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Tag: cardiovascular disease

  • Testing for Vitamin B12 Deficiency  | NutritionFacts.org

    Testing for Vitamin B12 Deficiency  | NutritionFacts.org

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    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. 

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    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

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    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: 

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    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

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    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:

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    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

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    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.

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    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

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    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. 

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    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

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    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. 

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    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

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    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.

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    Michael Greger M.D. FACLM

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  • The Stroke Risk of Vegetarians  | NutritionFacts.org

    The Stroke Risk of Vegetarians  | NutritionFacts.org

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    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.

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    Michael Greger M.D. FACLM

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

    Eating to Lower Lp(a)  | NutritionFacts.org

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    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. 

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    Michael Greger M.D. FACLM

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  • How to Treat High Lp(a), an Atherosclerosis Risk Factor  | NutritionFacts.org

    How to Treat High Lp(a), an Atherosclerosis Risk Factor  | NutritionFacts.org

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    What could help explain severe coronary disease in someone with a healthy lifestyle who is considered to be at low cardiovascular disease risk? A young man ended up in the ER after a heart attack and was ultimately found to have severe coronary artery disease. Given his age, blood pressure, and cholesterol, his ten-year risk of a heart attack should have only been about 2 percent, but he had a high lipoprotein(a), also known as Lp(a). In fact, it was markedly high at 80 mg/dL, which may help explain it. You can see the same in women: a 27-year-old with a heart attack with a high Lp(a). What is Lp(a), and what can we do about it? 

    As I discuss in my video Treating High Lp(a): A Risk Factor for Atherosclerosis, Lp(a) is an “underestimated cardiovascular risk factor.” It causes coronary artery disease, heart attacks, strokes, peripheral arterial disease, calcified aortic valve disease, and heart failure. And these can occur in people who don’t even have high cholesterol—because Lp(a) is cholesterol, as you can see below and at 1:15 in my video. It’s an LDL cholesterol molecule linked to another protein, which, like LDL, transfers cholesterol into the lining of our arteries, contributing to the inflammation in atherosclerotic plaques. But “this increased risk caused by Lp(a) has not yet gained recognition by practicing physicians.” 

    “The main reason for the limited clinical use of Lp(a) is the lack of effective and specific therapies to lower Lp(a) plasma levels.” Because “Lp(a) concentrations are approximately 90% genetically determined,” the conventional thinking has been you’re just kind of born with higher or lower levels and there isn’t much you can do about it. Even if that were the case, though, you might still want to know about it. If it were high, for instance, that would be all the more reason to make sure all the other risk factors that you do have more control over are as good as possible. It may help you quit smoking, for example, and motivate you to do everything you can to lower your LDL cholesterol as much as possible.  

    Lp(a) levels in the blood can vary a thousand-fold between individuals, “from less than 0.1 mg/dL to as high as 387 mg/dL.” You can see a graph of the odds of heart disease at different levels in the graph below and at 2:20 in my video. Less than 20 mg/dL is probably optimal, with greater than 30 to 50 mg/dL considered to be elevated. Even when the more conservative threshold of greater than 50 mg/dL is used, that describes about 10 to 30 percent of the global population, an estimated 1.4 billion people. So, if we’re in the one in five people with elevated levels, what can we do about it? 

    The way we know that Lp(a) causes atherosclerosis is that we can put it to the ultimate test. There is something called apheresis, which is essentially like a dialysis machine where they can take out your blood, wash out some of the Lp(a), and give your blood back to you. And when you do that, you can reverse the progression of the disease. As you can see in the graph below and at 3:06 in my video, atherosclerosis continues to get worse in the control group, but it gets better in the apheresis group. This is great for proving the role of Lp(a), but it has limited clinical application, given the “cost, limited access to centers, and the time commitment required for biweekly sessions of 2 to 4 h each.” 

    It causes a big drop in blood levels, but they quickly creep back up, so you have to keep going in, as you can see in the graph below and at 3:26 in my video, costing more than $50,000 a year. 

    There has to be a better way. We’ll explore the role diet can play, next.  

    I’ve been wanting to do videos about Lp(a), but there just wasn’t much we could do about it until now. So, how do we lower Lp(a) with diet? Stay tuned for the exciting conclusion in my next video.

    What can we do to minimize heart disease risk? My video How Not to Die from Heart Disease is a good starting point. 

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    Michael Greger M.D. FACLM

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  • What Should We Eat?  | NutritionFacts.org

    What Should We Eat?  | NutritionFacts.org

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    Here is a review of reviews on the health effects of animal foods versus plant foods.

    Instead of looking only at individual studies or individual reviews of studies, what if you looked at a review of reviews? In my last video, I covered beverages. As you can see below and at 0:20 in my video Friday Favorites: What Are the Best Foods?, the majority of reviews found some effects either way, finding at least some benefits to tea, coffee, wine, and milk, but not for sweetened beverages, such as soda. As I explored in depth, this approach isn’t perfect. It doesn’t take into account such issues as conflicts of interest and industry funding of studies, but it can offer an interesting bird’s-eye view of what’s out in the medical literature. So, what did the data show for food groups? 

    You’ll note the first thing the authors did was divide everything into plant-based foods or animal-based foods. For the broadest takeaway, we can look at the totals. The vast majority of reviews on whole plant foods show protective or, at the very least, neutral effects, whereas most reviews of animal-based foods identified deleterious health effects or, at best, neutral effects, as you can see at 1:14 in my video. 

