetarians was found and where people are more likely to go veg or vegan for ethical reasons, researchers found that pescatarians drink less soda, but the vegetarians and vegans drink more, as shown in the graph below and at 1:44. 

    I’m not saying that’s why they had more strokes; it might just give us an idea of how healthfully they were eating. In the UK study, the vegetarian and vegan men and women ate about the same amounts of desserts, cookies, and chocolate, as you can see in the graph below and at 1:53. 

    They also consumed about the same total sugar, as shown below and at 2:02. 

    In the U.S. study, the average non-vegetarian is nearly obese, the vegetarians are a little overweight, and the vegans were the only ideal weight group. In this analysis of the UK study, however, everyone was about the same weight. The meat eaters were lighter than the vegans, as you can see below, and at 2:19 in my video. The EPIC-Oxford study seems to have attracted a particularly “health-conscious” group of meat eaters weighing substantially less than the general population. 

    Let’s look at some specific stroke-related nutrients. Dietary fiber appears to be beneficial for the prevention of cardiovascular disease, including stroke, and it seems the more, the better, as you can see in the graph below and at 2:43 in my video

    Based on studies of nearly half a million men and women, there doesn’t seem to be any upper threshold of benefit—so, again, “the more, the better.” At more than 25 grams of soluble fiber and 47 grams of insoluble dietary fiber, you can start seeing a significant drop in associated stroke risk. So, one could consider these values “as the minimal recommendable daily intake of soluble and insoluble fiber…to prevent stroke at a population level.” That’s what you see in people eating diets centered around minimally processed plant foods. Dean Ornish, M.D., got up around there with his whole food, plant-based diet. It might not be as much as we were designed to eat, based on the analyses of fossilized feces, but that’s about where we might expect significantly lower stroke risk, as shown below and at 3:25 in my video

    How much were the UK vegetarians getting? 22.1 grams. Now, in the UK, they measure fiber a little differently, so it may be closer to 30 grams, but that’s still not the optimal level for stroke prevention. It’s so little fiber that the vegetarians and vegans only beat out the meat eaters by about one or two bowel movements a week, as you can see below and at 3:48 in my video, suggesting the non-meat eaters were eating lots of processed foods. 

    The vegetarians were only eating about half a serving more of fruits and vegetables. Intake is thought to reduce stroke risk in part because of their potassium content, but the UK vegetarians at higher stroke risk were eating so few greens and beans that they couldn’t even match the meat eaters. The vegetarians (and the meat eaters) weren’t even reaching the recommended minimum daily potassium intake of 4,700 mg a day.

    What about sodium? “The vast majority of the available evidence indicates that elevated salt intake is associated with higher stroke risk…” There is practically a straight-line increase in the risk of dying from a stroke, the more salt you eat, as you can see in the graph below and at 4:29 in my video

    Even just lowering sodium intake by a tiny fraction every year could prevent tens of thousands of fatal strokes. “Reducing Sodium Intake to Prevent Stroke: Time for Action, Not Hesitation” was the title of the paper, but the UK vegetarians and vegans appeared to be hesitating, as did the other dietary groups. “All groups exceeded the advised less than 2400 mg daily sodium intake”—and that didn’t even account for salt added to the table! The American Heart Association recommends less than 1,500 mg a day. So, they were all eating a lot of processed foods. It’s no wonder the vegetarians’ blood pressures were only one or two points lower. High blood pressure is perhaps “the single most important potentially modifiable risk factor for stroke.” 

    What evidence do I have that the vegetarians’ and vegans’ stroke risk would go down if they ate more healthfully? Well, in rural Africa, where they were able to nail the fiber intake that our bodies were designed to get by eating so many whole, healthy plant foods—including fruits, vegetables, grains, greens, beans, and protein almost entirely from plant sources—not only was heart disease, our number one killer, “almost non-existent,” but so was stroke. It only surged up from nowhere “with the introduction of salt and refined foods” to their diet. 

    “It is notable that stroke and senile dementia appear to be virtually absent in Kitava, an Oceanic culture [near Australia] whose quasi-vegan traditional diet is very low in salt and very rich in potassium.” They ate fish a few times a week, but the other 95 percent or so of their diet was made up of vegetables, fruits, corn, and beans. They had an apparent absence of stroke, even despite their ridiculously high rates of smoking, 76 percent of men and 80 percent of women. We evolved by eating as little as less than an eighth of a teaspoon of salt a day, and our daily potassium consumption is thought to have been as high as 10,000 mg or so. We went from an unsalted, whole-food diet to eating salty, processed foods depleted of potassium whether we eat meat or not. 

    Caldwell Esselstyn at the Cleveland Clinic tried putting about 200 patients with established cardiovascular disease on a whole food, plant-based diet. Of the 177 who stuck with the diet, only a single patient went on to have a stroke in the subsequent few years, compared to a hundred-fold greater rate of adverse events, including multiple strokes and deaths in those who strayed from the diet. “This is not vegetarianism,” Esselstyn explains. Vegetarians can eat a lot of less-than-ideal foods, “such as milk, cream, butter, cheese, ice cream, and eggs. This new paradigm is exclusively plant-based nutrition.” 

    This entire train of thought—that the reason typical vegetarians don’t have better stroke statistics is because they’re not eating particularly stellar diets—may explain why they don’t have significantly lower stroke rates. However, it still doesn’t explain why they may have higher stroke rates. Even if they’re eating similarly crappy, salty, processed diets, at least they aren’t eating meat, which we know increases stroke risk. There must be something about vegetarian diets that so increases stroke risk that it offsets their inherent advantages. We’ll continue our hunt for the answer next. 

    From a medical standpoint, labels like vegan and vegetarian just tell me what you don’t eat. It’s like identifying yourself as a “No-Twinkie-tarian.” You don’t eat Twinkies? Great, but what’s the rest of your diet like? 

    What are the healthiest foods? Check out my Daily Dozen.

    To catch up on the rest of this series, see related posts below. 

    Michael Greger M.D. FACLM

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  • What About Omega-3s and Vegetarians’ Stroke Risk?  | NutritionFacts.org

    What About Omega-3s and Vegetarians’ Stroke Risk?  | NutritionFacts.org

    Does eating fish or taking fish oil supplements reduce stroke risk? 

    In my last video, we started to explore what might explain the higher stroke risk in vegetarians found in the EPIC-Oxford study. As you can see below and at 0:25 in my video Vegetarians and Stroke Risk Factors: Omega-3s?, vegetarians have a lower risk of heart disease and cardiovascular disease overall, but a higher risk of stroke. We looked into vitamin D levels as a potential mechanism, but that didn’t seem to be the reason. What about long-chain omega-3s, the fish fats like EPA and DHA? 

