Eating plant-based meat alternatives instead of red meat can improve some cardiovascular risk factors, according to a new study by researchers at Stanford Medicine that was published in the American Journal of Clinical Nutrition today.
While it may seem obvious that a patty made of plants is a healthier option than a hamburger, many of the new meat alternatives have relatively high levels of saturated fat and added sodium.
"There's been this sort of backlash against these new meat alternatives," senior author Christopher Gardner explained. "The question is, if you're adding sodium and coconut oil, which is high in saturated fat, and using processed ingredients, is the product still actually healthy?" To find out, Gardner and his team gathered a group of more than 30 individuals and assigned them to two different diets, each one for eight weeks. One diet called for at least two daily servings of meat—the options available were primarily red meat—and one called for at least two daily servings of plant-based meat.
The researchers then measured blood cholesterol, blood pressure, weight, and the levels of a molecule, trimethylamine N-oxide, or TMAO, in the body; TMAO has been linked to cardiovascular disease risk. They found that TMAO levels were lower when study participants were eating plant-based meat.
Gardner calls TMAO "an emerging risk factor," meaning there seems to be a connection between higher levels of TMAO and an increased risk of cardiovascular disease, but the connection has yet to be definitively proved. Two precursors to TMAO, carnitine and choline, are found in red meat, so it's possible that individuals who regularly eat beef, pork or lamb for dinner will simply have higher levels of TMAO.
"At this point we cannot be sure that TMAO is a causal risk factor or just an association," Gardner said. However, he sees a reason to pay attention to TMAO readouts. In the past few years, studies have shown that high levels of TMAO are consistent with increased inflammation and blood clotting, among other health concerns. Gardner points to another study in which researchers found that people with elevated TMAO had a 60% higher risk for adverse cardiovascular events, such as a heart attack.