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Carnitine, Choline, Cancer and Cholesterol: The TMAO Connection

Expanding on the subject of my upcoming appearance on The Dr. Oz Show, a landmark new article in the New England Journal of Medicine shows that choline in eggs, poultry, dairy and fish produces the same toxic TMAO as carnitine in red meat, which may help explain plant-based protection from heart disease and prostate cancer.

April 26, 2013 |
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Supplementary Info

Sources Cited

N. D. Ferrari III, L. S. Nield. Smelling like dead fish: A case of trimethylaminuria in an adolescent. Clin Pediatr (Phila) 2006 45(9):864 - 866

H U Rehman. Fish odour syndrome. Postgrad Med J 1999;75:451­452 1999 75(NA):451­ - 452

Z. Wang, E. Klipfell, B. J. Bennett, R. Koeth, B. S. Levison, B. Dugar, A. E. Feldstein, E. B. Britt, X. Fu, Y.-M. Chung, Y. Wu, P. Schauer, J. D. Smith, H. Allayee, W. H. W. Tang, J. A. DiDonato, A. J. Lusis, S. L. Hazen. Gut flora metabolism of phosphatidylcholine promotes cardiovascular disease. Nature 2011 472(7341):57 - 63

K. Rak, D. J. Rader. Cardiovascular disease: The diet-microbe morbid union. Nature 2011 472(7341):40 - 41

M. G. Busby, L. Fischer, K.A. da Costa, D. Thompson, M.H. Mar, S. H. Zeisel. Choline- and betaine-defined diets for use in clinical research and for the management of trimethylaminuria. J Am Diet Assoc 2004 104(12):1836 - 1845

J. E. Lee, E. Giovannucci, C. S. Fuchs, W. C. Willett, S. H. Zeisel, E. Cho. Choline and betaine intake and the risk of colorectal cancer in men. Cancer Epidemiol. Biomarkers Prev. 2010 19(3):884 - 887

NA. Choline: There's something fishy about this vitamin. Harv Health Lett 2004 30(1):3

E. Ackerstaff, B. R. Pflug, J. B. Nelson, Z. M. Bhujwalla. Detection of increased choline compounds with proton nuclear magnetic resonance spectroscopy subsequent to malignant transformation of human prostatic epithelial cells. Cancer Res. 2001 61(9):3599 - 3603

Subcommittee on the Tenth Edition of the Recommended Dietary Allowances, Food and Nutrition Board, Commission on Life Sciences, National Research Council. 1989. Tenth Edition of the Recommended Dietary Allowances.

Koeth RA, Wang Z, Levison BS, Buffa JA, Org E, Sheehy BT, Britt EB, Fu X, Wu Y, Li L, Smith JD, Didonato JA, Chen J, Li H, Wu GD, Lewis JD, Warrier M, Brown JM, Krauss RM, Tang WH, Bushman FD, Lusis AJ, Hazen SL. Intestinal microbiota metabolism of l-carnitine, a nutrient in red meat, promotes atherosclerosis. Nat Med. 2013 Apr 7.

Zeisel SH, Mar MH, Howe JC, Holden JM. Concentrations of choline-containing compounds and betaine in common foods. J Nutr. 2003 May;133(5):1302-7.

J. Demarquoy, B, Georges, C. Rigault, M.C. Royer, A. Clairet, M. Soty, S. Lekounoungou, F.L. Borgne. Radioisotopic determination of l-carnitine content in foods commonly eaten in Western countries. Food Chemistry, Volume 86, Issue 1, June 2004, Pages 137–142

W.H. Wilson Tang, M.D., Zeneng Wang, Ph.D., Bruce S. Levison, Ph.D., Robert A. Koeth, B.S., Earl B. Britt, M.D., Xiaoming Fu, M.S., Yuping Wu, Ph.D., and Stanley L. Hazen, M.D., Ph.D. Intestinal Microbial Metabolism of Phosphatidylcholine and Cardiovascular Risk. New England Journal of Medicine 368:1575-1584.

E. L. Richman, S. A. Kenfield, M. J. Stampfer, E. L. Giovannucci, J. M. Chan. Egg, red meat, and poultry intake and risk of lethal prostate cancer in the prostate-specific antigen-era: Incidence and survival. Cancer Prev Res (Phila) 2011 4(12):2110 - 2121

E. L. Richman, M. J. Stampfer, A. Paciorek, J. M. Broering, P. R. Carroll, J. M. Chan. Intakes of meat, fish, poultry, and eggs and risk of prostate cancer progression. Am. J. Clin. Nutr. 2010 91(3):712 - 721

M. Johansson, B. Van Guelpen, S. E. Vollset, J. Hultdin, A. Bergh, T. Key, O. Midttun, G. Hallmans, P. M. Ueland, P. Stattin. One-carbon metabolism and prostate cancer risk: Prospective investigation of seven circulating B vitamins and metabolites. Cancer Epidemiol. Biomarkers Prev. 2009 18(5):1538 - 1543

C. Nanni, E. Zamagni, M. Cavo, D. Rubello, P. Tacchetti, C. Pettinato, M. Farsad, P. Castellucci, V. Ambrosini, G. C. Montini, A. Al-Nahhas, R. Franchi, S. Fanti. 11C-choline vs. 18F-FDG PET/CT in assessing bone involvement in patients with multiple myeloma. World J Surg Oncol 2007 5(NA):68

