Red Meat Is Bad For Your Heart, But Possibly For A Previously Unknown Reason

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[Source: Wikipedia]

[Source: Wikipedia]

You knew that too much red meat wasn’t good for you, but maybe you didn’t know the whole story.

High in saturated fat and dripping cholesterol, many a meat lover has either accepted the risk for heart disease and continued to mow down or heartbreakingly changed their ways. A new study adds another sour ingredient to the recipe. It’s been known that carnitine helps to transport fatty acids into cells where they can be metabolized for energy. But a recent study has shown that the normally do-good carnitine can be made to do bad things for the heart.  And red meat is full of carnitine.

Previous research has shown that carnitine can be converted by microbes in the gut to the substance trimethylamine-N-oxide, or TMAO, which causes atherosclerosis, or hardening of the arteries. Atherosclerosis can lead to heart attack, stroke, and death.

To gauge the effects of carnitine in the diet, the study measured both the intake of carnitine and the levels of TMAO in the blood, and checked for associated risk for cardiovascular disease. It involved 2,595 patients under evaluation for heart-related conditions. Based on their diets, the patients were divided into three groups: omnivores, vegans and vegetarians. They found that diets high in carnitine showed a higher risk for heart attack, stroke and death, but only when those diets were accompanied by high levels of TMAO.

New study shows carnitine, found in many dietary supplements, raises the risk of cardiovascular disease. [Source: Wikipedia]

New study shows carnitine, found in many dietary supplements, raises the risk of cardiovascular disease. [Source: Wikipedia]

Baseline levels of TMAO were higher in omnivores than in vegans and vegetarians. And even when they gave vegans and vegetarians doses of carnitine, their bodies produced lower amounts of TMAO compared to their meat eating counterparts.

The reason for the difference appears to lie in the different profiles of gut bacteria. “The bacteria living in our digestive tracts are dicated by our long-term dietary patterns,” Stanley Hazen, chief of cellular and molecular medicine at the Cleveland Clinic’s Lerner Research Institute and lead author of the study, said in a press release. “A diet high in carnitine actually shifts our gut microbe composition to those that like carnitine, making meat eaters even more susceptible to forming TMAO and its artery-clogging effects. Meanwhile, vegans and vegetarians have a signficantly reduced capacity to synthesize TMAO from carnitine, which may explain the cardiovascular health benefits of these diets.”

In a separate experiment, the researchers gave food to mice supplemented with carnitine. They saw TMAO levels spike and the risk for atherosclerosis in the mice doubled.

We’ve always been told that reducing our intake of saturated fat reduces the risk for cardiovascular disease, but a study performed in 2010 turned that idea on its head. Amazingly, the meta-analysis that included data from 347,747 subjects found no link between the amount of saturated fat a person ate and risk for cardiovascular disease.

And while carnitine is not an essential nutrient – our bodies produce enough of it – it is found in a number of dietary supplements used to build muscle and boost energy. Because of the widespread use of these products, Hazen argues, research into a possible link between carnitine supplements and cardiovascular disease is something that needs to be studied more.

So, in the end, the message remains the same, even if it’s not the saturated fat we need to worry about, but the carnitine. Nothing changes for the omnivores, vegans and vegetarians out there. That is, unless the more health-minded are bolstering their performance with protein shakes and energy drinks.

Discussion — 13 Responses

  • Improbus Liber April 11, 2013 on 10:33 am

    Time to become a vegan? Is this just red meat? How about chicken, pork, fish or insects?

    • Vector Improbus Liber April 11, 2013 on 4:53 pm

      I’m not sure if you’ve already noticed, but near the bottom of the wiki page provided in the article was some of your answer. http://en.wikipedia.org/wiki/Carnitine#Food

      • Improbus Liber Vector April 12, 2013 on 10:10 am

        That is a handy wiki page. Thanks! I noticed that insects weren’t on the list but I imagine they would be around or below chicken. I don’t actually eat insects but I wouldn’t be averse to trying them.

        • Richard Lewis Improbus Liber April 15, 2013 on 6:54 am

          The real issue is that meat production is about 10 times less efficient than the production of plant crops.

