According to the Center for Disease Control (CDC), “heart disease is the leading cause of death for men, women, and people of most racial and ethnic groups in the United States.” In fact, in the United States, one person dies every 37 seconds due to cardiovascular disease. In an unsettling statistic, approximately 75% of the deaths in the United States are attributed to heart disease.
Many people believe that eating too much red meat and eggs can put you at a higher risk of cardiovascular disease and heart attacks. This adage arose from the belief, by many researchers, that a molecule called trimethylamine-N-oxide (TMAO), can clog up arteries, leading to devastating heart problems like heart attacks and strokes. TMAO is a metabolite—a byproduct of the metabolism of choline by the bacteria in your gut—produced in the body when choline-rich foods such as red meats and eggs are consumed. A review published in 2019 reported that higher levels of TMAO could be linked to not only cardiovascular disease but early death in general. However, Prof. John O’Sullivan, head of the Heart Research Institute’s (HRI) Cardiometabolic Disease Group, says, “the scientific literature has not been able to replicate the original studies” that show that “that high circulating levels of TMAO leads to thickened arteries, sticky blood, heart attack, and stroke.”
In a new study published in the European Society of Cardiology journal, Cardiovascular Research claims to have debunked the theory that red meat is connected to heart disease. Prof O’Sullivan, who was the corresponding author of the study, says, “we’ve discovered that contrary to other research, this metabolite called TMAO, isn’t actually responsible for these common debilitating heart conditions.” The study found that changes in the gut’s microbiome due to different diets, i.e., either red meat-rich diets or high fiber diets, both showed an increase in TMAO production. They conclude that “the gut itself is a site of significant oxidative production of TMAO.” The Heart Research Institute team also performed an analysis of a large sample size of both rats and humans and found no “no direct association of plasma TMAO and the extent of atherosclerosis.” However, they did find that high-levels of TMAO is an indicator of atherosclerotic plaque instability. Thus, they conclude that high levels of TMAO in patients is still a useful marker of cardiovascular risk.