    Let’s break these down. As you can see in the graph below and at 1:23, the plant foods consistently rate uniformly well, reflecting the total, but the animal foods vary considerably. If it weren’t for dairy and fish, the total for animal foods would swing almost entirely neutral or negative. 

    I talked about the effects of funding by the dairy industry in my last blog, as well as substitution effects. For instance, those who drink milk may be less likely to drink soda, a beverage even more universally condemned than dairy, so the protective effects may be relative. They may arise not necessarily from what is being consumed, but rather from what is being avoided. This may best explain the fish findings. After all, the prototypical choice is between chicken and fish, not chicken and chickpeas.

    Not a single review found a single protective effect of poultry consumption. Even the soda industry could come up with 14 percent protective effects! But, despite all of the funding from the National Chicken Council and the American Egg Board, chicken, and eggs got big fat goose eggs, as you can see below and at 2:20 in my video. 

    Also, like the calcium in dairy, there are healthful components of fish, such as the long-chain omega-3 fatty acids. Not for heart health, though. In “the most extensive systematic assessment of effects of omega-3 fats on cardiovascular health to date,” increasing intake of fish oil fats had little or no effect on cardiovascular health. If anything, it was the plant-based omega-3s found in flaxseeds and walnuts that were protective. The long-chain omega-3s are important for brain health. Thankfully, just like there are best-of-both-worlds non-dairy sources of calcium, there are pollutant-free sources of the long-chain omega-3s, EPA, and DHA, as well.

    The bottom line, as you can see below and at 3:04 in my video, is that when it comes to diet-related diseases, such as obesity, type 2 diabetes, mental health, bone health, cardiovascular disease, and cancers, even if you lump together all the animal foods, ignore any industry-funding effects, and just take the existing body of evidence at face value, nine out of ten study compilations show that whole plant foods are, in the very least, not bad.

    However, about eight out of ten of the reviews on animal products show them to be not good, as shown in the graph below and at 3:24 in my video.

    This reminds me of my Flashback Friday: What Are the Healthiest Foods? video, which you may find to be helpful for some broad takeaways.

    If you missed my previous video, check out Friday Favorites: What Are the Best Beverages?.

    The omega-3s video I mentioned is Should Vegans Take DHA to Preserve Brain Function?.

    For more on eggs, see here.

    On fish, go here.

    And, for poultry, see related posts below. 

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    Michael Greger M.D. FACLM

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  • What Should We Drink?  | NutritionFacts.org

    What Should We Drink?  | NutritionFacts.org

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    Here is a review of reviews on the health effects of tea, coffee, milk, wine, and soda.

    If you’ve watched my videos or read my books, you’ve heard me say, time and again, the best available balance of evidence. What does that mean? When making decisions as life-or-death important as what to feed ourselves and our families, it matters less what a single study says, but rather what the totality of peer-reviewed science has to say.

    Individual studies can lead to headlines like “Study Finds No Link Between Secondhand Smoke and Cancer,” but to know if there is a link between secondhand smoke and lung cancer, it would be better to look at a review or meta-analysis that compiles multiple studies. The problem is that some reviews say one thing—for instance, “breathing other people’s tobacco smoke is a cause of lung cancer”—and other reviews say another—such as, the effects of secondhand smoke are insignificant and further such talk may “foster irrational fears.” And, while we’re at it, you can indulge in “active smoking of some 4-5 cigarettes per day” without really worrying about it, so light up!

    Why do review articles on the health effects of secondhand smoke reach such different conclusions? As you can imagine, about 90 percent of reviews written by researchers affiliated with the tobacco industry said it was not harmful, whereas you get the opposite number with independent reviews, as you can see below and at 1:18 in my video Friday Favorites: What Are the Best Beverages?. Reviews written by the tobacco industry–affiliated researchers had 88 times the odds of concluding that secondhand smoke was harmless. It was all part of “a deliberate strategy to use scientific consultants to discredit the science…” In other words, “the strategic and long run antidote to the passive smoking issue…is developing and widely publicizing clear-cut, credible, medical evidence that passive smoking [secondhand smoke] is not harmful to the non-smoker’s health.”

    Can’t we just stick to the independent reviews? The problem is that industry-funded researchers have all sorts of sneaky ways to get out of declaring conflicts of interest, so it can be hard to follow the money. For instance, it was found that “77% failed to disclose the sources of funding” for their research. But, even without knowing who funded what, the majority of reviews still concluded that secondhand smoke was harmful. So, just as a single study may not be as helpful as looking at a compilation of studies on a topic, a single review may not be as useful as a compilation of reviews. In that case, looking at a review of reviews can give us a better sense of where the best available balance of evidence may lie. When it comes to secondhand smoke, it’s probably best not to inhale, as you can see in the graph below and at 2:30 in my video. 

    Wouldn’t it be cool if there were reviews of reviews for different foods and drinks? Voila! Enter “Associations Between Food and Beverage Groups and Major Diet-Related Chronic Diseases: An Exhaustive Review of Pooled/Meta-Analyses and Systematic Reviews.” Let’s start with the drinks. As you can see below and at 2:51 in my video, the findings were classified into three categories: protective, neutral, or deleterious.