    Not surprisingly, their levels are found to be “markedly lower in vegetarians and particularly in vegans than in meat-eaters.” They’re about 30 percent lower in vegetarians and more than half as low in vegans, as you can see below and at 0:45 in my video

    According to “the most extensive systematic assessment of effects of omega-3 fats on cardiovascular health to date,” combining 28 randomized controlled trials, stroke has no benefit. There is evidence that taking fish oil “does not reduce heart disease, stroke or death,” or overall mortality, either. This may be because, on the one hand, the omega-3s may be helping, but the mercury in fish may be making things worse. “Balancing the benefits with the contaminant risks of fish consumption has represented a challenge for regulatory agencies and public health professionals.”  

    For example, dietary exposure to polychlorinated biphenyls (PCBs) may be associated with an increased risk of stroke. In one study, for instance, “neither fish nor intake of PCBs was related to stroke risk. However, with adjustment for fish intake,” that is, at the same fish intake, “dietary PCBs were associated with an increased risk of total stroke,” so the PCB pollutants may be masking the fish benefit. If we had a time machine and could go back before the Industrial Revolution and find fish in an unpolluted state, we might find that it is protective against stroke. Still, looking at the EPIC-Oxford study data, if fish were protective, then we might expect that the pescatarians (those who eat fish but no other meat) would have lower numbers of strokes since they would have the fish benefit without the risk from other meat. But, no. That isn’t the reality. So, it doesn’t seem to be the omega-3s either.

    Let’s take a closer look at what the vegetarians are eating.

    When it comes to plant-based diets for cardiovascular disease prevention, all plant foods are not created equal. There are two types of vegetarians—those who do it for their health, and those who do it for ethical reasons, like global warming or animals—and the latter tend to eat different diets. Health vegans tend to eat more fruits and fewer sweets, for instance, and you don’t tend to see them chomping down on vegan donuts, as shown below and at 2:41 in my video

    “Concerns about health and costs were primary motivations for [meat] reduction” in the United States. A middle-class American family is four times more likely to reduce meat for health reasons compared to environmental or animal welfare concerns, as you can see in the graph below and at 2:55 in my video

    But in the United Kingdom, where the EPIC-Oxford stroke study was done, ethics was the number one reason given for becoming vegetarian or vegan, as you can see in below and at 3:05 in my video.

    We know that “plant-based diets, diets that emphasize higher intakes of plant foods and lower intakes of animal foods, are associated with a lower risk of incident cardiovascular disease, cardiovascular disease mortality, and all-cause mortality”—a lower risk of dying from all causes put together—“in a general US adult population.” But, that’s only for healthy plant foods. Eating a lot of Wonder Bread, soda, and apple pie isn’t going to do you any favors. “For all types of plant-based diets, however, it is crucial that the choice of plant foods is given careful consideration.” We should choose whole fruits and whole grains over refined grains and avoid trans fats and added sugars. Could it be that the veggie Brits were just eating more chips? We’ll find out next. 

    Another strikeout trying to explain the increased risk. Could it be that the vegetarians were eating particularly unhealthy diets? Labels like vegetarian or vegan just tell me what is not being eaten. You can be vegetarian and consume a lot of unhealthy fare, like french fries, potato chips, and soda. That’s why, as a physician, I prefer the term whole food, plant-based nutrition. That tells me what you do eat. You eat vegetables and follow a diet centered around the healthiest foods out there.

    If you missed the first four videos in this series, see:

     Surprised about the fishy oil findings? Learn more: Is Fish Oil Just Snake Oil? and Omega-3s and the Eskimo Fish Tale

    Michael Greger M.D. FACLM

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  • What About Vitamin D and Vegetarians’ Stroke Risk?  | NutritionFacts.org

    What About Vitamin D and Vegetarians’ Stroke Risk?  | NutritionFacts.org

    Could the apparent increased stroke risk in vegetarians be reverse causation? And what about vegetarians versus vegans? 

    In the “Risks of Ischaemic Heart Disease and Stroke in Meat Eaters, Fish Eaters, and Vegetarians Over 18 Years of Follow-Up” EPIC-Oxford study, not surprisingly, vegetarian diets were associated with less heart disease—10 fewer cases per 1,000 people per decade compared to meat eaters—but vegetarian diets were associated with three more cases of stroke. So, eating vegetarian appears to lower the risk of cardiovascular disease by 7 overall, but why the extra stroke risk? Could it just be reverse causation?

    When studies have shown higher mortality among those who quit smoking compared to people who continue to smoke, for example, we suspect “reverse causality.” When we see a link between quitting smoking and dying, instead of quitting smoking leading to people dying, it’s more likely that being “affected by some life-threatening condition” led people to quit smoking. It’s the same reason why non-drinkers can appear to have more liver cirrhosis; their failing liver led them to stop drinking. This is the “sick-quitter effect,” and you can see it when people quit meat, too.

    As you can see below and at 1:16 in my video Vegetarians and Stroke Risk Factors: Vitamin D?

    , new vegetarians can appear to have more heart disease than non-vegetarians. Why might an older person all of a sudden start eating vegetarian? Well, they may have just been diagnosed with heart disease, so that may be why there appear to be higher rates for new vegetarians—an example of the sick-quitter effect. To control for that, you can throw out the first five years of data to make sure the diet has a chance to start working. And, indeed, when you do that, the true effect is clear: a significant drop in heart disease risk. 

    So, does that explain the apparent increased stroke risk, too? No, because researchers still found higher stroke risk even after the first five years of data were skipped. What’s going on? Let’s dive deeper into the data to look for clues.

    What happens when you break down the results by type of stroke and type of vegetarian (vegetarian versus vegan)? As you can see below and at 2:09 in my video, there are two main types of strokes—ischemic and hemorrhagic. Most common are ischemic, clotting strokes where an artery in the brain gets clogged off, as opposed to hemorrhagic, or bleeding strokes, where a blood vessel in the brain ruptures. In the United States, for example, it is about 90:10, with nine out of ten strokes the clotting (ischemic) type and one out of ten bleeding (hemorrhagic), the latter being the kind of stroke vegetarians appeared to have significantly more of. Now, statistically, the vegans didn’t have a significantly higher risk of any kind of stroke, but that’s terrible news for vegans. Do vegans have the same stroke risk as meat eaters? What is elevating their stroke risk so much that it’s offsetting all their natural advantages? The same could be said for vegetarians, too. 

    Even though this was the first study of vegetarian stroke incidence, there have been about half a dozen studies on stroke mortality. The various meta-analyses have consistently found significantly lower heart disease risk for vegetarians, but the lower stroke mortality was not statistically significant. Now, there is a new study that can give vegetarians some comfort in the fact that they at least don’t have a higher risk of dying from stroke, but that’s terrible news for vegetarians. Statistically, vegetarians have the same stroke death rate as meat eaters. Again, what’s going on? What is elevating their stroke risk so much that it’s offsetting all their natural advantages?

