Doctor's Note

For some context, please check out my associated blog post: Avoid Carnitine and Lethicin Supplements

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  • Michael Greger M.D.

    Those familiar with the science will not be surprised by the findings of the two new Harvard studies. Remember the NIH-AARP study I profiled in Meat & Mortality? Half a million people studied—the largest forward-looking study on diet and health in history—and they found the exact the same thing. If the science is so strong why isn’t it reflected in our dietary guidelines? See Dietary Guidelines: Science vs. Corporate Interests. Nor should it surprise that nuts are so healthy. See Halving Heart Attack Risk and Is Peanut Butter Good for You? And speaking of nuts, have you seen the tag cloud? I have videos on more than a thousand nutrition subjects.

    For my thoughts on the American Meat Institute’s reaction to the study, see my Care2 post here.

    • Lucy

      “Those familiar with science”? I’m sorry, but this study is as far from actual science as one can get.

      • Toxins

        I see your a paleolithic advocate. The half science and faulty, misconstrued evidence your group purports is simply NOT science. Dr. Greger covers the paleo diet here on his free e book

        Im sure that if you see more videos on the website, you will come to find that a plant based diet can reverse heart disease, diabetes, autoimmune disease. A high meat diet cannot do these things.

      • Tan Truong

        How about a deeper look:

      • Richard

        You make a provocative comment but include no facts to support it…I have read your blog and they are full of the BS that you claim when studies are contrary to you making money…

  • CapeBreton

    Interesting study. Nuts did stand out once again as offering much benefit despite the high fat content (or perhaps because of the types of fats?). But I was surprised to see that poultry fared much better than legumes as alternatives to red meat. If as Harvard’s Willet says it is the “whole package” that comes with the protein, surely legumes have much better packaging than does factory farmed chicken and turkey? Your comments on that would be appreciated.

    • Toxins
      • Slam

        Then, contaminants should be blamed, first.

    • Archaedus

      I try to raise awareness on the hazards of eat animal-based products. Just last week I put together the following write-up on eating chicken. You may find it informational. Feel free to copy it and share it with friends and family :).

      Many people consider chicken as a health food: you know, ‘gotta get your lean protein.’ Considering that slaughterhouses are killing more birds in one day (25-30 million) then they did in an entire year during the 1930’s, everyone has been dupped. Here are two links comparing 100g of skinless, roasted (I gave the poultry industry the benefit of the doubt) chicken and 100g of red meat hamburger.

      ‘Lean’ protein is nothing more than a gimmic.

      It doesn’t stop at the macronutrients, not by a long shot. Aside from getting fed their own fecies and rendered animal, chickens now grow over twice as fast thanks to genetics and growth stimulants (3lbs bird in six weeks compared to four months). So fast in fact that these animals can not handle the weight of their own internal organs and are rendered breathless after a few steps. So fast that large slaughterhouses must despose of an average of 500 lbs worth of dead chickens due to what is called “flip over” disease- the chickens die from a heart attack as early as one month old. Chickens life expectancy is around 10 years.

      Beside the numerous amount of documentation on cockroach, fly and maggot infestation found in these plants, contamination is also a problem in the poultry industry. According to a USDA micobiologist, there are as many as 50 different opportunities for cross-contamination to occur. The largest offending point of cross-contamination is the chilling pool. Dubbed as ‘fecal soup,’ this large vat is where the recently “cleaned” birds are left to soak in a pool of chilled water that is brimming with all sorts of excrements. An interesting side note is that these corpses absorb an average of 8% of their weight of this filth. Thats right, poultry eaters around America spend more than $1 billion dollars on this bacteria soup that is sold as poultry weight every year.

      What about inspection? The larger slaughterhouses can see as many as 500,000 corpses leave every day. Each inspector has roughly two seconds to inspect each body for over 12 different diseases as well as other abnormalities (by the way, as a result of popular demand in the poultry industry, feces, sores, scabs lesions and broken bones are considered “trimmable conditions” and are no longer condemnable). Federal regulations allow for the sampling of 10 corpses out of ever 15,000. That is less than .1%.

