RESEARCH conducted at the Cleveland Clinic's Lerner Research Institute has pinpointed carnitine for playing a role in the development of cardiovascular disease.
Carnitine is a compound found in energy drinks, nuts, beans, produce and red meat and also is sold as a dietary supplement. Carnitine commonly helps the body transport fatty acids into cells to be used as energy. However, the researchers found that, in both humans and mice, bacteria in the digestive tract can convert carnitine into a metabolite called TMAO that promotes atherosclerosis.
The research was published April 8 in the journal Nature Medicine.
The researchers examined the records of 2,595 meat eaters and vegetarians undergoing cardiac evaluations and found that patients with high levels of TMAO were more likely to develop cardiovascular disease and suffer heart attacks, strokes and death.
Dr. Stanley Hazen, chief of cellular and molecular medicine at Lerner, said carnitine may be compounding the negative effects of the cholesterol and saturated fat found in beef, pork and other red meat.
However, Dr. Betsy Booren, chief scientist at the American Meat Institute, noted that cardiovascular disease is "a complex condition" that's associated with a number of factors, from genetics to lifestyle, and attempts to link it to "a single compound found at safe levels in red meat oversimplifies" the issue.
Many other studies examining carnitine have not shown adverse effects at a number of doses, she said, adding that a fact sheet from the National Institutes of Health concludes that carnitine is essential and safe.
In fact, Hazen said some energy drinks contain more carnitine than a large steak.
Duffy MacKay, vice president for regulatory and scientific affairs at the Council for Responsible Nutrition, which represents energy drink and supplement makers, suggested that the Lerner researchers drew "large conclusions from small studies" of humans and mice and said the concept that just one compound in the diet could be responsible for cardiovascular disease "is questionable."
The NIH fact sheet is available at www.ods.od.nih.gov/factsheets/Carnitine-HealthProfessional.