    First up: tea versus coffee. As you can see in the graph below and at 2:58, most reviews found both beverages to be protective for whichever condition they were studying, but you can see how this supports my recommendation for tea over coffee. Every cup of coffee is a lost opportunity to drink a cup of green tea, which is even healthier. 

    It’s no surprise that soda sinks to the bottom, as you can see below and at 3:20 in my video, but 14 percent of reviews mentioned the protective effects of drinking soda. What?! Well, most were references to papers like “High Intake of Added Sugar Among Norwegian Children and Adolescents,” a cross-sectional study that found that eighth-grade girls who drank more soda were thinner than girls who drank less. Okay, but that was just a snapshot in time. What do you think is more likely? That the heavier girls were heavier because they drank less soda, or that they drank less sugary soda because they were heavier? Soda abstention may therefore be a consequence of obesity, rather than a cause, yet it gets marked down as having a protective association. 

    Study design flaws may also account for wine numbers, as seen below and at 4:07 in my video. This review of reviews was published in 2014, before the revolution in our understanding of “alcohol’s evaporating health benefits,” suggesting that the “presumed health benefits from ‘moderate’ alcohol use [may have] finally collapsed”—thanks in part to a systematic error of misclassifying former drinkers as if they were lifelong abstainers, as I revealed in a deep dive in a video series on the subject.  

    Sometimes there are unexplainable associations. For example, one of the soft drink studies found that increased soda consumption was associated with a lower risk of certain types of esophageal cancers. Don’t tell me. Was the study funded by Coca-Cola? Indeed. Does that help explain the positive milk studies, as you can see in the graph below and at 5:02 in my video? Were they all just funded by the National Dairy Council? 

    As shown below and at 5:06, even more conflicts of interest have been found among milk studies than soda studies, with industry-funded studies of all such beverages “approximately four to eight times more likely to be favorable to the financial interests of the [study] sponsors than articles without industry-related funding.”

    Funding bias aside, though, there could be legitimate reasons for the protective effects associated with milk consumption. After all, those who drink more milk may drink less soda, which is even worse, so they may come out ahead. It may be more than just relative benefits, though. The soda-cancer link seems a little tenuous and not just because of the study’s financial connection to The Coca-Cola Company. It’s hard to imagine a biologically plausible mechanism, whereas even something as universally condemned as tobacco isn’t universally bad. As I’ve explored before, more than 50 studies have consistently found a protective association between nicotine and Parkinson’s disease. Even secondhand smoke may be protective. Of course, you’d still want to avoid it. Passive secondhand smoke may decrease the risk of Parkinson’s, but it increases the risk of stroke, an even deadlier brain disease, not to mention lung cancer and heart disease, which has killed off millions of Americans since the first Surgeon General’s report was released, as you can see below and at 6:20 in my video. 

    Thankfully, by eating certain vegetables, we may be able to get some of the benefits without the risks, and the same may be true of dairy. As I’ve described before, the consumption of milk is associated with an increased risk of prostate cancer, leading to recommendations suggesting that men may want to cut down or minimize their intake, but milk consumption is also associated with decreased colorectal cancer risk. This appears to be a calcium effect. Thankfully, we may be able to get the best of both worlds by eating high-calcium plant foods, such as greens and beans.  

    What does our review-of-reviews study conclude about such plant-based foods, in comparison to animal-based foods? We’ll find out next.

    Stay tuned for the exhaustive review of meta-analyses and systematic reviews on major diet-related chronic diseases found for food groups in What Are the Best Foods?.

    The alcohol video I mentioned is Is It Better to Drink a Little Alcohol Than None at All?, and the Parkinson’s video is Pepper’s and Parkinson’s: The Benefits of Smoking Without the Risks. I also mentioned my Dairy and Cancer video. 

    What about diet soda? See related posts below. 

    What’s so bad about alcohol? Check out Can Alcohol Cause Cancer? and Do Any Benefits of Alcohol Outweigh the Risks? for more. 

    I’ve also got tons of milk. Check here.

    My recommendations for the best beverages are water, green tea, and hibiscus herbal tea. Learn more in the related posts below.

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    Michael Greger M.D. FACLM

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

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

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

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

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

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

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

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

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

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

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

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

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

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    Michael Greger M.D. FACLM

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  • A King’s Breakfast, a Prince’s Lunch, and a Pauper’s Dinner  | NutritionFacts.org

    A King’s Breakfast, a Prince’s Lunch, and a Pauper’s Dinner  | NutritionFacts.org

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    Harness the power of your circadian rhythms for weight loss by making breakfast or lunch your main meal of the day.

    In my last chronobiology video, we learned that calories eaten at breakfast are significantly less fattening than the same number of calories eaten at dinner, as you can see at 0:14 in my video Breakfast Like a King, Lunch Like a Prince, Dinner Like a Pauper, but who eats just one meal a day? 

    What about simply shifting our daily distribution of calories to earlier in the day? Israeli researchers randomized overweight and obese women into one of two isocaloric groups, meaning each group was given the same number of total calories. One group got a 700-calorie breakfast, a 500-calorie lunch, and a 200-calorie dinner, and the other group got the opposite—200 calories for breakfast, 500 for lunch, and 700 for dinner. Since all of the study participants were eating the same number of calories overall, the king-prince-pauper group should have lost the same amount of weight as the pauper-prince-king group, right? But, no. As you can see in the graph below and at 1:01 in my video, the bigger breakfast group lost more than twice as much weight, in addition to slimming about an extra two inches off their waistline. By the end of the 12-week study, the king-prince-pauper group lost 11 more pounds than the bigger dinner group, dropping 19 pounds compared to only 8 pounds lost by the pauper-prince-king group—despite eating the same number of calories. That’s the power of chronobiology, the power of our circadian rhythm. 

