High Levels of The gbuA Gene Associated with a Diet Rich in Red Meat and High Levels of TMAO

Cardiovascular diseases are a leading cause of death among women and men in the US. This term covers various types of pathologies, such as strokes, myocardial infarction, heart failure, and peripheral vascular disease. Factors that can explain its development are heredity, age, smoking, high blood pressure, sedentary lifestyle, high cholesterol, obesity, and poor diet. A team of researchers has just studied this last factor and, more specifically, the effect of red meat consumption on the body. According to the scientists in the study, people who eat red meat are more likely to suffer from cardiovascular disease. Their work was published in the journal Nature Microbiology.

TMAO increases the risk of cardiovascular disease

To understand what happens to our bodies when we eat red meat, we need to look at TMAO (Trimethylamine N-oxide ), a molecule produced by gut bacteria when they digest an amino acid derivative called “carnitine”, which is present in red meat. In previous research, scientists found that TMAO increases the risk of heart disease, blood clots, and stroke.

But how do gut microbes produce TMAO? With this new study, researchers have answered that question. They observed the two-step process by which gut bacteria convert carnitine into TMAO. Few bacteria in the gut are able to convert this amino acid to TMAO immediately. In a first step, gut microbes convert carnitine into a molecule called γBB (γ-Butyrobetaine). Next, a specific type of bacteria called Emergencia Timonensis converts the γBB molecule into TMAO.

Stool samples taken from study participants confirmed this observation. The introduction of Emergencia Timonensis promoted the conversion of carnitine to TMAO, thus increasing the TMAO levels of the patients. In addition, the study of blood tests of the 3,000 participants showed that those with high γBB levels had a higher risk of cardiovascular disease.

Reduced cardiovascular risk in vegetarians and vegans

The researchers were able to identify four genes (gbuA, gbuB, gbuC and gbuE) that are essential for the conversion of γBB to TMAO. According to the researchers, high blood levels of gbuA are associated with a diet rich in red meat and high levels of TMAO. A meat-free diet would be associated with reduced levels of gbuA gut microbes. The scientists noted that vegetarians and vegans had little or no ability to convert carnitine to TMAO and, therefore, had lower cardiovascular risk.

In conclusion, the authors believe that reducing red meat consumption may reduce the risk of cardiovascular disease. In the long term, the discovery of this process of converting carnitine to TMAO could enable the development of new, more targeted therapies.