E. L. Richman, S. A. Kenfield, M. J. Stampfer, E. L. Giovannucci, S. H. Zeisel, W. C. Willett, J. M. Chan. Choline intake and risk of lethal prostate cancer: Incidence and survival. Am. J. Clin. Nutr. 2012 96(4):855 - 863

E. Ackerstaff, B. R. Pflug, J. B. Nelson, Z. M. Bhujwalla. Detection of increased choline compounds with proton nuclear magnetic resonance spectroscopy subsequent to malignant transformation of human prostatic epithelial cells. Cancer Res. 2001 61(9):3599 - 3603



Earlier this month, a research team at the Cleveland Clinic offered another explanation as to why meat intake may be related to mortality. "Numerous studies have suggested a decrease in atherosclerotic disease risk—our #1 killer—in vegan and vegetarian individuals compared to omnivores, [but we've just assumed this was due to reduced intake] of dietary cholesterol and saturated fat…" But what they found was that within 24 hours of carnitine consumption—eating a sirloin steak, taking a carnitine supplement--certain gut bacteria metabolize the carnitine to a toxic substance called trimethylamine, which then gets oxidized in our liver to TMAO, trimethylamine-n-oxide, which then circulates throughout our bloodstream.

The way we know it's the gut bacteria that's doing it, is that if you give people antibiotics to wipe out gut bacteria, you can apparently eat all the steak you want without making any TMAO, but then if you wait a couple weeks until your gut bacteria grows back, you're back to the same problem. 

What's so bad about this TMAO stuff? Well it may increase the buildup of cholesterol in the inflammatory cells in the atherosclerotic plaques in our arteries, increasing our risk of heart attack, stroke, death, and if that isn't enough, cardiac surgery as well.

So how do you stay away from carnitine? Well there's zero dietary requirement; our body normally makes all that we need. The problem is that the bodies of other animals also makes all that they need so when we eat them, their carnitine can end up in our gut for those bacteria to feast upon, resulting in TMAO. Some animals make more than others; carnitine is concentrated in red meat, so then why's there also clipart of white meat, dairy, and eggs?

That's what most media reports missed—even though it's the very first sentence of the paper. How do you think the researchers even thought to look into carnitine? Because gut bacteria can turn choline into TMAO too! Given the similarity in structure between carnitine and choline, they figured they’d find that same transformation into TMAO, and that's exactly what they found.

Eggs, milk, liver, red meat, poultry, shell fish and fish are all believed to be major dietary sources of choline, and hence TMAO production. So it's not just red meat. The good news is that this may mean a new approach to prevent or treat heart disease, the most obvious of which would be to limit dietary choline intake. But if that means decreasing egg, meat and dairy consumption, the new approach sounds an awful lot like the old approach.

Unlike carnitine, we do need to take in some choline, so should vegans be worried about the modest amounts of choline they're getting from beans, veggies, grains, and fruit? And same question with carnitine. There's a small amount of carnitine found in fruits, veggies, and grains as well. Of course it's not the carnitine itself we're worried about, but the toxic TMAO, and you can feed a vegan a steak—literally, an 8-ounce sirloin (anything in the name of science). Same whopping carnitine load, but basically no TMAO was produced. Apparently, the vegans don't develop those TMAO-producing bacteria in their gut, and why should they?It's like the whole prebiotic story. You eat a lot of fiber, and you select for fiber-consuming bacteria, and some of the compounds they make with fiber are beneficial, like the propionate I've talked about, that appears to have an anti-obesity effect. Well, if we eat a lot of animal products we may instead be selecting for animal-product digesting bacteria, and it appears some of those waste products, like the trimethylamine may be harmful.

Even if you eat vegan, though, you're not necessarily out of the woods. If you regularly drink carnitine-containing energy drinks, or take carnitine supplements—or lecithin supplements, which contain choline, presumably you'd foster and maintain those same kinds of TMAO-producing bacteria in your gut and increase your risk of heart disease and, perhaps, cancer.

About two million men in the U.S. are living with prostate cancer, but that's better than dying from prostate cancer. Catch it when it's localized and your 5-year survival is practically guaranteed, but once it really starts spreading your chances drop to 1 in 3. "Thus, identification of modifiable factors that affect the progression of prostate cancer is something that deserves study. So Harvard researchers took more than a thousand men with early stage prostate cancer and followed them for a couple years to see if there was anything in their diet associated with a resurgence of the cancer, such as spread to the bone.

Compared to men who hardly ate any eggs, men who ate even less than a single egg a day had a significant 2-fold increased risk of prostate cancer progression. And maybe it's the choline.

A plausible mechanism that may explain the association between eggs and prostate cancer progression is high dietary choline. Egg consumption is a determinant of how much choline you have in your blood, and higher blood choline has been associated with a greater risk of getting prostate cancer in the first place. So the choline in eggs may both increase one's risk of getting it and then having it spread, and also having it kill you.

Choline intake and the risk of lethal prostate cancer. Choline consumption is associated not just with getting cancer and spreading cancer but also with a significantly increased risk of dying from it. Those who ate the most had a 70% increased risk of lethal prostate cancer. Another recent study found that men who consumed 2 and a half or more eggs per week—that's just like one egg every three days--had an 81% increased risk of lethal prostate cancer. Now it could just be the cholesterol in eggs that's increasing fatal cancer risk, but it could also be the choline.

