What role do intestinal bacteria play in TMAO production for omnivores?

Intestinal bacteria play a significant role in the metabolism of various dietary components, particularly in the context of TMAO (trimethylamine N-oxide) production. Carnitine, which is found in red meat and certain dairy products, can be converted by specific gut bacteria into trimethylamine (TMA). Subsequently, TMA is absorbed into the bloodstream and further metabolized in the liver to form TMAO. This process is linked to an increased risk of atherosclerosis, as TMAO has been associated with cardiovascular diseases.

The involvement of gut microbiota in this conversion highlights the dual nature of these bacteria—while they can contribute to the production of proatherogenic compounds, they also help break down food for nutrient absorption. Still, their conversion of carnitine and certain other compounds into TMAO is of particular concern in omnivorous diets high in red meat and dairy.

This pathway explains why the answer focusing on the conversion of carnitine into proatherogenic TMAO is correct, emphasizing the role of intestinal bacteria in potentially promoting cardiovascular risks through their metabolic activities.