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Unexpected heart disease culprit found in red meat and supplements

Kathleen Blanchard's picture
A new culprit found for heart disease from red meat and dietary supplements

Red meat that is high in saturated fat is supposedly known to promote heart disease. Have you questioned the role of saturated fat for heart disease? Interestingly, hardening of the arteries or atherosclerosis that leads to stroke, heart attack and other vascular diseases may come from how a compound abundant in red meat that is also taken as popular dietary supplement is metabolized. The newest and unexpected culprit for heart disease may be carnitine versus fat, grilled meat or other suggested culprits.

Carnitine metabolizes in the gut based on diet to promote heart disease

The compound carnitine that is taken as a dietary supplement, added to energy drinks and is abundant in red meat was found by researchers to promote fatty plaque in the arteries, according to study results published in Nature Medicine - but only for meat eaters.

Stanley Hazen, M.D., Ph.D., Vice Chair of Translational Research for the Lerner Research Institute and section head of Preventive Cardiology & Rehabilitation in the Miller Family Heart and Vascular Institute at Cleveland Clinic, and Robert Koeth, a medical student at the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University who conducted the study found live bacteria in the human gut turn carnitine into trimethylamine-N-oxide (TMAO).

For their study, they tested carnitine and TMAO levels of meat eaters, vegans and vegetarians and then analyzed data from 2,595 patients electively undergoing cardiac screening.

The researchers also compared normal mice given a carnitine rich diet to mice with low levels of gut bacteria given the same diet.

The finding revealed TMAO restricts cholesterol metabolism to explain how it promotes removal of cholesterol.

What else does carnitine do?

The compound is manufactured in the body and is important for converting fat into energy. Carnitine is stored in the skeletal muscles, brain, sperm and heart. It is produced in the liver and kidneys. Healthy people make enough carnitine for optimal health.

Supplements have been proposed to improve athletic performance.erectile dysfunction and heart conditions, but studies are not conclusive that they provide any benefit.

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In addition to red med, the compound is mainly found in fish, asparagus, wheat, avocados and peanut butter.

Diet affects TMAO levels and thus heart risks

Patients with high carnitine and TMAO levels were more prone to heart attack, stroke and death. Vegans and vegetarians had much lower levels of TMAO.

Another interesting finding is the discovery that certain gut microbes seem to influence who might get heart disease - but so does diet.

In the study, carnitine boosted TMAO levels for meat eaters, but not for vegans and vegetarians.

Hazen says what we eat over a long period of time affects bacteria living in the gut. Meat eaters have a higher chance of heart disease because their gut bacteria produces higher levels of TMAO that promotes clogged arteries.

A vegetarian diet may lower the chances of heart disease because vegetarian guts can't synthesize TMAO from carnitine that is not just in meat, supplements and drinks. It is occurs naturally in the body.

Hazen said the new research suggests a new and different connection between heart disease and red meat. It may not be the saturated fat, salt added to meat, the cooking process or even additives that have all been suggested to this point.

Carnitine metabolism could be the answer to how red meat promotes heart disease, the researcher suggests, that is different in everyone.

Hazen and his team have been studying the role of gut microbes and their role in atherosclerosis that goes beyond the role of genes. Hazen says the new study means a closer look should be taken at carnitine supplements that might be fostering heart disease for some individuals. The finding also supports the heart healthy benefits of a plant based diet. Have you considered making a dietary change for the sake of your own heart?

Cleveland Clinic
April 7, 2013

Image credit: Morguefile



This is an interesting finding concerning carnitine. As a long-time vegan, I was not aware I had lower levels of TMAO. Thanks for sharing this study!
You're welcome Deborah. I found it very interesting too.