Maybe that's why meat, milk, and eggs have all been associated with advanced prostate cancer, because of the choline. In fact, choline is so concentrated in cancer cells, if you follow choline uptake you can track the spread of cancer through the body. But why may dietary choline increase the risk of lethal prostate cancer? It may be the trimethylamine oxide. The Harvard researchers speculated that the TMAO from the high dietary choline intake may increase inflammation and this may promote progression of prostate cancer to lethal disease.

In fact, just yesterday in the New England Journal of Medicine that same Cleveland Clinic research team that did the carnitine study repeated the study, but this time instead of feeding people a steak, they fed people some hard-boiled eggs. Just as they suspected, a similar spike in that toxic TMAO, so it's not just red meat. And the link between TMAO levels in the blood and strokes, heart attack, and death was seen even in low-risk groups like those with low-risk cholesterol levels. So eating eggs may increase our risk regardless what our cholesterol is, because of the choline. 

It's ironic that the choline content of eggs is something the egg industry actually boasts about. And the industry is aware of the cancer data. Through the Freedom of Information Act I was able to get my hands on an email from the executive director of the industry's Egg Nutrition Center to an American Egg Board executive talking about how choline may be a culprit in promoting cancer progression, "Certainly worth keeping in mind as we continue to promote choline as another good reason to consume eggs."

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by Jonathan Hodgson.

To help out on the site please email


Dr. Michael Greger

Doctor's Note

It was such an honor to be on The Dr. Oz Show last week. It's expected to air during sweeps week next month. I'll announce the date on the Facebook page. 

The TMAO story is such a fascinating twist. It helps explain, for example, Harvard’s Meat and Mortality Studies. The role of the inflammatory "foam" cells (so-called because they're so packed with cholesterol they look foamy under a microscope) affected by TMAO is explained in my video series that starts with Arterial Acne and Blocking the First Step of Heart Disease.

When I say we normally make all the carnitine we need, there's a rare genetic inborn error of metabolism that affects as many as 1 in 40,000 births, which can result in a need for dietary carnitine. Learn more in my video When Meat Can Be a Lifesaver.

What does carnitine do? It's involved in energy production in the mitochondria ("power plants") in our cells. The enzyme that uses carnitine to help us burn fat, carnitine palmitoyl transferase, is actually upregulated by about 60% in those eating meat-free diets, which may help explain why those eating plant-based diets tend to be slimmer. More details in my video How to Upregulate Metabolism.

The prebiotic videos I feature are Fawning Over Flora and Boosting Good Bacteria in the Colon Without Probiotics, though other videos describing the beneficial products our friendly flora make from the plants we eat include:

And for another behind-the-curtain peek at the egg industry, see Eggs vs. Cigarettes in Atherosclerosis and Egg Industry Blind Spot.

For some context, please check out my associated blog posts: Avoid Carnitine and Lethicin SupplementsWhy Are Eggs Linked to Cancer Progression?, and Top 10 Most Popular Videos from 2013

If you haven't yet, you can subscribe to my videos for free by clicking here.

  • Plantstrongdoc

    And the answer is NOT to pollute the meat further with antibiotics in the hope of wiping the bad-meat-eating-bacteria out. Probably the next suggestion from the meat industriy…

    • Dan Lundeen

      Don’t give them any ideas! But it does make you wonder if, in a lot of these studies, they will need to start enterotyping the test subjects and the food contaminants to make sense of the data.

  • Brian Humphrey

    WOW!! I was all set to buy L-Carnitine supplements online! Thanks Dr.Greger!! What about about carnosine? I know it has documented affects againts AGE’s.

  • Brian Humphrey

    WOW!! I was all set to buy L-Carnitine supplements online! Thanks Dr.Greger!! What about about carnosine? I know it has documented affects againts AGE’s.

    • Ralph

      I’ve been taking carnitine and lecithin for several years- but today is the day I stop! I wonder how many of the 35 or so other supplements I take are harmful. From previous videos here, vitamins B-12 and D are okay, but I think I may not renew my subscription to Life Extension. By the way, instead of taking carnosine, you can take beta alanine which is much less expensive and produces carnosine in your body. Carnosine is broken down to beta alanine by your digestion anyway.

      • Don Forrester MD

        The only supplement I routinely recommend for patients is Vitamin B12. In my experience Life Extension can be a great way to get laboratory testing done. We used their services in the last Meals for Health program in the Berkeley/Oakland area. I avoid any other supplements unless a deficiency is documented. Unfortunately given the distribution of normal laboratory values in the normal population it is easy for medicine to change recommendations and to start recommending supplements or medications for people who are normal. If your Vitamin D level is low the best Rx is sunlight. Taking vitamin D supplement doesn’t improve the arterial system by the liberation of Nitrous Oxide from subcutaneous stores. Dr. Greger has yet to run a video on this subject… see the talk: Richard
        Weller: Could the sun be good for your heart? Of course their are times I recommend Vit D but very few.


        • MacSmiley

          There are times I recommend TEDTalks like this one. But lately, they’ve been scraping the bottom of the barrel with Taubes acolytes Attia and Teicholz.

  • rick

    Glad to hear you’re going to be on Dr. Oz. Not only will that help you to get the word and science out, but hopefully help with their fundraising!

    • VegAtHeart

      FYI: Dr. Greger’s appearance on Dr. Oz is available here.