    Let’s run through a couple of possibilities. As you can see in the graph below and at 3:48 in my video, if you look at the vitamin D levels of vegetarians and vegans, they tend to run consistently lower than meat eaters, and lower vitamin D status is associated with an increased risk of stroke. But who has higher levels of the sunshine vitamin? Those who are running around outside and exercising, so maybe that’s why their stroke risk is better. What we need are randomized studies.

    When you look at people who have been effectively randomized at birth to genetically have lifelong, lower vitamin D levels, you do not see a clear indicator of increased stroke risk, so the link between vitamin D and stroke is probably not cause-and-effect.

    We’ll explore some other possibilities, next.

    So far in this series, we’ve looked at what to eat and what not to eat for stroke prevention, and whether vegetarians do have a higher stroke risk

    It may be worth reiterating that vegetarians do not have a higher risk of dying from a stroke, but they do appear to be at higher risk of having a stroke. How is that possible? Meat is a risk factor for stroke, so how could cutting out meat lead to more strokes? There must be something about eating plant-based that so increases stroke risk that it counterbalances the meat-free benefit. Might it be because plant-based eaters don’t eat fish? We turn to omega-3s next. For other videos in this series, see related posts below. 

    There certainly are benefits to vitamin D, though. Here is a sampling of videos where I explore the evidence.

    Michael Greger M.D. FACLM

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  • The Stroke Risk of Vegetarians  | NutritionFacts.org

    The Stroke Risk of Vegetarians  | NutritionFacts.org

    The first study in history on the incidence of stroke in vegetarians and vegans suggests they may be at higher risk.

    “When ranked in order of importance, among the interventions available to prevent stroke, the three most important are probably diet, smoking cessation, and blood pressure control.” Most of us these days are doing pretty good about not smoking, but less than half of us exercise enough. And, according to the American Heart Association, only 1 in 1,000 Americans is eating a healthy diet and less than 1 in 10 is even eating a moderately healthy diet, as you can see in the graph below and at 0:41 in my video Do Vegetarians Really Have Higher Stroke Risk?. Why does it matter? It matters because “diet is an important part of stroke prevention. Reducing sodium intake, avoiding egg yolks, limiting the intake of animal flesh (particularly red meat), and increasing the intake of whole grains, fruits, vegetables, and lentils….Like the sugar industry, the meat and egg industries spend hundreds of millions of dollars on propaganda, unfortunately with great success.” 

    The paper goes on to say, “Box 1 provides links to information about the issue.” I was excited to click on the hyperlink for “Box 1” and was so honored to see four links to my videos on egg industry propaganda, as you can see below and at 1:08 in my video

    The strongest evidence for stroke protection lies in increasing fruit and vegetable intake, with more uncertainty regarding “the role of whole grains, animal products, and dietary patterns,” such as vegetarian diets. One would expect meat-free diets would do great. Meta-analyses have found that vegetarian diets lower cholesterol and blood pressure, as well as enhance weight loss and blood sugar control, and vegan diets may work even better. All the key biomarkers are going in the right direction. Given this, you may be surprised to learn that there hadn’t been any studies on the incidence of stroke in vegetarians and vegans until now. And if you think that is surprising, wait until you hear the results. 

    “Risks of Ischaemic Heart Disease and Stroke in Meat Eaters, Fish Eaters, and Vegetarians Over 18 Years of Follow-Up: Results from the Prospective EPIC-Oxford Study”: There was less heart disease among vegetarians (by which the researchers meant vegetarians and vegans combined). No surprise. Been there, done that. But there was more stroke, as you can see below, and at 2:14 in my video

    An understandable knee-jerk reaction might be: Wait a second, who did this study? Was there a conflict of interest? This is EPIC-Oxford, world-class researchers whose conflicts of interest may be more likely to read: “I am a member of the Vegan Society.”

    What about overadjustment? When the numbers over ten years were crunched, the researchers found 15 strokes for every 1,000 meat eaters, compared to only 9 strokes for every 1,000 vegetarians and vegans, as you can see below and at 2:41 in my video. In that case, how can they say there were more strokes in the vegetarians? This was after adjusting for a variety of factors. The vegetarians were less likely to smoke, for example, so you’d want to cancel that out by adjusting for smoking to effectively compare the stroke risk of nonsmoking vegetarians to nonsmoking meat eaters. If you want to know how a vegetarian diet itself affects stroke rates, you want to cancel out these non-diet-related factors. Sometimes, though, you can overadjust

    The sugar industry does this all the time. This is how it works: Imagine you just got a grant from the soda industry to study the effect of soda on the childhood obesity epidemic. What could you possibly do after putting all the studies together to conclude that there was a “near zero” effect of sugary beverage consumption on body weight? Well, since you know that drinking liquid candy can lead to excess calories that can lead to obesity, if you control for calories, if you control for a factor that’s in the causal chain, effectively only comparing soda drinkers who take in the same number of calories as non-soda-drinkers, then you could undermine the soda-to-obesity effect, and that’s exactly what they did. That introduces “over adjustment bias.” Instead of just controlling for some unrelated factor, you control for an intermediate variable on the cause-and-effect pathway between exposure and outcome.

    Overadjustment is how meat and dairy industry-funded researchers have been accused of “obscuring true associations” between saturated fat and cardiovascular disease. We know that saturated fat increases cholesterol, which increases heart disease risk. Therefore, if you control for cholesterol, effectively only comparing saturated fat eaters with the same cholesterol levels as non-saturated-fat eaters, that could undermine the saturated fat-to-heart disease effect.

    Let’s get back to the EPIC-Oxford study. Since vegetarian eating lowers blood pressure and a lowered blood pressure leads to less stroke, controlling for blood pressure would be an overadjustment, effectively only comparing vegetarians to meat eaters with the same low blood pressure. That’s not fair, since lower blood pressure is one of the benefits of vegetarian eating, not some unrelated factor like smoking. So, that would undermine the afforded protection. Did the researchers do that? No. They only adjusted for unrelated factors, like education, socioeconomic class, smoking, exercise, and alcohol. That’s what you want. You want to tease out the effects of a vegetarian diet on stroke risk. You want to try to equalize everything else to tease out the effects of just the dietary choice. And, since the meat eaters in the study were an average of ten years older than the vegetarians, you can see how vegetarians could come out worse after adjusting for that. Since stroke risk can increase exponentially with age, you can see how 9 strokes among 1,000 vegetarians in their 40s could be worse than 15 strokes among 1,000 meat-eaters in their 50s. 