    What was the caloric distribution of the king-prince-pauper group getting 700 calories at breakfast, 500 at lunch, and 200 at dinner? They got 50 percent of calories at breakfast, 36 percent at lunch, and only 14 percent of calories at dinner, which is pretty skewed. What about 20 percent for dinner instead? A 50% – 30% – 20% spread, compared to 20% – 30% – 50%?

    Again, the bigger breakfast group experienced “dramatically increased” weight loss, a difference of about nine pounds in eight weeks with no significant difference in overall caloric intake or physical activity between the groups, as shown in the graph below and at 1:57 in my video. 

    Instead of 80 percent of calories consumed at breakfast and lunch, what about 70 percent compared to 55 percent? Researchers randomized overweight “homemakers” to eat 70 percent of their calories at breakfast, a morning snack, and lunch, leaving 30 percent for an afternoon snack and dinner, or a more balanced 55 percent from the time they woke up through lunch. In both cases, only a minority of calories were eaten for dinner, as you can see below, and at 2:25 in my video. Was there any difference between eating 70 percent of calories through lunch versus only 55 percent? Yes, those eating more calories earlier in the day had significantly more weight loss and slimming. 

    Concluded the researchers: “Stories about food and nutrition are in the news on an almost daily basis, but information can sometimes be confusing and contradictory. Clear messages should be proposed to reach the greatest number of people. One clear communication from physicians could be ‘If you want to lose weight, eat more in the morning than in the evening.’” 

    Even just telling people to eat their main meal at lunch rather than dinner may help. Despite comparable caloric intakes, participants in a weight-loss program randomized to get advice to make lunch their main meal beat out those who instead were told to make dinner their main meal.

    The proverb “Eat breakfast like a king, lunch like a prince, and dinner like a pauper” evidently has another variant: “Eat breakfast yourself, share lunch with a friend, and give dinner away to your enemy.” I wouldn’t go that far, but there does appear to be a metabolic benefit to frontloading the bulk of your calories earlier in the day.

    The evidence isn’t completely consistent, though. A review of dietary pattern studies questioned whether reducing evening intake would facilitate weight loss, citing a study that showed the evening-weighted group did better than the heavy-morning-meal group. Perhaps that was because the morning meal group was given “chocolate, cookies, cake, ice cream, chocolate mousse or donuts” for breakfast. So, chronobiology can be trumped by a junk-food methodology. Overall, the what is still more important than the when. Caloric timing may be used to accelerate weight loss, but it doesn’t substitute for a healthy diet. When he said there was a time for every purpose under heaven, Ecclesiastes probably wasn’t talking about donuts.

    When I heard about this, what I wanted to know was how. Why does our body store less food as fat in the morning? I explore the mechanism in my next video, Eat More Calories in the Morning Than the Evening.

    This is the fifth video in an 11-part series on chronobiology. If you missed the first four, check out the related posts below. 

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    Michael Greger M.D. FACLM

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  • Lose Weight by Eating More in the Morning  | NutritionFacts.org

    Lose Weight by Eating More in the Morning  | NutritionFacts.org

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    A calorie is not a calorie. It isn’t only what you eat, but when you eat.

    Mice are nocturnal creatures. They eat during the night and sleep during the day. However, if you only feed mice during the day, they gain more weight than if they were fed a similar amount of calories at night. Same food and about the same amount of food, but different weight outcomes, as you can see in the graph below and at 0:18 in my video Eat More Calories in the Morning to Lose Weight, suggesting that eating at the “wrong” time may lead to disproportionate weight gain. In humans, the wrong time would presumably mean eating at night. 

    Recommendations for weight management often include advice to limit nighttime food consumption, but this was largely anecdotal until it was first studied experimentally in 2013. Researchers instructed a group of young men not to eat after 7:00 pm for two weeks. Compared to a control period during which they continued their regular habits, they ended up about two pounds lighter after the night-eating restriction. This is not surprising, given that dietary records show the study participants inadvertently ate fewer calories during that time. To see if timing has metabolic effects beyond just foreclosing eating opportunities, you’d have to force people to eat the same amount of the same food, but at different times of the day. The U.S. Army stepped forward to carry out just such an investigation.

    In their first set of experiments, Army researchers had people eat a single meal a day either as breakfast or dinner. The results clearly showed the breakfast group lost more weight, as you can see in the graph below and at 1:35 in my video. When study participants ate only once a day at dinner, their weight didn’t change much, but when they ate once a day at breakfast, they lost about two pounds a week. 

    Similar to the night-eating restriction study, this is to be expected, given that people tend to be hungrier in the evening. Think about it. If you went nine hours without eating during the day, you’d be famished, but people go nine hours without eating overnight all the time and don’t wake up ravenous. There is a natural circadian rhythm to hunger that peaks around 8:00 pm and drops to its lowest level around 8:00 am, as you can see in the graph below and at 2:09 in my video. That may be why breakfast is typically the smallest meal of the day. 