      • Thea

        VegAtHeart: Thanks so much!! I’ve been wanting to see that clip and previous efforts to find it didn’t work. Much appreciated.

        • VegAtHeart

          You’re welcome!

  • Sue Solin

    I saw something about this on CBS news earlier this week. INSTEAD of taking the opportunity to promote a plant-based diet they talked about drug companies hopefully being able to make a new drug to treat TMAO (insert face palm here). When are they going to figure this out. I wish HLN’s evening new show would include Dr. Greger several times a week. A reoccurring nutrition segment on national news would be wonderful and Dr. Greger keeps his information short and concise and throws in a little humor. It would be perfect for the masses!

  • Scott

    I am currently taking the more bio available Acetyl-L Carnitine as a supplement for some of the studies dealing with it’s protective qualities toward hearing loss. Being a 25 year low fat eating Vegan, can I assume that I am fairly safe from the TMAO production and it’s effects you are referring to?

  • Douglas McKee

    Don’t do this Michael. You are falling into the same trap they have.

    It is not the specific ingredients, either carnitine or lecithin, that is the problem. It is the gut flora that has developed in response to a refined ingredient and high sugar diet.

    Remember the 1875 patients were referred to their heart clinic because they already were really sick. Their gut flora was mainly firmicutes and some tenericutes, species that are not resident in a healthy gut flora.

    Restoring a healthy flora is the key here, not blaming highly processed ingredients that merely feed the bad bacteria. The liposaccharides from healthy flora does not raise TMA.

    Consuming polyphenols in veggies and fruits are the natural way to decrease firmicutes and support bacteroidetes and decrease heart disease. Antibiotics are not.

    • Aurametrix Inc.

      Yes, it’s more about the gut flora than isolated ingredients. Japan has one of the lowest rates of heart disease, South East and South Central Asia have the lowest rates of prostate cancer. They eat fish and eggs. But their gut bacteria is different to begin with. US microbiomes are more focused on degrading amino acids, while, for example, Malawian microbes are focused on digesting starches.

      • johnnywhite

        Very interesting …thanks for this post

    • elsie blanche

      Douglas, are you suggesting that meat consumption is not the culprit here? Thank you for more clarity on your previous comments.

      • MacSmiley

        My thought as well. Japanese eat lots of sugar. Meat, not so much. Sugar is likely an issue here in the US because of the lack of whole plant foods in the diet and the excess calories sugar contributes here. In other words, portion sizes count.

    • MacSmiley

      Dr Greger is in no way advocating the use of antibiotics to treat CVD. Antibiotics merely confirmed the hypothesis that gut bacteria were involved in the conversion of carnitine and lecithin to TMAO. Which bacteria involved has not yet been determined.

      By now, I think it can be safely stated that pretty much anything we put down our gullets affects the ecosystem in our digestive tract.

  • AileenO

    When are you on Dr. oz?

    • Thea

      AileenO: Friendly tip: Dr. Greger has a ‘Doctor’s Note’ under each of the videos. Above, you can see that Dr. Greger gives a link to a Facebook page where he will announce his Dr. Oz showing when he knows it. Hope that helps.

  • Farraday Newsome

    This was an awesome video Dr. Greger. Your research is so up-to-date and wide-reaching. Your presentation is engaging and succinct. Thank-you for this and so many excellent videos.

  • Guest

    I think you should not say compared to omnivores but compared to meat
    eaters or vegetarians. As it gives the false idea that people are
    omnivores when really we are herbivores. So really people are not
    omnivores but herbivores that eat meat. Just like Panda’s are carnivores
    that eat bamboo.

    • Guest2

      The similarity of our body design to that of the great apes make me wonder if we’re not actually frugavores. Apes eat mostly fruit and greens. Some eat grains- raw. Since we produce more amylase that most apes, it seems that we’re adapted to grains too. Chimps seem to be an exception. They also eat an occasional monkey, perhaps as a ritual to show dominance. Herbivores eat mostly grass, I’ve tried it in juice form once or twice (as wheat grass) and I find it to be disgusting. So, I’m afraid I wouldn’t make a good herbivore.

      • Kelly

        Frugivores…LOL! :)

    • Kelly

      Nonsense. Humans are omnivores, sheesh.

  • Stephen Lucker Kelly

    I think you should not say compared to omnivores but compared to meat eaters or vegetarians. As it gives the false idea that people are omnivores when really we are herbivores. So really people are not omnivores but herbivores that eat meat. Just like Panda’s are carnivores that eat bamboo…

  • Stephen Lucker Kelly

    I don’t know if I missed it but I didn’t catch any recommendations about Carnitine or Choline? And how much we need to get of both and or good sources in food? What do you recommend?

    • Toxins

      No need to seek these nutrients. Carnitine is produced by our own body and choline is available in a variety of plant foods in adequate amounts. Choline deficiency is quite rare in healthy populations.

  • Michael Mooney

    There’s a problem with this notion.

    Studies in humans have shown that neither phosphatidylcholine nor choline-rich foods produce detectable increases in trimethylamine.

    • Darryl Roy

      With reference to your second citation, the major weakness I see in the Hazen studies at the heart of this video is that cold water fish can contain significantly greater TMAO than the carnitine content of red meat, yet fish consumption has a far weaker correlation with cardiovascular disease than red meat consumption.

