In a recently published medical study conducted by the National Heart, Lung, and Blood Institute (NHLBI), researchers identified another reason to limit red meat consumption: high levels of a gut-generated chemical called trimethylamine N-oxide (TMAO) that also is linked to heart disease. Scientists found that people who eat a diet rich in red meat have triple the TMAO levels of those who eat a diet rich in either white meat or mostly plant-based proteins, but discontinuation of red meat eventually lowers those TMAO levels.
This is especially troubling for African-American men who consume quite a bit of red meat as part of their diets. Red meat includes ground beef, steaks, roasts, and the ever dangerous processed (cold cuts) and cured meats. The NHLBI study emphasizes the need for African-Americans to reconsider how much red meat they consume and its link to heart disease, which is the leading cause of death for black people in the U.S.
TMAO is a dietary byproduct that is formed by gut bacteria during digestion and is derived in part from nutrients that are abundant in red meat. While high saturated fat levels in red meat have long been known to contribute to heart disease -- the leading cause of death in the United States -- a growing number of studies have identified TMAO as another culprit. Until now, researchers knew little about how typical dietary patterns influence TMAO production or elimination.
"These findings reinforce current dietary recommendations that encourage all ages to follow a heart-healthy eating plan that limits red meat," said Charlotte Pratt, Ph.D., the NHLBI project officer for the study and a nutrition researcher and Deputy Chief of the Clinical Applications & Prevention Branch, Division of Cardiovascular Sciences, NHLBI. "This means eating a variety of foods, including more vegetables, fruits, whole grains, low-fat dairy foods, and plant-based protein sources such as beans and peas."
Stanley L. Hazen, M.D., Ph.D., senior author of the study and section head of Preventive Cardiology & Rehabilitation at the Cleveland Clinic estimated that as many as a quarter of middle-aged Americans have naturally elevated TMAO levels, which are made worse by chronic red meat consumption. However, every person's TMAO profile appears to be different, so tracking this chemical marker, Hazen suggested, could be an important step in using personalized medicine to fight heart disease.
For African-Americans, the consumption of red meat is even more problematic when considering other health issues we often face. Hypertension (high blood pressure) and obesity, coupled with a diet heavy in red meat, pork, and saturated fats are a recipe for an unhealthy body and could lead to heart attacks, stroke, kidney failure, and other ailments..
Importantly, the researchers discovered that the TMAO increases were reversible. When the test subjects discontinued their red meat diet and moved to either a white meat or non-meat diet for another month, their TMAO levels decreased significantly.