    The circadian rhythm of our appetite isn’t just behavioral, but biological, too. It’s not just that we’re hungrier in the evening because we’ve been running around all day. If you stayed up all night and slept all day, you’d still be hungriest when you woke up that evening. To untangle the factors, scientists used what’s called a “forced desynchrony” protocol. Study participants stayed in a room without windows in constant, unchanging, dim light and slept in staggered 20-hour cycles to totally scramble them up. This went on for more than a week, so the subjects ended up eating and sleeping at different times throughout all phases of the day. Then, the researchers could see if cyclical phenomena are truly based on internal clocks or just a consequence of what you happen to be doing at the time.  

    For instance, there is a daily swing in our core body temperature, blood pressure, hormone production, digestion, immune activity, and almost everything else, but let’s use temperature as an example. As you can see in the graph below and at 3:21 in my video, our body temperature usually bottoms out around 4:00 am, dropping from 98.6°F (37°C) down to more like 97.6°F (36.4°C). Is this just because our body cools down as we sleep? No. By keeping people awake and busy for 24 hours straight, it can be shown experimentally that it happens at about the same time no matter what. It’s part of our circadian rhythm, just like our appetite. It makes sense, then, if you are only eating one meal per day and want to lose weight, you’d want to eat in the morning when your hunger hormones are at their lowest level. 

    Sounds reasonable, but it starts to get weird.

    The Army scientists repeated the experiment, but this time, they had the participants eat exactly 2,000 calories either as breakfast or as dinner, taking appetite out of the picture. The subjects weren’t allowed to exercise either. Same number of calories, so the same change in weight, right? No. As you can see in the graph below and at 4:18 in my video, the breakfast-only group still lost about two pounds a week compared to the dinner-only group. Two pounds of weight loss eating the same number of calories. That’s why this concept of chronobiology, meal timing—when to eat—is so important. 

    Isn’t that wild? Two pounds of weight loss a week eating the same number of calories! That was a pretty extreme study, though. What about just shifting a greater percentage of calories to earlier in the day? That’s the subject of my next video: Breakfast Like a King, Lunch Like a Prince, Dinner Like a Pauper. First, let’s take a break from chronobiology to look at the Benefits of Garlic for Fighting Cancer and the Common Cold. Then, we’ll resume checking other videos in the related posts below.

    If you missed the first three videos in this extended series, also check out related posts below. 

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    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

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    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.

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    Michael Greger M.D. FACLM

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  • The Ozempic Revolution Is Stuck

    The Ozempic Revolution Is Stuck

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    Millions more Americans are now eligible for obesity drugs. But the injections remain maddeningly hard to find.

    Illustration by The Atlantic. Source: Getty.

    The irony undergirding the new wave of obesity drugs is that they initially weren’t created for obesity at all. The weight loss spurred by Ozempic, a diabetes drug in the class of so-called GLP-1 agonists, gave way to Wegovy—the same drug, repackaged for obesity. Zepbound, another medication, soon followed. Now these drugs have a new purpose: heart health.

    On Friday, the FDA approved the use of Wegovy for reducing the risk of heart attack, stroke, and death in adults who are overweight and have cardiovascular disease. The move had been anticipated since the publication of a landmark trial in the fall, which showed the drug’s profound effects on cardiovascular  health. The decision could usher in a new era where GLP-1 drugs become mainstream, opening up access to millions of Americans who previously didn’t qualify for Wegovy.

    Some of the obstacles stopping people from getting the drug may also begin to crumble. Insurance companies commonly deny coverage of Wegovy because obesity is seen as a cosmetic concern rather than a medical one, but that argument may not hold up for cardiovascular disease. “This new FDA indication is HUGE,” Katherine Saunders, an obesity-medicine physician at Weill Cornell Medicine, told me in an email. Wegovy may soon be within reach for many more Americans—that is, if they can find it.

    In practice, Wegovy is maddeningly hard to get hold of. Shortages of injectable semaglutide, the active ingredient in Wegovy and Ozempic, have been ongoing since March 2022; currently, most doses of Wegovy are in limited supply. As the popularity of semaglutide has skyrocketed, demand has completely outstripped the capacity of its manufacturer, Novo Nordisk. The drug comes in injection pens containing a glass vial; “these are not easy products to make,” Lars Fruergaard Jørgensen, the CEO of Novo Nordisk, said in August. In response to the shortages, the company withheld its supply of lower Wegovy doses last year. Because treatment on the medication must begin in low doses, this meant that new patients who wanted to start on Wegovy functionally couldn’t. In January, the company began “more than doubling the amount of the lower-dose strengths” of the drug, a Novo Nordisk spokesperson told me, and it plans to gradually increase overall supply throughout the rest of the year.

    The ongoing shortages have left providers and patients feeling stuck. “It is devastating to prescribe a lifesaving medication for a patient and then find out it’s not covered or we can’t locate supply,” Saunders said. Doctors are scrambling to make do with what’s available. Ivania Rizo, an endocrinologist at Boston Medical Center, told me she has had to turn to older GLP-1 drugs such as Saxenda to “bridge” patients to higher doses of Wegovy, although now that is in shortage too. Patients can spend each day calling pharmacy after pharmacy in search of one with Wegovy in stock, Rizo said. In desperation, some have turned to versions of the drug that are custom-made by compounding pharmacies with little oversight, despite the FDA expressing concerns about them. The shots are supposed to be taken weekly, but others have attempted to stretch their doses beyond that.