      So what sort of contamination are we talking about? For starters, a reporter who interviewed 84 USDA inspectors wrote that “millions of chickens leaking yellow pus, stained by green feces, contaminated by harmful bacteria, or marred by lung and heart infections, cancerous tumors, or skin conditions are shipped for sale to consumers.” As for bacteria, an Agricultural Department study showed that over 99% of broiler chickens have tracable amounts of E. Coli bacteria, 30% of chicken consumed is infested with salmonella and 70-90% are contaminated with a pathogen called campylobacter. Look it up, campylobacter is no joke. Contaminated chicken kills as little as 1,000 and sickens as many as an estimated 80 million Americans each year.

      This does not include the horrific living conditions, killing practices and environmental
      damage that is a result of eating chicken.

      “Food Inc.”
      “Slaughterhouse” by Gale Einsnitz
      “Mad Cowboy” by Howard F. Lyman

      • Thea

        Archaedus: thanks for the above links.

        For anyone who clicks on the links, you may find yourself confused. The problem is that the two links (at least when I clicked them) defaulted to different units for the chicken vs the beef. Once you have the two go to the same unit, you will see what Archaedus is talking about.

      • Tan Truong

         Thanks Archaedus!

  • Toxins

    The authors of the study on NPR said people can eat red meat 3 times a week, but only a few ounces, the size of a deck of cards. I don’t think anybody is going to follow that advice. They emphasized “moderation”, I hate that word. Moderation kills!

  • Thea

    So timely and so well explained. I wish we could get these videos into our schools.

  • gnewtong

    Did they quantify the increase in mortality? Sure it’s more healthy to eat less red meat, but by how much?

  • MacSmiley

    Just when I think I’ve got all the facts down straight, I read something surprising like this:

    Red Meat Halves Risk of Depression
    [in Australia]

    Evidently there’s a bell curve involved, and the livestock in Australia is mainly grass-fed.

    Is it possible that we vegans and vegetarians could be missing some unknown nutrients found only in meat, especially us long-time plant only eaters?

    • Toxins

      This information is interesting indeed, but it doesn’t tell us too much. We have an abundance of data showing how red meat is causative with chronic illnesses. There is no nutrient in beef we are missing in plants (except b12) and meat in this case is the one missing nutrients! Check out this video about mood and diet.

      • Slam

        PROCESSED red meat is linked to disease.

  • MacSmiley

    We already know about B12, which is why I said I wonder about UNKNOWN nutrients.

    • Toxins

      I was simply pointing out that plants have all that meat has except b12. I directed you to a link showing how mood was related to diet. If one is eating a high meat, low carb diet, they may experience “brain fog” which can give coincidentally give some people the appearance of having a happier mood.

  • MacSmiley

    Just found this today:

    Five Questions: Walter Willett on red meat,0,4545134.story

    I like Dr. Willett’s honesty when answering the question about grass-fed meat: “We don’t know for sure.”

    Previous studies mentioned about mood improvement or “brain fog” are based on the intake of industrial factory-farmed meat, which most of us will agree is a killer, one way or another, especially when consumed in typical American and Atkins portions.

    I wonder if Dr. Willett has seen the Australian study.

    I’d be really interested in any comments Dr. Greger can give on that study. Any flaws in design? Methodology issues? Conflicts of interest in funding?

    Then again, perhaps the secret is a combination of grass-fed beef and Vegemite? ;-)

  • natian

    I cannot find the actualy study, it may not be published yet. I know the study was of 1000 women in the gelong region. that is an small study in one region only. The interesting thing is that the author says that they found that if you eat more than the recommended amount you will also be more likely to suffer depression. So there is a magical number of grams per week/day that reduce the risk. Sounds very inconclusive and I don’t think we need concider it in the light of the large body of data liking ill effects to meat.

  • natian

    Yes I’m all for the plant based diet. I have been total vegetarian, (vegan, but I wear leather shoes and woollen jumpers) for about 30 yrs.

  • Michael Greger M.D.

    For some context, please check out my associated blog post Harvard’s Meat and Mortality Studies!

  • Benoît Boucher

    I’m a vegan myself but I was recently presented this website:
    In this site the author contradicts everything I learned from Dr. Greger and he sites all of his sources. How can I argue against it?

    • guest

      FLAGGED! This is an anti-vegan SPAM post. DELETE.

      • Benoît Boucher

        Please don’t delete it. I would really love to know what is wrong with the studies cited on that website.
        The website LOOKS very credible, even though I’m sure it’s wrong. I’m truly at a loss for arguments against my meat-eating friends and I feel like an expert in nutrition could help.