    The fact that vegetarians had greater stroke risk despite their lower blood pressure suggests there’s something about meat-free diets that so increases stroke risk it’s enough to cancel out the blood pressure benefits. But, even if that’s true, you would still want to eat that way. As you can see in the graph below and at 6:16 in my video, stroke is our fifth leading cause of death, whereas heart disease is number one. 

    So, yes, in the study, there were more cases of stroke in vegetarians, but there were fewer cases of heart disease, as you can see below and at 6:29. If there is something increasing stroke risk in vegetarians, it would be nice to know what it is in hopes of figuring out how to get the best of both worlds. This is the question we will turn to next. 

    I called it 21 years ago. There’s an old video of me on YouTube where I air my concerns about stroke risk in vegetarians and vegans. (You can tell it’s from 2003 by my cutting-edge use of advanced whiteboard technology and the fact that I still had hair.) The good news is that I think there’s an easy fix.

    This is the third in a 12-video series on stroke risk. Links to the others are in the related posts below.

    Michael Greger M.D. FACLM

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  • Eating to Lower Lp(a)  | NutritionFacts.org

    Eating to Lower Lp(a)  | NutritionFacts.org

    What should we eat—and not eat—to lower the cardiovascular disease risk factor lipoprotein(a)?

    Lipoprotein A, also known as Lp(a), is an independent, genetic, and causal factor for cardiovascular disease and heart attacks. At any level of LDL cholesterol, our risk of heart attack and stroke is two- to three-fold higher when our Lp(a) is elevated. With a high enough Lp(a) level, atherosclerosis continues to progress even if we get our LDL cholesterol way down, which may help explain why so many people continue to have heart attacks and strokes even under treatment for high cholesterol. It’s been suggested that “it would be worthwhile to check Lp(a) levels in a patient who has suffered an event but has no traditional risk factors to explain it.” What’s the point of checking it, though, if there isn’t much we can do about it? “To date, no drug to reduce circulating Lp(a) levels has been approved for clinical use.”

    Some researchers blame our lack of knowledge on the fact that Lp(a) is not found in typical lab animals, like rats and mice. It’s only found in two places in nature: primates and hedgehogs. Hedgehogs? How strange is that? No wonder Lp(a) is “an enigmatic protein that has mystified medical scientists ever since” it was first discovered more than half a century ago. But who needs mice when you have men? The level in our bloodstream is “primarily determined” by genetics. For the longest time, Lp(a) was not thought to be significantly influenced by factors such as diet. Given its similarity to LDL, though, one might assume lifestyle changes, “such as increased physical activity or the adoption of a healthy diet,” would help. “However, the effects of these interventions on Lp(a) concentrations are so far either only marginal or lacking in evidence,” but might that be because they have not tried a plant-based diet yet?

    As I discuss in my video How to Lower Lp(a) with Diet, when it comes to raising LDL cholesterol, we’ve known for years that the trans fats found in meat and dairy are just as bad as the industrially produced trans fats found in partially hydrogenated oil and junk food. But, when it comes to Lp(a), as you can see below and at 2:05 in my video, trans fats from meat and dairy appear to be even worse. 

    Just cutting out meat and following a lacto-ovo vegetarian diet did not appear to help, but, as you can see below and at 2:19 in my video, when study participants were put on a whole food, plant-based diet packed with a dozen servings of fruits and vegetables a day, their Lp(a) levels dropped by 16 percent within four weeks. 

    Of course, in those 30 days, the study subjects also lost about 15 pounds, as you can see below and at 2:28, but weight loss does not appear to affect Lp(a) levels, so you figure that it must have been due to the diet. 

    If you’re already eating a healthy plant-based diet and your Lp(a) levels are still too high, are there any particular foods that can help? As with cholesterol, even if the average total cholesterol of those eating strictly plant-based may be right on target at less than 150, with an LDL under 70, there’s a bell curve with plus or minus 30 points that fall on either side, as you can see below and at 2:45 in my video

    Enter the “Portfolio Diet,” which is not only plant-based, but also adds specific cholesterol-lowing foods—so, think nuts, beans, oatmeal, and berries to drag cholesterol down even further. The infographic is below and at 3:11 in my video.  

    What about Lp(a)? Nuts have been put to the test. Two and a half ounces of almonds every day dropped levels, but only by about 8 percent. That is better than another nut study, though, that found no effect at all, as you can see below and at 3:29 in my video. An additional study found “no significant changes,” and researchers reported that subjects in their study “did not experience a change in Lp(a).” Ah, nuts.  

    There is one plant that appears to drop Lp(a) levels by 20 percent, which is enough to take people exceeding the U.S. cut-off down to a more optimum level. And that plant is a fruit: Emblica officinalis, otherwise known as amla or Indian gooseberry. A randomized, double-blind, placebo-controlled study asked smokers before and after the trial about their “mouth hygiene, cough with expectoration, shortness of breath on exertion, loss of appetite, feelings of impending doom, palpitation, sleep deprivation, irritability, heartburn and tiredness,” as well as such objective measurements as their blood count, cholesterol, DNA damage, antioxidant status, and lung function. The amla extract used “showed a significant improvement compared to the placebo group in all the subjective and objective parameters tested with no reports of adverse events.” No side effects at all. That’s unbelievable! No, that’s unbelievable. And indeed, it’s completely not true.  

    Yes, subjective complaints got better in the amla group, but they got better in the placebo group, too, with arbitrary scoring systems and no statistical analysis whatsoever. And, of the two dozen objective measures, only half could be said to reach any kind of before-and-after statistical significance and only three were significant enough to account for the fact that if you measure two dozen things, a few might pop up as positive if only by chance. Any time you see this kind of spin in the abstract, which is sometimes the only part of a study people read, you should suspect some kind of conflict of interest. However, no conflicts of interest were declared by the researchers, but that’s bullsh*t, as the study was funded by the very company selling those amla supplements! Sigh.

    Anyway, one of those three significant findings was the Lp(a), so it might be worth a try in the context of a plant-based diet, which, in addition to helping with weight loss, can dramatically improve blood pressure (even after cutting down on blood pressure medications) and contribute to a 25-point drop in LDL cholesterol. Also, it may contribute to a 30 percent drop in C-reactive protein and significant reductions in other inflammatory markers for “a systemic, cardio-protective effect”—all thanks to this single dietary approach.

    You may be interested in my video on Trans Fat in Meat and Dairy. Did you know that animal products are exempted from the ban? See Banning Trans Fat in Processed Foods but Not Animal Fat.

    For more on amla and what else it can do, check out the related posts below.

