TMAO (or trimethylamine N-oxide) is a metabolite produced by gut bacteria. Briefly, nutrients such as phosphatidylcholine (also known as lecithin), choline, and L-carnitine are abundant in animal-derived products such as red meat, egg yolk and full-fat dairy products.

When consumed, these nutrients are processed by gut bacteria resulting in the release of various metabolites including TMA (trimethylamine) into the blood. TMA is then transported to the liver where it is converted into TMAO which has been shown to regulate various physiological processes involved in the development of atherosclerosis.

What dietary modification may help reduce an elevated TMAO? The composition of the diet can have a dramatic effect on the composition of the gut microbiome. Through dietary modifications, including the elimination of TMAO precursors, the gut bacteria may be altered and TMAO levels reduced. Foods commonly found in the Mediterranean diet such as cold-pressed olive oil, balsamic vinegar, and red wine are rich in the compound DMB (or 3,3-dimethyl-1-butanol), which has been shown to inhibit TMAO production.