      I suspect that red meat’s combination of numerous inflamatory hazards (carnitine/TMAO, saturated fat, cholesterol, endotoxins, AGEs, Neu5gc, heterocyclic amines, persistant organic pollutants, etc) acting in concert after every meal, and its lack of significant anti-inflammatory components like omega-3 fatty acids, may result in it being a particularly potent cause of cardiovascular disease. More so than any one of its components in isolation.

      Serum TMAO levels in a cohort of Western omnivores are very strongly correlated with cardiovascular risk (, but its also possible that that the TMAO is serving as a biomarker for consumption of a whole range of hazards, rather than a singular risk. At present, there aren’t any studies on other populations (ie. those on traditional Japanese diet) where serum TMAO may arise mostly from non-red meat sources.

      To tease out whether TMAO alone is a dominant cause of atherosclerosis in humans might require an impractical or unethical study like feeding Monster energy drinks (more carnitine than a Porterhouse steak) to vegans for an extended period.

      • Thea

        Darryl: re: “I suspect that red meat’s combination of numerous inflamatory hazards … acting in
        concert after every meal… More so than any
        one of its components in isolation.”

        That makes sense to me and is quite in line with the approach that is presented in the book The China Study. The idea is that we can work on understanding individual mechanisms on how things work, but diseases rarely operate on a single mechanism. It is the whole system that comes together to create effects. At least, that’s my understanding of the point of the book.

        Anyway, I was moved to reply to your statement, because literally hours before seeing this video, I had found what looks like the best recipe in the world for making vegan butter!!:
        BUT it has lecithin.

        I wouldn’t be using the vegan butter (fat/pure oil) all the time anyway. I am trying to go in a generally more healthy direction. But I still want the occasional treat and say butter on pancakes would be a real treat.

        Thus, the vegan butter idea was really exciting. This
        video raised the question in my head about how harmful the lecithin would be in the vegan butter. Which gets to your point: I’m hoping that by itself, as part of vegan butter in a vegan diet, that the lecithin wouldn’t be so bad – at least no more bad than any plant-based fat.

        That’s what I’m going with anyway, because when
        I get all of the ingredients, I’m going to give it a try. Thanks for posting your thoughts. You helped me put things into perspective.

    • James Lightning Wilks

      Mr. Mooney, sorry, could you explain your use of first reference when it states, “A significant fraction of ingested choline is destroyed by enzymes within gut bacteria, forming trimethylamine”

  • dm conner

    and then there’s this:

    May 2011 Lecithin Supplements and Breast Cancer Risk

  • Deb P

    Very interesting. I have two questions.
    First, if vegans, not having the gut flora that produce TMAO, are somewhat protected, would not this same protection apply to eating eggs as well?
    Second, does it make any difference if the eggs come from pastured, naturally fed hens?

    • Plantstrongdoc

      Nope – eggs are eggs. Some come from happy chickens, some from battery chickens and some come from organic chickens (which BTW can be battery chickens), but the composition of the egg is similar. If you are lucky – a little less dioxin….

    • b00mer

      I could be misunderstanding your question, but eating eggs regularly will change your gut flora. You will no longer have the gut flora of a vegan i.e. you would no longer be a “protected” vegan.

  • Guest

    Hi, Dr Greger. Does this means we have to stay away from cauliflower, almond, and peanuts too? Last time I check 100g of cauliflower contains 45.2mg of choline. That’s close to 1/2 of an egg.

    • Devin Wiesner

      My guess is that further studies will be completed on choline and we will have a better picture of it’s effects on intestinal microflora. My experience is that most egg based entrees, use 2 to 4 eggs per serving. So some people are consuming a lot of choline and quite frequently. Compounds in cauliflower (like glucosinolates) have an anti-cancer effect and are cardio-protective. So I’m just avoiding eggs and keeping cruciferous vegetables on my plate and flax seeds in my smoothies…I’m not a huge fan of peanuts, I like the taste..however I think there are options with more nutrients.

  • prez

    Here’s the problem I have. The big issue with eggs seems to that the bacteria in the gut break down the lecithin in eggs and produce TMAO–which causes damage to the artery walls. Just this past week we saw the research promoting fenugreek as an herbal wonder which helps with everything from body building to sexual health. But fenugreek is high in lecithin. Why is the lecithin in fenugreek good for us and the lecithin in eggs a killer?

  • SG

    I assume egg whites are OK?

  • chas j

    I take 650 mg of betaine per meal for protein digestion. Does this pose a risk insofar as choline is converted into betaine? Is is that choline itself to excess is dangerous or is it the betaine as an end product?

  • Steve Henwood

    Der Dr. Gregor,
    Outstanding video! I had totally missed the choline connection!
    It would be interesting to do some self experimentation by altering our diet in various ways for a few months and then testing our blood levels of TMAO, choline, & L carnitine, Do you know anything about the availability of blood tests for TMAO for the everyday person not in a research study? It would be interesting also to find out if supplementation with various kinds of probiotics and fiber might affect the proliferation of L-carnitine and choline metabolizing bacteria in people who do eat specific amounts of meat, and to answer the question of to what degree can competing bacteria reduce the populations of the L-carnitine & choline loving bacteria.
    Lastly, some of the other commenters raised some very good questions. We would love to hear your response to them. So far most of these questions have not been addressed.