    That the new FDA approval could very mainstream obesity drugs may create long-needed pressure to help resolve these shortages. It makes clear that Wegovy is a lifesaving medication not only for people with obesity but also for those with cardiovascular disease—the leading cause of death in the U.S.—putting the impetus on Novo Nordisk to ramp up production. But in the short term, the access issues may persist. “The new approval is very likely to worsen shortages, because the demand for Wegovy will continue to climb—now at an even faster pace,” Saunders said.

    If patients think they’re stuck now, they’re about to feel entrenched. Wegovy is the only obesity drug that has been approved to reduce the risk of heart attacks, but none of its competitors is easily available either. Supplies of certain dosages of Eli Lilly’s Mounjaro, a diabetes drug whose active ingredient is sold for obesity as Zepbound, are limited, and shortages are expected later this year. “We need supply to increase dramatically,” Saunders said. Both Novo Nordisk and Eli Lilly have invested heavily in expanding production capacity, but some of the new plants won’t open until 2029.

    For all of its advantages, the FDA approval has a sobering effect on the unrelenting hype around GLP-1s. So much of the excitement around obesity drugs has focused on the future, as dozens of pharmaceutical companies develop more powerful drugs, and commentators imagine a world without obesity. In the process, the issues of the present have gone overlooked. More drugs won’t make much of a difference if the drugs themselves are out of reach.

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    Yasmin Tayag

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  • Fighting Inflammation with Flaxseeds  | NutritionFacts.org

    Fighting Inflammation with Flaxseeds  | NutritionFacts.org

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    Elevated levels of pro-inflammatory, aging-associated oxylipins can be normalized by eating ground flaxseed. 

    I previously explored the “Potent Antihypertensive Effect of Dietary Flaxseed in Hypertensive Patients” study in my video Flaxseeds for Hypertension. That was a double-blind, randomized, placebo-controlled trial where researchers disguised ground flaxseed in baked goods versus flax-free placebo muffins and saw an extraordinary drop in high blood pressure. As you can imagine, the flaxseed industry was overjoyed, praising the “impressive” findings, as was I. After all, high blood pressure is “the single largest risk factor” for death in the world. Yes, we give people medications, lots and lots of medications, but most people don’t take them. Nine out of ten people take less than 80 percent of their prescribed blood pressure pills. 
     
    It’s not difficult to understand why. “Patients are asked to follow an inconvenient and potentially costly regimen, which will likely have a detrimental effect on health-related quality of life, to treat a mostly asymptomatic condition that commonly does not cause problems for many years.” So, they may feel worse instead of better, due to the side effects. Then, some think the answer is to give them even more drugs to counteract the effects of the first drugs, like giving men Viagra to counteract the erectile dysfunction caused by their blood pressure pills. 
     
    How about using a dietary strategy instead, especially if it can be just as effective? And, indeed, the drop in blood pressure the researchers saw in the flaxseed study “was greater than the average decrease observed with the standard dose of anti-hypertensive medications.” Flaxseeds are cheaper, too, compared to even single medications, and most patients are on multiple drugs. Plus, flaxseeds have good side effects beyond their anti-hypertensive actions. Taking tablespoons of flaxseed a day is a lot of fiber for people living off of cheeseburgers and milkshakes their whole lives, and your gut bacteria may need a little time to adjust to the new bounty. So, those who start with low-fiber diets may want to take it a little slow with the flaxseeds at first. 
     
    Not all studies have shown significant blood pressure–lowering effects, though. There have been more than a dozen trials by now, involving more than a thousand subjects. And, yes, when you put them all together, overall, there were “significant reductions in both SBP and DBP”—systolic blood pressure (the upper number) and diastolic blood pressure (the lower number)—“following supplementation with various flaxseed products.” But none was as dramatic as what the researchers had found in that six-month trial. The longer trials tended to show better results, and some of the trials just used flaxseed oil or some kind of flaxseed extract. We think this is because the whole is greater than the sum of its parts. “Each of the components of interest within flaxseed, ALA, lignans, fiber, and peptides”—the omega-3s, the cancer-fighting lignans, all the soluble fiber, and the plant proteins, for instance—“all contribute towards BP reduction.” Okay, but how? Why? What is the mechanism? 
     
    Some common blood-pressure medications like Norvasc or Procardia work in part by reducing the ability of the heart to contract or by slowing down the heart. So, might it be that’s how flaxseeds work, too? But, no. In my video Benefits of Flaxseeds for Inflammation, I profile the “Dietary Flaxseed Reduces Central Aortic Blood Pressure Without Cardiac Involvement but Through Changes in Plasma Oxylipins” study. What are oxylipins? 
     
    “Oxylipins are a group of fatty acid metabolites” involved in inflammation and, as a result, have been implicated in many pro-inflammatory conditions, including aging and cardiovascular disease. “The best-characterized oxylipins about cardiovascular disease are derived from the w-6 fatty acid arachidonic acid,” a long-chain omega-6 fatty acid. These are found preformed in animal products, particularly chicken and eggs, and can be made inside the body from junky oils rich in omega-6, such as cottonseed oil, as noted below and at 3:49 in my video. But, as this study is titled, “Elevated levels of pro-inflammatory oxylipins in older subjects are normalized by flaxseed consumption.” 

