carne_rojaL-carnitine, a chemical compound widely present in red meat (and also some energy drinks), alters the composition of gut microbiota, leading to a potentially increased risk of heart disease. A study carried out by researchers at Cleveland Clinic (United States) has shown that the change in the bacteria living in the digestive tract leads to an increase in a compound related to the development of arteriosclerosis (narrowing or obstruction of the arteries).

According to the study, the problem is actually even more serious, as L-carnitine also causes an increase in the bacteria that metabolises it, producing even greater amounts of the compound that causes arteriosclerosis – trimethylamine N-oxide (known as TMAO). This, in turn, may lead to cardiac or circulatory system conditions such as a heart attack or stroke.

The results have been published in the journal Nature Medicine and, for the first time, the focus of the research considered that the connection between eating red meat and cardiovascular disease may be explained through the activity of the bacteria found in the gut microbiota.

Study leader Dr Stanley Hazen explains, “the bacteria living in our digestive tract – the microbiota – are dictated by dietary patterns (what we eat). A diet high in L-carnitine shifts our gut microbe composition and generates an increase in the bacteria that “like” carnitine, which means that meat eaters are more susceptible to forming TMAO and its artery-clogging effects. Meanwhile, vegans and vegetarians have a significantly reduced capacity to synthesise TMAO from carnitine, which may explain the cardiovascular health benefits of these diets.”