    • Darryl Roy

      Urine TMA/TMAO is a not uncommon test for the genetic disorder trimethylaminuria, where the ratio, rather than absolute levels, is important – you may need to confirm reporting if you want to experiment. A list of labs from around the world that will perform this test:

  • Karina

    I am so happy to see this video. I was vegetarian and now I am full vegan, but I kept wondering if I should supplement choline to get the brain boost. Now I know it is not necessary. Will you make a video about taurine in vegans? I saw in another video that taurine helps to protect against AGE’s. Thank you for these videos!

    • Darryl Roy

      I think I wrote that, having just read one of M McCarty’s many non-peer reviewed hypotheses:
      On further study, taurine has cytoprotective and atheroprotective effects, but evidence of inhibition of AGE formation is circumstantial (and weak, compared to some other nutrients).

  • MacSmiley

    Why restrict your Dr Oz airdate announcement to Facebook? Some of us value out privacy too much to entrust it to Zuckerberg and Company. Please widen out your announcements to other communication channels.

    • WholeFoodChomper

      Agreed. I rarely if ever venture into Facebook territory.

    • shaniqua

      Maybe Oprah will give Dr. Greger his own show on her network.

      • MacSmiley

        That might be tempting, though I’m not sure Dr Greger wants the commercial nature of show business to taint his message.

  • Cindy Plachinski

    It boggles my brain cells why anyone would eat meat, drink milk, consume cheese and eggs once scientists are finding these links to diseases that are preventable just by NOT eating this stuff. Is it the same idea as when people smoke? They know it causes disease but keep doing it? I still cannot figure that one out, except for the addictive properties, but are some humans addicted to meat, milk, eggs and cheese or is it just an unfortunate quirk of our current society? Why don’t doctors just tell people to STOP eating stuff that causes disease? Are they afraid of the meat and dairy industry?

    • Plantstrongdoc

      When it comes to diet and disease most docorts are ignorants. I dont think they are afraid, they just dont know the abundance of science that backs up a whole food plant based diet. In the medical community you dont hear much about nutrition. My mother (type 2 diabetic) says that I am the only doctor ever, who has told her that she is to fat. The only one! I have heard about a GP who recommended more read meat to a patient, because she allegedly lacked proteins in the blod (the story made no sense)! I know a person who went to his doctor to get some help to loose weight, because he was just diagnosed with type 2 diabetes, and the doctor replyed “you are not overweight” – despite the obvious fact that the man was at least 20 kg overweight. I was actually searching for something else, but found informations about this topic by chance.

    • barbara parker

      so many rhetorical questions! here is my take as an informed consumer who didn’t know this stuff until seeing ‘Forks Over Knives’ despite ‘paying attention’ to nutrition for many years. ordinary people don’t know this stuff. Dr. Greger’s recent video on the McGovern Report was an eye-opener. doctors don’t know this stuff! there is very little attention paid to nutrition in medical school and the pharmaceutical industry ‘friends’ them after school. lastly, there is inertia, a HUGE factor in why people don’t change.

  • Brandon Becker

    I’m vegan and took a 500 mg carnitine supplement for a few months to see if I felt any different. No difference at all. I did the same with 250 mg choline (and 250 mg inositol in the same pill) and also felt no difference. Seeing as now it may be harmful to use these supplements, I don’t plan on buying them again. What is your suggested intake of choline from food? What about carnitine, which I assume our body makes from eating foods high in lysine and methoinine?

    • Brandon Becker

      Update: Before I saw this video I bought a small bottle of acetyl-l-carnitine to test out. I’ve taken acetyl-l-carnitine at the levels from 250 mg – 750 mg daily for the last 8 days and, unlike l-carnitine which I didn’t feel anything, the acetyl form makes me feel bad. It’s causing heart palpitations and I have no history of any heart problems. I’m stopping this now and dumping the rest of the bottle. I will go the safe (and free!) route of just eating food and having my body produce whatever carnitine is needed on it’s own.

  • WholeFoodChomper

    Is choline present in egg whites, egg yolks, or both? Does eating just the egg whites have the same effect as eating a whole egg (in regards to choline)?

  • dr.jim

    Is that choline in the whites of the eggs also ?

  • Moragh Lippert

    I agree with all this and the wonderful and proven benefits of a plant based diet. However, a friend who follows Weston Price Fndn and Mercola sent me this link. Any comments?

    • b00mer

      Your link doesn’t appear to have worked; you’ve included the link to this video.

      Regarding Weston Price and Mercola, I would find it hard to critique either of them because they just can’t be taken seriously. In the blog world maybe, but in the world of peer-reviewed research, they’re just not considered legitimate sources. The few Mercola articles I’ve read, when I actually checked his sources, stated completely different conclusions than what he was peddling in his article. The Weston Price Foundation is based on the idea that we should ignore all of the clinical, epidemiological, and basic science research that has been done to date, and base our nutrition decisions on what a dentist from the 1920′s thought.

      However, if your friend has peer-reviewed modern research articles that they wish to share (since that is what this site is based on), I’m sure many would be happy to discuss them.

      • Psych MD

        I am posting here only because I searched in vein for a reference and found none. Dr. Greger, what is your opinion of coenzyme Q10 supplementation?

  • Carl Newmeyer
  • Carl Newmeyer
  • Christine T.

    Dr Gregor,
    Not to change the subject, I was wondering if and when you might discuss
    Chromium and linoleic acid. I would be interested in that topic.
    Thank you and I enjoy reading all your presented research online.

  • Wegan

    Does the last chart show eggs or radioactive lecithin?