    If you missed my previous video on Lp(a), watch Treating High Lp(a)—A Risk Factor for Atherosclerosis

    Michael Greger M.D. FACLM

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  • Headache and Migraine Relief from Foods  | NutritionFacts.org

    Headache and Migraine Relief from Foods  | NutritionFacts.org

    Plant-based diets are put to the test for treating migraine headaches.

    Headaches are one of the top five reasons people end up in emergency rooms and one of the leading reasons people see their doctors in general. One way to try to prevent them is to identify their triggers and avoid them. Common triggers for migraines include stress, smoking, hunger, sleep issues, certain foods (like chocolate, cheese, and alcohol), your menstrual cycle, or certain weather patterns (like high humidity).

    In terms of dietary treatments, the so-called Father of Modern Medicine, William Osler suggested trying a “strict vegetable diet.” After all, the nerve inflammation associated with migraines “may be reduced by a vegan diet as many plant foods are high in anti-inflammatory compounds and antioxidants, and likewise, meat products have been reported to have inflammatory properties.” It wasn’t put to the test, though, for another 117 years.

    As I discuss in my video Friday Favorites: Foods That Help Headache and Migraine Relief, among study participants given a placebo supplement, half said they got better, while the other half said they didn’t. But, when put on a strictly plant-based diet, they did much better, experiencing a significant drop in the severity of their pain, as you can see in the graph below and at 1:08 in my video

    Now, “it is possible that the pain-reducing effects of the vegan diet may be, at least in part, due to weight reduction.” The study participants lost about nine more pounds when they were on the plant-based diet for a month, as shown below, and at 1:22. 

    Even just lowering the fat content of the diet may help. Those placed on a month of consuming less than 30 daily grams of fat (for instance, less than two tablespoons of oil all day), experienced “statistically significant decreases in headache frequency, intensity, duration, and medication intake”—a six-fold decrease in the frequency and intensity, as you can see below and at 1:44 in my video. They went from three migraine attacks every two weeks down to just one a month. And, by “low fat,” the researchers didn’t mean SnackWell’s; they meant more fruits, vegetables, and beans. Before the food industry co-opted and corrupted the term, eating “low fat” meant eating an apple, for example, not Kellogg’s Apple Jacks.  

    Now, they were on a low-fat diet—about 10 percent fat for someone eating 2,500 calories a day. What about just less than 20 percent fat compared to a more normal diet that’s still relatively lower fat than average? As you can see below and at 2:22 in my video, the researchers saw the same significant drops in headache frequency and severity, including a five-fold drop in attacks of severe pain. Since the intervention involved at least a halving of intake of saturated fat, which is mostly found in meat, dairy, and junk, the researchers concluded that reduced consumption of saturated fat may help control migraine attacks—but it isn’t necessarily something they’re getting less of. There are compounds “present in Live green real veggies” that might bind to a migraine-triggering peptide known as calcitonin gene-related peptide, CGRP. 

    Drug companies have been trying to come up with something that binds to CGRP, but the drugs have failed to be effective. They’re also toxic, which is a problem we don’t have with cabbage, as you can see below and at 3:01 in my video

    Green vegetables also have magnesium. Found throughout the food supply but most concentrated in green leafy vegetables, beans, nuts, seeds, and whole grains, magnesium is the central atom to chlorophyll, as shown below and at 3:15. So, you can see how much magnesium foods have in the produce aisle by the intensity of their green color. Although magnesium supplements do not appear to decrease migraine severity, they may reduce the number of attacks you get in the first place. You can ask your doctor about starting 600 mg of magnesium dicitrate every day, but note that magnesium supplements can cause adverse effects, such as diarrhea, so I recommend getting it the way nature intended—in the form of real food, not supplements.  

    Any foods that may be particularly helpful? You may recall that I’ve talked about ground ginger. What about caffeine? Indeed, combining caffeine with over-the-counter painkillers, like Tylenol, aspirin, or ibuprofen, may boost their efficacy, at doses of about 130 mg for tension-type headaches and 100 mg for migraines. That’s about what you might expect to get in three cups of tea, as you can see below, and at 4:00 in my video. (I believe it is just a coincidence that the principal investigator of this study was named Lipton.) 

    Please note that you can overdo it. If you take kids and teens with headaches who were drinking 1.5 liters of cola a day and cut the soda, you can cure 90 percent of them. However, this may be a cola effect rather than a caffeine effect. 

    And, finally, one plant food that may not be the best idea is the Carolina Reaper, the hottest chili pepper in the world. It’s so mind-numbingly hot it can clamp off the arteries in your brain, as seen below and at 4:41 in my video, and you can end up with a “thunderclap headache,” like the 34-year-old man who ate the world’s hottest pepper and ended up in the emergency room. Why am I not surprised it was a man? 

    I’ve previously covered ginger and topical lavender for migraines. Saffron may help relieve PMS symptoms, including headaches. A more exotic way a plant-based diet can prevent headaches is by helping to keep tapeworms out of your brain.

    Though hot peppers can indeed trigger headaches, they may also be used to treat them. Check out my video on relieving cluster headaches with hot sauce

    Michael Greger M.D. FACLM

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  • Is All Vegan Food Healthy?  | NutritionFacts.org

    Is All Vegan Food Healthy?  | NutritionFacts.org

    How do healthier plant-based diets compare to unhealthy plant foods and animal foods when it comes to diabetes risk? 

    In my video on flexitarians, I discuss how the benefits of eating a plant-based diet are not all-or-nothing. “Simple advice to increase the consumption of plant-derived foods with compensatory [parallel] reductions in the consumption of foods from animal sources confers a survival advantage”— a live-longer advantage. The researchers call it a “pro-vegetarian” eating pattern, one that’s moving in the direction of vegetarianism, “a more gradual and gentle approach.” 

    If you’re dealing with a serious disease, though, like diabetes, completely “avoiding some problem foods is easier than attempting to moderate their intake. Clinicians would never tell an alcoholic to try to simply cut down on alcohol. Avoiding alcohol entirely is more effective and, in fact, easier for a problem drinker…Paradoxically, asking patients to make a large change may be more effective than making a slow transition. Diet studies show that recommending more significant changes increases the chances that patients can accomplish [them]. It may help to replace the common advice, ‘all things in moderation’ with ‘big changes beget big results.’ Success breeds success. After a few days or weeks of major dietary changes, patients are likely to see improvements in weight and blood glucose [sugar] levels—improvements that reinforce the dietary changes that elicited them. Furthermore, they may enjoy other health benefits of a plant-based diet” that may give them further motivation. 

    As you can see below and at 1:43 in my video Friday Favorites: Is Vegan Food Always Healthy?, those who choose to eat plant-based for their health say it’s mostly for “general wellness or general disease prevention” or to improve their energy levels or immune function, for example. 