    That’s how we think flaxseed consumption reduces blood pressure in patients with hypertension: by inhibiting the enzyme that makes these pro-inflammatory oxylipins. I’ll spare you from acronym overload, but eating flaxseeds inhibits the activity of the enzyme that makes these pro-inflammatory oxylipins, called leukotoxin diols, which in turn may lower blood pressure. “Identifying the biological mechanism adds confidence to the antihypertensive actions of dietary flaxseed,” but that’s not all oxylipins do. Oxylipins may also play a role in the aging process. However, we may be able to “beneficially disrupt these biological changes associated with inflammation and aging” with a nutritional intervention like flaxseed. Older adults around age 50 have higher levels of this arachidonic acid–derived oxylipin compared to younger adults around age 20, as you can see in the graph below and at 4:56 in my video. “These elevated concentrations of pro-inflammatory oxylipins in the older age group…may…explain the higher levels of inflammation in older versus younger individuals.” As we get older, we’re more likely to be stricken with inflammatory conditions like arthritis. So, this “elevation of pro-inflammatory oxylipins…may predispose individuals to chronic disease conditions.”

    What if you took those older adults and gave them muffins, like the ones with ground flaxseed? That’s just what a group of researchers did. Four weeks later, the subjects’ levels dropped down to like 20-year-olds’ levels, as seen in the graph below and at 5:32 in my video, “demonstrating that a potential therapeutic strategy to correct the deleterious pro-inflammatory oxylipin profile is via a dietary supplementation with flaxseed.”

    What about flax and cancer? See the related posts below. 

    I also have a video on diabetes: Flaxseeds vs. Diabetes. 

    If you’re interested in weight loss, see Benefits of Flaxseed Meal for Weight Loss. 

    What about the cyanide content of flax? I answered that in Friday Favorites: How Well Does Cooking Destroy the Cyanide in Flaxseeds and Should We Be Concerned About It?.

    What else can help fight inflammation? Check out in related posts below.

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    Michael Greger M.D. FACLM

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  • How Safe Is Alternate-Day Intermittent Fasting?  | NutritionFacts.org

    How Safe Is Alternate-Day Intermittent Fasting?  | NutritionFacts.org

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    Eating every other day can raise your cholesterol. 
     
    Are there any downsides to fasting every other day? For example, might go all day without eating impair your ability to think clearly? Surprisingly, as I discuss in my video Is Alternate-Day Intermittent Fasting Safe?, the results appear to be “equivocal.” Some studies show no measurable effects and the ones that do fail to agree on which cognitive domains are affected. Might the cycles of fasting and feasting cause eating disorder–type behaviors, like bingeing? So far, no harmful psychological effects have been found. In fact, there may be some benefit. However, the studies that have put it to the test specifically excluded those with a documented history of eating disorders, for whom the effects may differ. 
     
    What about bone health? No change in bone mineral density was noted after six months of alternate-day fasting despite about 16 pounds of weight loss, which would typically result in a dip in bone mass. However, the researchers did not note any skeletal changes in the control group either, and they lost a similar amount of weight using continuous caloric restriction. They suggested this is because both groups tended to be “more physically active than the average obese American,” getting about 1,000 to 2,000 more steps a day. 
     
    Proponents of intermittent fasting suggest it can better protect lean body mass, but most of the intermittent trials have employed less accurate methods of body composition analysis, whereas the majority of continuous caloric restriction trials used “vastly more accurate techniques.” So, to date, it is not clear if there’s a difference in lean mass preservation. 
     
    Improvements in blood pressure and triglycerides have been noted on intermittent fasting regimens, though this is presumed to be due to the reduction in body fat since the effect appears to be “dependent on the amount of weight lost.” Alternate-day fasting can improve artery function, too, as you can see in the graph below and at 1:55 in my video, though it does depend on what you’re eating on the non-fasting day. For study participants randomized to an alternate-day diet high in saturated fat, their artery function worsened despite a ten-pound weight loss, whereas it improved, as expected, in the lower-fat group. The decline in artery function was presumed to be because of the pro-inflammatory nature of saturated fat. 

    A concern has been raised about the effects of alternate-day fasting on cholesterol. After 24 hours without food, LDL cholesterol may temporarily bump up, but this is presumably because so much fat is being released into the system by the fast. As you can see in the graph below and at 2:33 in my video, an immediate negative effect on carbohydrate tolerance may stem from the same phenomenon—the repeated elevations of free fat floating around in the bloodstream. After a few weeks, though, LDL levels start to drop as the weight comes off. However, results from the largest and longest trial of alternate-day fasting have given me pause. 


    A hundred obese men and women were randomized into one of three groups: alternate-day modified fasting (25 percent of their baseline calories on fasting days and 125 percent calories on eating days), continuous, daily caloric restriction (75 percent of baseline), or a control group instructed to maintain their regular diet. So, for those going into the trial eating 2,000 calories a day, they would continue to eat 2,000 calories a day in the control group. The calorie-restriction group would get 1,500 calories every day, and the intermittent-restriction group would alternate between 500 calories a day and 2,500 calories the next. 
     
    As you can see in the graph below and at 3:32 in my video, with the same overall, average, prescribed calorie cutting in the two weight-loss groups, they both lost about the same amount of weight, but, surprisingly, the cholesterol effects were different. In the continuous calorie-restriction group, the LDL levels dropped as expected compared to the control group as the pounds came off. 