  • foxfyr

    Please take a look at yet another study (“L-Carnitine in the Secondary Prevention of Cardiovascular Disease: Systematic Review and Meta-analysis”)

    Now, another study delivered by the Scarecrow from the Wizard of Oz delivers a study asserting that Carnitine, a compound found in red meats, appears to be cardioprotective in a systematic review — a finding that comes barely a week after a Nature Medicine study sounded an alarm about the heart risks of carnitine in the form of derivative TMAOs.

    OK….is this a case where the substance (LCar) itself is beneficial, but the by-products are not? Or…
    And if so, how does one balance or even evaluate the balance between the two effects.


    • Michael Greger M.D.

      Thanks for the question foxfyr! The study to which you’re referring can be found here.

      We’ve known for over 20 years ( that large doses of carnitine given intravenously in people within hours of a heart attack may have an antiarrhythmic effect, presumably by facilitating glucose oxidation in the failing heart muscle. Because it’s given directly into the bloodstream, it enters our body the way our own body creates it (bypassing the gut). Only when carnitine enters the gut could that toxic TMAO be made by the gut bacteria. In the context of a heart attack, even carnitine supplements given orally could help the patient live through that critical first post-MI period by lowering risk of ventricular arrythmia even if it might be contributing to further plaque progression elsewhere in the heart. Hopefully we will all never be placed in that situation by preventing the heart attack in the first place by decreasing our intake of carnitine, choline, cholesterol, saturated fat, and trans fats found in animal foods and junk. Check out my video series starting with Arterial Acne.

  • Rob English

    The Linus Pauling group and others are saying that the adequate itake of choline for adults is betwem 425 and 550 mg per day. That’s something like seven cups of flaxseed, peanuts or almonds, or two-plus pounds of coliflower. What does Dr. Greger recommend?



    Serving size:

  • Neal

    I just read in Healthy at 100 by John Robbins that he recommends L-Carnotine for vegans, and I started taking supplements, so I guess I should stop taking it??


    • Michael Greger M.D.

      Yes, you probably should.

  • Dave

    My question Is whether L-Carnitine HCI, 500 mg is safe to to take?

  • abeleehane

    I don’t want to be a pest, but people refer me to Weston Price inst. analysis(Chris Masterjohn) of the studies above. I don;t have the tools or knowledge to refute any of it. I was wondering if there was any data pertaining to this “rebuttal”
    I personally can’t take the Weston Price Institute seriously, but Mr Chris Masterjohn seems to have a following, and giving it a flick and wishing it away doesn’t seem responsible.

    • Thea

      abeleehane: Perhaps this will help you: Plant Positive on You Tube has several videos that competently address several of the problems with Weston Price information. I would guess that there are also other sources of information refuting what Price sells as good science. I just haven’t bothered to look further myself.

      Here’s one link that will get you started:

      Plant Positive posts a series of videos. The above link is just to one of video in the series. If you (or others you want to educate) are interested, I recommend watching as much of the series as you can. Plant Positive addresses all sorts of claims by paleo and other types of diets.

      Good luck!

      • abeleehane

        Thank you very much, the videos seem to be well made and science based.

        • Dan Lundeen

          PlantPositive is an Excellent Resource! FWIW Dr. Greger wrote the book debunking low carber truthiness, titled Carbophobia, and you can get a copy free or at very low cost, check out Don’t expect Dr. G to go over everything again on this message board, and if you watch just a fraction of his 1600+ videos you’ll see he already has.

  • Emily

    Dr. Greger, thank you for this valuable information. It does, however, present a personal problem for me. I had been vegan for a few years but for some reason could not stop eating all day long. I believe this has to do with undiagnosed hypoglycemia. At any rate, I find that the only dish that fills me up and prevents me from grazing and experiencing massive food cravings is stir-fried brown rice, veggies, and eggs in the morning. I eat vegan food for the rest of the day. I have tried protein powders, nuts, tofu, beans, etc. and none of the vegan sources of protein have the blood-sugar leveling effect of the eggs and rice. Do you have any suggestions? Is there some magical combination of vegan foods I could eat in the morning that would help keep my blood sugar level throughout the day?

  • Aussie86

    Is a guy named Tim, might know him from his youtube channel Running Raw. Raw vegan and marathon runner. Great explanation about TMAO.

  • Food for Living

    Interesting! Just curious – if, when vegans eat a steak it doesn’t increase their TMAO levels, because they lack the gut bacteria to metabolized carnitine or choline into TMAO – then why would vegans, who eat foods or take supplements containing choline, be at increased risk for heart disease and cancer due to TMAO’s?


    The Cleveland Clinic study that got this rolling was bogus,
    judging by a detailed, persuasive analysis from UCONN nutrition PhD candidate Chris Masterjohn:

  • Mark L.

    This study you cite has a number of serious flaws, and the connection between carnitine and heart disease is weak at best:

    Sometimes it’s best to examine the methodology of the research a bit closer as well as the results to see if all extraneous variables are accounted for. Instead, it appears you are agreeing with it’s conclusions prematurely as a result of your own particular bias on nutrition. Not that I don’t agree with the majority of your input, but in this particular case it is flawed.

  • Lissen Up

    These data raise good questions. More data need to address additional factors possibly associated with TMAO increases and then begin to narrow the correlates down to plausible causal factors. There are so many “maybe’s” and words like “plausible” and “presumably” in this article to have confidence in the conjectured causalities. No sense changing diet based on associational relationships alone. So many possible paradoxical effects to account for first.