    They felt it gives them a sense of control over their health, helps them feel better emotionally, improves their overall health, makes them feel better, and more, as shown below and at 1:48. Most felt it was very important for maintaining their health and well-being. 

    For the minority who used it for a specific health problem, mostly high cholesterol or weight loss, followed by high blood pressure and diabetes, most reported they felt it helped a great deal, as you can see below and at 2:14. 

    Some choose plant-based diets for other reasons, such as animal welfare or global warming, and it looks like “ethical vegans” are more likely to eat sugary and fatty foods, like vegan donuts, compared to those eating plant-based because of religious or health concerns, as you can see below and at 2:26 in my video

    The veganest vegan could make an egg- and dairy-free cake, covered with frosting, marshmallow fluff, and chocolate syrup, topped with Oreos, and served with a side of Doritos. Or, they may want fruit for dessert, but in the form of Pop-Tarts and Krispy Kreme pies. Vegan, yes. Healthy, no. 

    “Plant-based diets have been recommended to reduce the risk of type 2 diabetes (T2D). However, not all plant foods are necessarily beneficial.” In the pro-vegetarian scoring system I mentioned above, you get points for eating potato chips and French fries because they are technically plant-based, as you can see below and at 3:07 in my video, but Harvard researchers wanted to examine the association of not only an overall plant-based diet, but healthy and unhealthy versions. So, they created the same kind of pro-vegetarian scoring system, but it was weighted towards any sort of plant-based foods and against animal foods; then, they created a healthful plant-based diet index, where at least some whole plant foods took precedence and Coca-Cola and other sweetened beverages were no longer considered plants. Lastly, they created an unhealthful plant-based diet index by assigning positive scores to processed plant-based junk and negative scores for healthier plant foods and animal foods. 

    Their findings? As you can see below and at 3:51 in my video, a more plant-based diet, in general, was good for reducing diabetes risk, but eating especially healthy plant-based foods did better, nearly cutting risk in half, while those eating more unhealthy plant foods did worse, as shown in the graph below and at 4:03.

    Now, is that because they were also eating more animal foods? People often eat burgers with their fries, so the researchers separated the effects of healthy plant foods, less healthy plant foods, and animal foods on diabetes risk. And, they found that healthy plant foods were protectively associated, animal foods were detrimentally associated, and less healthy plant foods were more neutral when it came to diabetes risk. Below and at 4:32 in my video, you can see the graph that shows higher diabetes risk with more and more animal foods, no protection whatsoever with junky plant foods, and lower and lower diabetes risk associated with more and more healthy whole plant foods in the diet. So, they concluded that, yes, “plant-based diets…are associated with substantially lower risk of developing T2D.” However, it may not be enough to just lower the intake of animal foods; consumption of less healthy plant foods may need to decrease, too. 

    As a physician, labels like vegetarian and vegan just tell me what you don’t eat, but there are a lot of unhealthy vegetarian fare like French fries, potato chips, and soda pop. That’s why I prefer the term whole food and plant-based nutrition. That tells me what you do eat—a diet centered around the healthiest foods out there. 

    The video I mentioned is Do Flexitarians Live Longer?

    You may also be interested in some of my past popular videos and blogs on plant-based diets. Check related posts below. 

    Michael Greger M.D. FACLM

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  • The Pros of Garlic Powder for Heart Disease  | NutritionFacts.org

    The Pros of Garlic Powder for Heart Disease  | NutritionFacts.org

    See what a penny a day’s worth of garlic powder can do.

    In ancient Greece, “the Art of Medicine was divided into three parts”: cures through diet, cures through drugs, and cures through surgery. Garlic, Hippocrates wrote, was one such medicinal food, but that was to treat a nonexistent entity called “displacement of the womb,” so ancient wisdom can only go so far.

    Those who eat more than a clove of garlic a day do seem to have better artery function than those who eat less than that, but you don’t know if it’s cause-and-effect until you put it to the test. 

    As I discuss in my video Benefits of Garlic Powder for Heart Disease, heart disease patients were randomized to receive either garlic powder or placebo tablets two times a day for three months. Those lucky enough to be in the garlic group got a significant boost in their artery function—a 50 percent increase in function from taking only 800 mg of garlic powder a day. That’s just a quarter teaspoon of garlic powder. A 50 percent increase in artery function for less than a penny daily!

    If regular, plain old garlic powder can do that, what about those fancy Kyolic® aged garlic extract supplements? They can be 30 times more expensive and don’t work at all. After four weeks, there was zero significant improvement. It’s hard to improve on Mother Nature.

    Garlic powder can improve the function of our arteries, but what about the structure of our arteries? Dozens of studies on garlic all compiled together show that garlic can reduce cholesterol levels in the blood by more than 16 points. So, might garlic powder actually be able to slow the progression of atherosclerosis? Researchers studied a garlic powder tablet versus a placebo for three months. As you can see below and at 1:42 in my video, the placebo group got worse, which is what tends to happen. Eat the same artery-clogging diet, and your arteries continue to clog. However, the progression of the disease appeared to slow and even stall in the garlic group. 

    Of course, it would be nice to see the thickening of the artery wall reverse, but, for that, one might have to add more plants than just garlic to one’s diet. Still, though, that same quarter teaspoon of a simple spice available everywhere may be considered as an adjunct treatment for atherosclerosis, the number one killer of both men and women in the United States and around much of the world.

    What about garlic for high blood pressure? A systematic review and meta-analysis of randomized controlled trials “demonstrated that garlic has a statistically significant and clinically meaningful effect” on both systolic and diastolic blood pressures, reducing the top number by nearly seven and the bottom number by about five. That may not sound like a lot, but reducing diastolic blood pressure (the bottom number) by five points can reduce the risk of stroke by about a third and heart disease by 25 percent, as you can see in the graph below and at 2:38 in my video

    “Plant-based medicine provides beneficial effects, alongside with only minimal or no complications”—that is, little or no side effects—“and compared to other medicine are relatively cost-effective.” I’d say so, at as little as a penny per day.

    What else can garlic do? See related posts below.

    Here’s a tasty, garlicky recipe from The How Not to Die Cookbook: Garlic Caesar Salad Dressing

    Of course, the best way to treat heart disease is to simply get rid of it by treating the underlying cause. See How Not to Die from Heart Disease.

    Michael Greger M.D. FACLM

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  • A Look at the 5:2 Diet and the Fasting-Mimicking Diet  | NutritionFacts.org

    A Look at the 5:2 Diet and the Fasting-Mimicking Diet  | NutritionFacts.org

    What are the effects of eating only five days a week or following a fasting-mimicking diet five days a month? 
     
