Link Between Heart Disease and Carnitine
Carnitine, abundant in red meat and added as a supplement to popular energy drinks has been found to promote atherosclerosis -- or the hardening or clogging of the arteries.
Prior research has shown that a diet with frequent red meat consumption is associated with increased cardiovascular disease risk, but that the cholesterol and saturated fat content in red meat does not appear to be enough to explain the increased cardiovascular risks. This discrepancy has been attributed to genetic differences, a high salt diet that is often associated with red meat consumption, and even possibly the cooking process, among other explanations.
Carnitine and Fatty Deposits
The research by the Cleveland Clinic shows that bacteria living in the human digestive tract metabolize the compound carnitine, turning it into trimethylamine-N-oxide (TMAO).
TMAO is strongly linked with the build-up of fatty deposits in blood vessels, which can lead to heart disease and death.
Further, the research finds that a diet high in carnitine promotes the growth of the bacteria that metabolize carnitine, compounding the problem by producing even more of the artery-clogging TMAO.
Cardiovascular Health Benefits of Vegan, Vegetarian Diets
Meanwhile, vegans and vegetarians have a significantly reduced capacity to synthesize TMAO from carnitine, which may explain the cardiovascular health benefits of these diets.
Caution with Carnitine Supplements
Carnitine is not an essential nutrient; our body naturally produces all we need, but it is also a dietary supplement available in pill form and a common ingredient in energy drinks. With this new research in mind, the researchers cautions there may be a risk to people taking carnitine supplements
The above story is based on the April 7, 2013 news release by Cleveland Clinic.
The research has been published online in the journal Nature Medicine:
Koeth RA et al. Intestinal microbiota metabolism of l-carnitine, a nutrient in red meat, promotes atherosclerosis. Nat Med, 2013; DOI: 10.1038/nm.3145