          You will smug people in some countries laugh this off….many of our fellow brothers and sisters elsewhere are starving,,,,,what a world we live in hey

  • Vector April 11, 2013 on 4:50 pm

    “A diet high in carnitine actually shifts our gut microbe composition to those that like carnitine, making meat eaters even more susceptible to forming TMAO and its artery-clogging effects. Meanwhile, vegans and vegetarians have a signficantly reduced capacity to synthesize TMAO from carnitine, which may explain the cardiovascular health benefits of these diets.”

    In other words, moderation or elimination are the keys to good health. A little less touched on note is that your body cleans and repairs itself when you give it exactly what it needs. Also for good heart health, take adequate portions of Omega-3. Also drink adequate water, often breath deeply, take things like Vitamin C, D, E, Iodine, and other things which boost your immune system and regulate your metabolism. Vitamin C is also important for heart health because it aids in the synthesis of collagen, which keeps your blood vessels more elastic.

    A healthy immune system is important because it, among other things, helps eliminate artery plaque by sending phagocytes to consume the plaque as useless matter. You must also stretch your body and perform aerobics practically everyday to facilitate the movement of lymph (immune system juice) throughout your lymphatic system (primary immune center) and entire body.

  • Dave Sill April 12, 2013 on 6:18 am

    http://chriskresser.com/red-meat-and-tmao-its-the-gut-not-the-meat

    “The mistaken blame of saturated fat and cholesterol as drivers of heart disease led to a decades-long campaign to encourage low-fat, high-carbohydrate diets. Unfortunately, the effects of this campaign were not harmless. Not only did it unnecessarily deprive people of nutrient-dense, nourishing (and delicious!) foods like meat, butter and eggs, it may have indirectly contributed to the epidemics of obesity, heart disease and diabetes. Studies have shown that when people replace saturated fat with carbohydrates, the risk of heart disease doesn’t go down—it goes up. (1) This is not because of the carbohydrates, per se, but because 85% of the grain consumed in the U.S. is in the highly refined form. (2)”

    • Ryan Dave Sill April 19, 2013 on 9:59 am

      Yep, and notice they studied omnivores, vegans, and vegetarians… but no carnivores… or anyone on a high fat, very low carb diet.

  • Phil G April 12, 2013 on 2:40 pm

    Maybe time to stop taking carnitine supplements…

  • Richard Lewis April 15, 2013 on 6:54 am

    The real issue is that meat production is about 10 times less efficient than the production of plant crops.

    You will smug people in some countries laugh this off….many of our fellow brothers and sisters elsewhere are starving,,,,,what a world we live in hey

  • jg April 16, 2013 on 2:16 pm

    I have to say…I just don’t what to eat. I simply can’t stomach vegetables for the most part. Raw tomatoes and carrots, sure…that’s about it. Wheat, corn, and rice have all been GMO’d to death and are arguably bad for you anyway. Now steak is out, and I have no doubt chicken, pork, and fish aren’t far behind. The all fruit diet has….noxious effects…and corporate america won’t let me subsist on the beer-only diet.

    What’s left????

  • Grimjoe April 18, 2013 on 3:06 am

    Saw a study once called the okinowans where there results said that anything that has been consumed for 2 generations(parents and grandparents) is good for you(generalised) of coarse that doesnt take into account chemical additives or growth steroids.

  • robit April 19, 2013 on 2:23 am

    As a new poster, I am not sure if linking is limited, but I’ll chance this. Dr. Hazen had a good interview on NPR. Here is a link to the transcript:
    http://www.wbur.org/npr/177029247/red-meats-heart-risk-goes-beyond-the-fat
    I have over the last few months become aware that the hyperbole of there being a connection between saturated fat and heart diesase is wrong. Fact is, it is the carbohydrates that are the problem. This study sure adds an important new factor to be considered. Sounds like the Canadian Aboriginal peoples knew something when they ate the organs and fat of their game and gave the lean meat to their dogs. Eh? Is there a way to reduce the TMAO producing bacteria other than cutting down on the ingestion of carnatine?

  • Zippy April 23, 2013 on 2:57 pm

    Mmmmmm, carnitine.