    Instead of eating every other day, what if you ate five days a week and fasted for the other two? As I discuss in my video The 5:2 Diet and the Fasting-Mimicking Diet Put to the Test, the available data are similar to that of alternate-day fasting: About a dozen pounds of weight loss was reported in overweight men and also reported in overweight women over six months, with no difference found between participants on the 5:2 intermittent fasting regimen and those on a continuous 500-calories-a-day restriction. The largest trial to date found an 18-pound weight loss within six months in the 5:2 group, which isn’t significantly different from the 20 pounds lost in the continuous calorie restriction group. Weight maintenance over the subsequent six months was also found to be no different.
     
    Though feelings of hunger may be more pronounced on the 5:2 pattern than on an equivalent level of daily calorie cutting, it does not seem to lead to overeating on non-fasting days. One might expect going two days without food may negatively impact mood, but no such adverse impact was noted for those fully fasting on zero calories or sticking to just two packets of oatmeal on each of the “fasting” days. (The oatmeal provides about 500 calories a day.) Like alternate-day fasting, the 5:2 fasting pattern appeared to have inconsistent effects on cognition and on preserving lean mass, and it also failed to live up to the “popular notion” that intermittent fasting would be “easier” to adhere to than daily calorie restriction. 
     
    Compared to those in the continuous-restriction control group, fewer subjects in the 5:2 pattern group expressed interest in continuing their diet after the study was over. This was attributed to quality-of-life issues, with 5:2 fasting participants citing headaches, lack of energy, and difficulty fitting the fasting days into their weekly routine. However, as you can see below and at 1:53 in my video, there has yet to be a single 5:2 diet study showing elevated LDL cholesterol compared with continuous calorie restriction at six months. Nor has it been shown for a year. This offers a potential advantage over alternate-day regimens. 

    Instead of 5:2, what about 25:5, spending five consecutive days a month on a “fasting-mimicking diet” (FMD)? Longevity researcher Valter Longo designed a five-day meal plan to try to simulate the metabolic effects of fasting by being low in protein, sugars, and calories with zero animal protein and zero animal fat. By making the diet plant-based, he hoped to lower the level of the cancer-promoting growth hormone IGF-1. He indeed accomplished this goal, along with a drop in markers of inflammation, after three cycles of his five-days-a-month program, as you can see below and at 2:33 in my video

    One hundred men and women were randomized to consume his fasting-mimicking diet for five consecutive days per month or maintain their regular diet the whole time. As you can see in the graph below and at 2:47 in my video, after three months, the FMD group was down about six pounds compared to the control group, with significant drops in body fat and waist circumference, accompanied by a drop in blood pressure. 

    Those who were the worst off accrued the most dramatic benefits, as seen in the graph below and at 3:04 in my video. What’s even wilder is that three further months after completion, some of the benefits appeared to persist, suggesting the effects “may last for several months.” It’s unclear, though, if those randomized to the FMD group used it as an opportunity to make positive lifestyle changes that helped maintain some of the weight loss. 


    Dr. Longo created a company to market his meal plan commercially, but, to his credit, says “he does not receive a salary or a consulting fee from the company…and will donate 100% of his shares to charity.” The whole diet appears to be mostly dehydrated soup mixes, herbal teas like hibiscus and chamomile, kale chips, nut-based energy bars, an algae-based DHA supplement, and a multivitamin dusted with vegetable powder. Why spend 50 dollars a day on a few processed snacks when you could instead eat a few hundred calories a day of real vegetables? 
     
    How interesting was that? All-you-can-eat above-ground vegetables for five days would have the same low amount of protein, sugars, and calories with zero animal protein or animal fat. But we’ll probably never know if it works as well, better, or worse because it’s hard to imagine such a study ever getting done without the financial incentive. 

    To learn more about IGF-1, see my video Flashback Friday: Animal Protein Compared to Cigarette Smoking.
     
    In this series on fasting, I’ve covered several topics, including the basics of calories and weight loss, water-only fasting, and the types of alternate-day fasting, see them all in the related videos below. 
     
    I close out the series with videos on time-restricted eating: Time-Restricted Eating Put to the Test and The Benefits of Early Time-Restricted Eating
     
    If you want all of the videos in one place, I’ve done three webinars on fasting—Intermittent Fasting, Fasting for Disease Reversal, and Fasting and Cancer—and they’re all available for download now. 

    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

    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. 

    Michael Greger M.D. FACLM

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  • The Safety of Keto Diets  | NutritionFacts.org

    The Safety of Keto Diets  | NutritionFacts.org

    What are the effects of ketogenic diets on nutrient sufficiency, gut flora, and heart disease risk? 

    Given the decades of experience using ketogenic diets to treat certain cases of pediatric epilepsy, a body of safety data has accumulated. Nutrient deficiencies would seem to be the obvious issue. Inadequate intake of 17 micronutrients, vitamins, and minerals has been documented in those on strict ketogenic diets, as you can see in the graph below and at 0:14 in my video Are Keto Diets Safe?

    Dieting is a particularly important time to make sure you’re meeting all of your essential nutrient requirements, since you may be taking in less food. Ketogenic diets tend to be so nutritionally vacuous that one assessment estimated that you’d have to eat more than 37,000 calories a day to get a sufficient daily intake of all essential vitamins and minerals, as you can see in the graph below and at 0:39 in my video


    That is one of the advantages of more plant-based approaches. As the editor-in-chief of the Journal of the American Dietetic Association put it, “What could be more nutrient-dense than a vegetarian diet?” Choosing a healthy diet may be easier than eating more than 37,000 daily calories, which is like putting 50 sticks of butter in your morning coffee. 
     
    We aren’t just talking about not reaching your daily allowances either. Children have gotten scurvy on ketogenic diets, and some have even died from selenium deficiency, which can cause sudden cardiac death. The vitamin and mineral deficiencies can be solved with supplements, but what about the paucity of prebiotics, the dozens of types of fiber, and resistant starches found concentrated in whole grains and beans that you’d miss out on? 
     
    Not surprisingly, constipation is very common on keto diets. As I’ve reviewed before, starving our microbial self of prebiotics can have a whole array of negative consequences. Ketogenic diets have been shown to “reduce the species richness and diversity of intestinal microbiota,” our gut flora. Microbiome changes can be detected within 24 hours of switching to a high-fat, low-fiber diet. A lack of fiber starves our good gut bacteria. We used to think that dietary fat itself was nearly all absorbed in the small intestine, but based on studies using radioactive tracers, we now know that about 7 percent of the saturated fat in a fat-rich meal can make it down to the colon. This may result in “detrimental changes” in our gut microbiome, as well as weight gain, increased leaky gut, and pro-inflammatory changes. For example, there may be a drop in beneficial Bifidobacteria and a decrease in overall short-chain fatty acid production, both of which would be expected to increase the risk of gastrointestinal disorders. 
     