      • Thea

        guest: There is nothing wrong with Benoit Boucher’s post for this site. We welcome honest questions and disagreements. I hope someone finds the time to give Benoit a good answer. (There is one. I just personally don’t have the 30 second sound bite off the top of my head…)

    • jason

      I’ll respond to some of the points made here.

      1. Vegan Says: “Red Meat Gives You Heart Disease and Type 2 Diabetes”

      Claim: “Two massive studies have looked into this recently, one from Harvard with 1,218,380 individuals, and another European study with 448,568 individuals.They found no link between unprocessed red meat and heart disease, diabetes or the risk of death. The effect was only seen for processed meat.”

      Rebuttal: It is not accurate to say the Harvard study (actually a meta-analsis if studies) found “no link” between red meat and diabetes and stroke. The AVERAGE relative risks (RR) for unprocessed red meat in these studies were:

      CHD (coronary heart disease): 1.0 (same as not eating meat)

      Diabetes: 1.16 (16% higher risk per serving per day. One serving = 100 grams)

      Stroke 1.17 (17% higher risk)

      True, the latter two were not statistically “significant”, but still…

      For processed meat, there is no question of harm. Here are the RR’s from the Harvard meta-analysis:

      CHD: 1.42 (42% higher risk)

      Diabetes: 1.19 (the US study found a RR of 1.53)

      Stroke: 1.14

      Eating some processed meats, like bacon had double the diabetes risk over abstainers. Yet many Paleo and Atkins folks try to make bacon into some virtuous food of the Gods…That’s seriously misguided, given these stats.

      How about the Harvard Meat & Mortality Study Dr. Greger referred to above? I recall it found that eating one serving of meat per day increased one’s risk of ALL CAUSE mortality by 13%, and for processed meat, this was 20%. I recall it DID find that CHD was significantly elevated in unprocessed meat eaters–which should not be surprising, given the saturated fat load, carnitine, and other bad things in meat. The relationship was more or less linear, and people chowing down on 11 oz. of meat a day–which was the high end of the scale–had a RR of all cause mortality of about 1.8, which is close to that of those who smoke a pack a day of cigarettes.

      2. Claim: High-protein diets (high in meat) have actually been shown to help you lose weight, not gain it. They make you feel so full that you eat fewer calories, while boosting your metabolism.”

      Rebuttal: This is simplistic reasoning. One may lose more weight in the short term on a high protein/low carb diet because the food is so boring, or one is expelling more water, but what about the long term consequences? Looking at epidemiological studies, those who eat more plant-based foods generally are thinner. Of course there may be other reasons for that (poverty, disease), but just looking at rich developed nations, the Japanese are thinner than Americans and also eat much less meat–though they do eat more fish. Italians and those on Mediterranean diets also are thinner and eat less meat than Americans…or Germans, and the Italians and Japanese also live the longest among the major nations. The French are actually the least obese in Europe, and do eat more meat than Italians (though still less than Americans), but they don’t live as long as Italians, Spaniards, or even the British.

      3. Claim: Studies show that dietary cholesterol has no effect on blood cholesterol in the majority of people. It may cause a minor increase in some individuals, but a lot of that is coming from HDL and large LDL lipoproteins, which are good things.

      Rebuttal: Again, it is simplistic to say that large LDL is a “good thing”, when it still raises the risk of CHD–just not as much as small LDL particles. HDL is generally a good thing, but may not be needed if total cholesterol is sufficiently low. And who wants to risk that he or she is one of the “some individuals” for whom dietary cholesterol DOES raise blood serum cholesterol? Why take the chance?

      4. Vegan Says: “Saturated Fat Raises Cholesterol and Causes Heart Disease”. Claim: “Saturated fat actually raises HDL (the “good”) cholesterol and changes the LDL cholesterol from small to large, which is considered beneficial.”

      Rebuttal: Notice the sleight of hand here: instead of addressing the issue of raised total and LDL cholesterol , the discussion moves to HDL and the TYPE of LDL (large particle). Plant Positive has many videos in which he debunks the cholesterol ‘confusionists’ who engage in this type of misdirection. Most risk assessments are still done using Total Cholesterol, LDL Cholesterol, and HDL Cholesterol. Probably the best single measure is the TC/HDL ratio (smaller is better), but again, HDL is less important when TC drops below a certain point–probably around 150. The Framingham Risk Score deducts three points when TC is < 160. It's still the best known and most widely used measure of CHD risk.

