TMAO (Trimethylamine N-oxide)

TMAO is a substance produced when gut bacteria break down certain foods—especially red meat, eggs, and some fish—and your liver processes the byproduct. Research has found that people with higher TMAO levels in their blood tend to have a greater risk of heart disease and related events. Your TMAO level can be influenced by what you eat, the types of bacteria living in your gut, and how well your kidneys are working. A higher level may be a signal to discuss your diet and overall heart health with your healthcare provider. This test is one piece of the puzzle and is most useful when considered alongside your other health information.

When elevated: Elevated TMAO levels have been associated with increased risk of atherosclerotic cardiovascular disease, major adverse cardiovascular events, thrombotic risk, and all-cause mortality. High levels may also reflect impaired renal clearance, a gut microbiome profile favoring TMA-producing bacteria, or high intake of choline- and carnitine-rich foods. When low: Low or undetectable TMAO levels are generally considered favorable from a cardiovascular risk perspective. Low levels may reflect a plant-predominant diet, a gut microbiome composition with reduced TMA-producing bacteria, or adequate renal function facilitating normal clearance dynamics.

TMAO is not a primary performance or training-specific marker. However, it may be relevant for athletes interested in cardiovascular health and longevity, since elevated TMAO associates with atherosclerosis risk independent of traditional factors like cholesterol. Active individuals consuming high amounts of red meat or eggs for protein should be aware that TMAO levels reflect both diet composition and gut microbiome health—factors modifiable through dietary pattern shifts and potentially probiotic approaches.