Bad news for steak and energy-drink lovers: A new study published in Nature Medicine finds they share a common ingredient that leads to heart disease, the Wall Street Journal reports. Carnitine, a compound that helps the body metabolize fatty acids, is plentiful in red meat and is often found in energy drinks and dietary supplements. Researchers believe that bodies may be converting carnitine into TMAO, a compound that can thicken the walls of arteries. They found that the more TMAO in a person's bloodstream, the more likely they were to suffer heart disease, a heart attack, stroke, and death.
This doesn't mean that fat and cholesterol—the culprits traditionally blamed for the increased risk of heart disease with red meat—are off the hook, just that carnitine may be compounding the problem. "Cholesterol is still needed to clog the arteries, but TMAO changes how cholesterol is metabolized—like the dimmer on a light switch," said the study's lead researcher. But a scientist in the supplement and energy drink industry questions the results, saying it's "questionable" whether "one component of your diet, or one molecule, is responsible for your health woes."