  • Jonathan Ray

    Avoiding normal dietary choline would be going far beyond what the evidence in the cited studies can yet support.

  • Green Kolibri

    Dear Dr.Greger, thank you so much for all your interesting lectures and presentations. I enjoyed one at the SF Vegetarian Festival a week ago.
    Recently I came across this article where the author suggests (like some people were predicting that the reaction from those, who don’t want to part with animal products, and the industry, of course would be like it) that it might be factory farming toxins that are to blame for the TMAO producing bacteria not the meat and animal products themselves”.
    Since the body can be cleaned from any bacteria with the help of antibiotics, and it takes only 2 weeks to restore the intestinal flora – then it seems that it should not be difficult to check whether “clean” start with the “organic”, or non factory farm animal products would bring back the TMAO causing bacteria or not.

  • PQRider

    Dr, Greger,
    Would you please comment on the recent Mayo Clinic paper disagreeing with the conclusions of the Cleveland Clinic study.

  • RappFan

    You’ve pretty much demonized choline here without saying why the body needs choline, especially athletes who train heavily. While I’m not a vegan nor will I ever be one, I find your website helpful in balancing my diet and it has even led me to incorporate more veggies into it. Keep up the good work.

  • pb

    Is carnitine play a role in Huntington’s as a factor in mitochondrial transport ?

  • Gail Ann Shores

    Dr. Oz had a show on last week where he recommended CLA supplement of 1500 mg twice a day. I have bought at GNC and started taking now I read this article?? Should I discontinue?

    • Don Forrester MD

      Before following recommendations from TV shows such as Dr. Oz I would check out more reliable free websites such as NutritionFacts or Dr. John McDougall. I have not seen any credible science which shows that recommending for the general population to take CLA at 1500 mg twice a day is beneficial.

    • Dr. Connie Sanchez, ND

      Evidence from randomized controlled trials (RCT), do not convincingly show that CLA intake produces clinically relevant effects on long-term body composition. (1) Moreover, there is some concern that taking conjugated linoleic acid may worsen diabetes.

      Martha Belury and her Ohio State research team
      “found that CLA supplementation significantly decreased body fat in the first group of mice, but at the same time excessive amounts of fat accumulated in the animals’ livers. Belury linked this accumulation of fat in the liver to increased insulin resistance.” (2)

      A healthy lifestyle and a whole food plant-based diet along with exercise is the only proven method for long-term weight loss and weight maintenance.


  • Gail Ann Shores

    Thank you Dr. Forrester and Dr. Sanchez for responding to me and so quickly!!

  • Max

    Would this include supplementary CDP-Choline (aka citicoline)?

  • Jerry Taylor

    is honey an animal protein and does it raise TMAO?

  • The Hearty Vegan

    This article made my Vegan Best of 2013 list! Thanks for all your research and expertise!

  • johnnywhite

    The gorilla in the room is “Probiotics”–these products mite change the entire “chemistry” of TMAO in the gut.

  • Buns

    This is all bad news for me. I eschew meat but take carnitine supplements because I have heart failure that entails a significantly enlarged heart. The carnitine has allowed me to go about normal everyday activities without having to stop to catch my breath and without pooling of blood in my feet. Are there any alternatives that would provide the same coronary benefits as the carnitine supplements?

  • Harald Illeditsch

    So what’s the deal with lecithin? Is it good or bad? And is there a difference between soy lecithin and sunflower lecithin?

  • Headache

    Thank you. Being a descendant of early American settlers, I now know it was not my ancestors that killed off the natives, it was the natives high meat consumption! :)

  • Achim

    I have two questions:
    1) the lecithin in eggs and TMAO – what about eating egg white only?
    2) avoiding Lecithin supplements: soy protein shakes do include Lecithin. Is this critical or is the dose so small that it does not really matter?

  • Achim

    Should read as
    1) Cholin in eggs and TMAO – what about eating egg white only?

  • cyndishisara

    Now this video obviously answers my question can we safely consume eggs by adding flax and or/ garlic. However, choline is so prevalent in the vegetable kingdom that it is impossible to avoid. Even with broccoli a pound (180 mg) the concentration is higher than 2 eggs as two eggs. Furthermore, betaine and choline are protective in control of homocysteine levels. This situation as it seems makes it hard to eat healthily. I do comprehend that vegans can handle a steak because their gut flora has already been transformed to non choline-phil. What about an occasional egg after our transformation? I sound like an egg glutton! Seriously, I have nothing against veganism however most of the world especially in colder climates consume a small percentage of their diet animal products.

  • Martin Van Lear

    this video is superb. my first thought was about phosphatidylserine (made from cow brains and soy beans) is sold in supplemental form to those with memory problems and to increase athletic performance. however, this research discusses phosphatidylcholine. yet when i researched the similarity between these two, it seems phophatidylcholine comes from the sames sources…i wonder if phosphatidylserine is bad for us as well??? gasp! anyone have any research or thoughts on this….if so please do share…thanks so much again dr. greger for this great presentation…

  • abstract

    Since Choline is a nutrient that is a precursor of the phosphatidylcholine and sphingomyelin, both major components of cell membranes and inadequate amounts can affect memory especially in an unborn developing fetus. What would you recommend as a suitable choline source?