      Among the studies cited here, I'm familiar with the Chowdhury led one–again, a meta-analysis, which looked at the relation between type of fat consumed and CHD (saturated fat had a RR of 1.03). Plant Positive has a good take-down of this and another similar study:

      Walter Willett, the PI for the Harvard Meat & Mortality Study referenced above, called the Chowdhury study "seriously misleading" and said it should not have been published. But I did find interesting that the study found that Omega-3 fats conferred the lowest relative risk (0.87), and that risk ascended with Omega-6 (0.98), Mono-unsaturated fats (1.0), Saturated fats (1.03), and Trans-fats (1.16). This accords with what many of us felt about the usefulness and harm of these various fats; only the lack of significant risk for saturated fat is really in dispute. Might it depend on the TYPE of saturated fat?

      These RR's pertain to the risk of the top third relative to the bottom third of dietary fat consumption.

      Might risk be much more elevated when saturated fat consumption is higher than merely the top tertile? How about the top quintile or decile? That could be dangerous. Plant Positive discusses some of the weaknesses of the Chowdhury meta-analysis.

      Again, as with the Harvard meta-analysis above, saturated fat did worse than all fats besides trans fats–just as unprocessed meat consumption was associated with higher risk for Diabetes and Stroke (and processed meats with CHD as well as Diabetes and Stroke). Since meat contains a lot of saturated fat, we are generally talking about the same food, and it didn't do well in the very studies cited here to show why there is nothing wrong with eating meat. Well, apparently there is…

      5. Vegan Says: “It is Possible to Get All Necessary Nutrients From Plants”. Claim: There are many nutrients that can not be gotten from commonly consumed plants. This includes vitamin B12, Omega-3s like DHA, as well as vitamin D3.

      Rebuttal: As Dr. Greger pointed out in one of his videos, omnivores suffer from deficiencies in more nutrients than do vegans–at least twice as many. True, one could get adequate folate, Vit. C, E, and potassium on a Paleo type diet which included lots of produce. But it is also possible to get adequate DHA and Vit. D from eating enough ALA and getting enough sunlight, if one lives in the tropics or sub-tropics (below 30 degrees N or above 30 S), or just supplement Vit. D during those months the sun doesn't rise to at least 50 degrees above the horizon. So only Vit. B12 is an issue, and we are talking a few micrograms…

      • Thea

        jason: Wow. This is a really great and thoughtful post. Thanks for taking the time to do this.

        • jason

          I only wish I had enough knowledge to fully comprehend Plant Positive’s critique of the Chowdhury meta-analysis…how it adjusted for cholesterol, for example. I don’t think you’d want to statistically adjust for cholesterol if you were analyzing the effects of saturated fat on health. I was surprised that Chowdhury only found a RR of 1.03 for saturated fat comparing the high tertile with the low–I would have thought it’d be higher.

          Bottom line is that even the studies cited by the low-carbers often fail to support their arguments for the healthfulness of meat, and of course there are many other convincing arguments against meat: aesthetic, economic, environmental…Meat deservedly has a bad rap and more people are realizing this…that the safest level of meat consumption may be zero. For fish, I’m still not sure.

  • Sowmya
  • John

    Last week I read an artice by Dr. Aaron Carroll in the New York Times that “Red Meat is Not the Enemy.” Citing several studies, Dr. Carroll argues that red meat consumption may not be so bad after all, as long as it is done in moderation. Also noted along the way is that strong warnings against cholesterol and salt are overblown. Can you comment on the article and the arguments therein? Thanks.

    • Joseph Gonzales R.D.

      Hi John,

      Thanks for reposting this. I don’t have much to add, but I am hoping others will give their take, as well. I have read it and I think the author makes interesting points, however, one small write-up in the times cannot overlook the massive research on red meat and disease. There is still convincing evidence red meat and processed meats are linked to colorectal cancer and heart disease and diabetes risk. The American Institute for Cancer Research has info on red and processed meat, which may be useful.

      • Slam

        Processed, yes. Unprocessed, grass-fed beef without additives/vaccines/antibiotics, no.