    Striking at the heart of the matter, what might all of that saturated fat be doing to our heart? If you look at low-carbohydrate diets and all-cause mortality, those who eat lower-carb diets suffer “a significantly higher risk of all-cause mortality,” meaning they live, on average, significantly shorter lives. However, from a heart-disease perspective, it matters if it’s animal fat or plant fat. Based on the famous Harvard cohorts, eating more of an animal-based, low-carb diet was associated with higher death rates from cardiovascular disease and a 50 percent higher risk of dying from a heart attack or stroke, but no such association was found for lower-carb diets based on plant sources.  
     
    And it wasn’t just Harvard. Other researchers have also found that “low-carbohydrate dietary patterns favoring animal-derived protein and fat sources, from sources such as lamb, beef, pork, and chicken, were associated with higher mortality, whereas those that favored plant-derived protein and fat intake, from sources such as vegetables, nuts, peanut butter, and whole-grain bread, were associated with lower mortality…” 
     
    Cholesterol production in the body is directly correlated to body weight, as you can see in the graph below and at 3:50 in my video

    Every pound of weight loss by nearly any means is associated with about a one-point drop in cholesterol levels in the blood. But if we put people on very-low-carb ketogenic diets, the beneficial effect on LDL bad cholesterol is blunted or even completely neutralized. Counterbalancing changes in LDL or HDL (what we used to think of as good cholesterol) are not considered sufficient to offset this risk. You don’t have to wait until cholesterol builds up in your arteries to have adverse effects either; within three hours of eating a meal high in saturated fat, you can see a significant impairment of artery function. Even with a dozen pounds of weight loss, artery function worsens on a ketogenic diet instead of getting better, which appears to be the case with low-carb diets in general.  

    For more on keto diets, check out my video series here

    And, to learn more about your microbiome, see the related videos below.

    Michael Greger M.D. FACLM

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  • Diabetes Associations Recognize Plant-Based Diets  | NutritionFacts.org

    Diabetes Associations Recognize Plant-Based Diets  | NutritionFacts.org

    Plant-based diets are the single most important—yet underutilized—opportunity to reverse the pending obesity and diabetes-induced epidemic of disease and death. 

    Dr. Kim Williams, immediate past president of the American College of Cardiology, started out an editorial on plant-based diets with the classic Schopenhauer quote: “All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident.” In 2013, plant-based diets for diabetes were in the “ridiculed” stage in the official endocrinology practice guidelines and placed in the “Fad Diets” section. The guidelines acknowledged that strictly plant-based diets “have been shown to reduce the risk for T2DM [type 2 diabetes] and improve management of T2DM” better than the American Diabetes Association recommendations, then inexplicably went on to say that it “does not support the use of one type of diet over another” with respect to diabetes or in general. “The best approach for a healthy lifestyle is simply the ‘amelioration of unhealthy choices’”—whatever that means. 

    But, by 2015, the clinical practice guidelines from the same professional associations explicitly endorsed a plant-based diet as its general recommendation for diabetic patients. The times they are a-changin’! 

    As I discuss in my video Plant-Based Diets Recognized by Diabetes Associations, the American Diabetes Association itself is also now on board, listing plant-based eating as one of the dietary patterns acceptable for the management of the condition. The Canadian Diabetes Association, however, has really taken the lead. “Type 2 diabetes mellitus is considered one of the fastest growing diseases in Canada, representing a serious public health concern,” so it isn’t messing around and recommends plant-based diets for disease management “because of their potential to improve body weight and A1C [blood sugar control], LDL-cholesterol, total cholesterol and non-HDL-cholesterol levels, in addition to reducing the need for diabetes medications.” The Canadian Diabetes Association uses the Kaiser Permanente definition for that eating pattern: “a regimen that encourages whole, plant-based foods and discourages meats, dairy products and eggs, as well as all refined and processed foods,” that is, junk. 

    It recommends that diabetes education centers in Canada “improve patients’ perceptions of PBDs [plant-based diets] by developing PBD-focused educational and support as well as providing individualized counseling sessions addressing barriers to change.” The biggest obstacle identified to eating plant-based was ignorance. Nearly nine out of ten patients interviewed “had not heard of using a plant-based diet to treat or manage T2DM.” Why is that? “Patient awareness of (and interest in) the benefits of a plant-based diet for the management of diabetes…may be “influenced by the perception of diabetes educators and clinicians.” Indeed, most of the staff were aware of the benefits of plant-based eating for treating diabetes, yet only about one in three were recommending it to their patients.  

    Why? One of the common reasons given was they didn’t think their patients would eat plant-based, so they didn’t even bring it up, but “[t]his notion is contrary to the patient survey results that almost two-thirds of patients were willing” to at least give it a try. The researchers cite the PCRM Geico studies I’ve covered in other videos, in which strictly plant-based diets were “well accepted with over 95% adherence rate,” presumably because the study participants just felt so much better, reporting “increased energy level, better digestion, better sleep, and increased satisfaction when compared with the control group.” 

    A number of staff members also expressed they were unclear about the supportive scientific evidence as their second reason for not recommending this diet, but it’s been shown to be more effective than an American Diabetes Association–recommended diet at reducing the use of diabetes medications, long-term blood sugar control, and cholesterol. It’s therefore possible that the diabetes educators were simply behind the times, as there is “a lag-time” in the dissemination of new scientific findings from the literature to the clinician and finally to the patient. Speeding up this process is one of the reasons I started NutritionFacts.org. 

    As Dr. Williams put it, “the ‘truth’ (i.e., evidence) for the benefits of plant-based nutrition continues to mount. This now includes lower rates of stroke, hypertension, diabetes mellitus, obesity, myocardial infarction, and mortality [heart attacks and cardiac death], as well as many non-cardiac issues that affect our patients in cardiology, ranging from cancer to a variety of inflammatory conditions.” We’ve got the science. The bigger challenge is overcoming the “inertia, culture, habit, and widespread marketing of unhealthy foods.” He concludes, “Reading the existing literature and evaluating the impact of plant-based nutrition, it clearly represents the single most important yet underutilized opportunity to reverse the pending obesity and diabetes-induced epidemic of morbidity and mortality,” disease and death. 

    I highlighted the PCRM Geico studies in my videos Slimming the Gecko and Plant-Based Workplace Intervention. 

    Aren’t plant-based diets high in carbs? Get the “skinny” by checking out my video Flashback Friday: Benefits of a Macrobiotic Diet for Diabetes. 

    To learn more about diet’s effect on type 2 diabetes, see the related videos below. 

    Michael Greger M.D. FACLM

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