    But, in the alternate-day modified fasting group, they didn’t, as you can see below, and at 3:55 in my video. At the end of the year, the LDL cholesterol in the intermittent fasting group ended up being 10 percent higher than in the constant calorie-restriction group—despite the same loss of body fat. Given that LDL cholesterol is a prime causal risk factor for heart disease, our number one killer—or is even the prime risk factor—this strikes a significant blow against alternate-day fasting. If you want to try it anyway, I would advise you to have your cholesterol monitored to make sure it comes down with your weight. 


    If you’re diabetic, you must talk with your physician about medication adjustment for any changes in diet, including fasting of any duration. Even with proactive medication reduction, advice to immediately break the fast should sugars drop too low, and weekly medical supervision, people with type 2 diabetes who fasted for even just two days a week were twice as likely to suffer from hypoglycemic episodes compared to an unfasted control group. We still don’t know the best way to tweak blood sugar medications to prevent blood sugar from dropping too low on fasting days. 
     
    Even fasting for just one day can significantly slow the clearance of some drugs (like the blood-thinning drug Coumadin) or increase the clearance of others (like caffeine). Fasting for 36 hours can cut your caffeine buzz by 20 percent. So, consultation with your medical professional before fasting is an especially good idea for anyone on any kind of medication. 

    If you missed it, check out Alternate-Day Intermittent Fasting Put to the Test. 
     
    So, with ambiguous cognitive, lean mass, and bone effects, plus these cholesterol findings, I wouldn’t suggest alternate-day fasting for weight loss, but dropping pounds isn’t the only thing this way of eating is purported to do. Check out Does Intermittent Fasting Increase Human Life Expectancy?. 
     
    For other types of intermittent fasting, total fasting, and more on fasting, check out the related videos below. 



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    Michael Greger M.D. FACLM

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  • Flavonoid Benefits from Apple Peels  | NutritionFacts.org

    Flavonoid Benefits from Apple Peels  | NutritionFacts.org

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    Peeled apples are pitted head-to-head against unpeeled apples (and spinach) in a test of artery function. 

    Regularly eating apples may contribute to a lower risk of dying prematurely. “Moderate apple consumption,” meaning one or two apples a week, “was associated with a 20% lower risk of all-cause mortality”—that is, dying from all causes put together—“whereas those who ate an apple a day had a 35% lower risk of all-cause mortality compared with women with low apple consumption.” 
     
    You’ll often hear me talking about a lower or higher risk of mortality, but what does that mean? Isn’t the risk of dying 100 percent for everyone, eventually? As you can see in my graph below and at 0:40 in my video Friday Favorites: For Flavonoid Benefits, Don’t Peel Apples, I present some survival curves to help you visualize these concepts. For example, if you follow thousands of older women over time, nearly half succumb over a period of 15 years, but that half includes those who rarely, if ever, ate apples—less than 20 apples a year. Instead, those averaging more like half a small apple a day lived longer; over the same time period, closer to 40 percent or so of them died. And, those who ate one small apple or about a quarter of a large apple a day survived even longer. 

    Why is that the case? It seems to be less the apple of one’s eye than the apple of one’s arteries. Even a fraction of an apple a day is associated with 24 percent lower odds of having severe major artery calcifications, a marker of vascular disease. You may think that’s an obvious benefit since apples are fruits and fruits are healthy, but the effect was not found for pears, oranges, or bananas. 
     
    Both of these studies were done on women, but a similar effect (with apples and onions) was found for men. We think it’s because of the flavonoids, naturally occurring phytonutrients concentrated in apples. As you can see below and at 2:02 in my video, they’re thought to improve artery function and lower blood pressure, leading to improvements in blood flow throughout the body and brain, thereby decreasing the risk of heart disease and strokes. You don’t know, though, until you put it to the test.


    When I first saw a paper on testing flavonoid-rich apples, I assumed they had selectively bred or genetically engineered a special apple. But, no. The high-flavonoid apple was just an apple with its peel, compared to the low-flavonoid apple, which was the exact same apple with its peel removed. After eating the apples, flavonoid levels in the bloodstream shot up over the next three hours in the unpeeled apple group, compared to the peeled group, as you can see below, and at 2:36 in my video. This coincided with significantly improved artery function in the unpeeled apple group compared to the peeled one. The researchers concluded that “the lower risk of CVD [cardiovascular disease] with higher apple consumption is most likely due to the high concentration of flavonoids in the skin which improve endothelial [arterial] function”—though, it could be anything in the peel. All we know is that apple peels are particularly good for us, improving artery function and lowering blood pressure. 
    Even compared to spinach? As you can see in the graph below and at 3:14 in my video, if you give someone about three-quarters of a cup of cooked spinach, their blood pressure drops within two to three hours. If you instead eat an apple with some extra peel thrown in, you get a similar effect. The researchers concluded that apples and spinach almost immediately improve artery function and lower blood pressure. 
    What’s nice about these results is that we’re talking about whole foods, not some supplement or extract. So, easily, “this could be translated into a natural and low-cost method of reducing the cardiovascular risk profile of the general population.” 

    For more about apples, see the topic page and check out the related videos below. 

    What about dried apples? See Dried Apples vs. Cholesterol. What about apple cider vinegar? Check out Flashback Friday: Does Apple Cider Vinegar Help with Weight Loss?. And what about apples going head-to-head with açai berries? See The Antioxidant Effects of Açai vs. Apples.

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    Michael Greger M.D. FACLM

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