You are here:

More evidence red meat may be bad for your heart

Photo: Thinkstock

A new study suggests frequent meat eaters should cut back on red meat—and should avoid L-carnitine supplements.

Think twice—or maybe three times—about taking L-carnitine supplements if you eat red meat.

L-carnitine is a popular supplement. It’s a common ingredient in energy drinks and is sold in pill form. In the body, L-carnitine from foods carries fuel to mitochondria—the tiny power plants inside cells. It’s not clear whether taking L-carnitine supplements improves this process; nor is there proof that these supplements offer other health benefits. Nevertheless, many people take them in hopes they will increase energy and athletic performance, fight mental decline, prevent a second heart attack, or even improve male sexual performance.

Many foods contain L-carnitine, but red meat is the richest food source. An elegant study in Nature Medicine now finds that people who eat meat—but not vegetarians—grow particular kinds of bacteria in their bowels. These gut bugs aren’t harmful by themselves. But when they take in L-carnitine, they produce trimethylamine-N-oxide (TMAO), a compound linked to—but not proven to cause—clogged arteries.

“Based on this study, I’d be concerned about taking L-carnitine supplements without a good reason,” says Dr. Dariush Mozaffarian, associate professor of medicine at Harvard-affiliated Brigham and Women’s Hospital. “There was no real reason to take it before the study, and now a well-done study suggests there may be harm. I think that definitely would make me think three times before taking an L-carnitine supplement.”

Mozaffarian notes that while the study implicates TMAO as a major player in atherosclerosis, much more needs to be learned.

“It’s too early to decide that this molecule, TMAO, causes atherosclerosis or that this is responsible for some of the associations of meat intake and risk,” he says.

Posted by: Dr.Health

Back to Top