From the Guidelines
Drawing TMAO levels is not recommended as a routine test for cardiovascular risk assessment due to inconsistent evidence and potential confounding factors, such as reduced kidney function, which can influence TMAO levels 1. When considering the value of drawing TMAO values, it's essential to weigh the potential benefits against the limitations and uncertainties surrounding its role in cardiovascular disease.
- TMAO is a metabolite produced by gut bacteria from certain dietary components, including L-carnitine and phosphatidylcholine found in meat products 1.
- Some studies have reported associations between elevated TMAO levels and increased cardiovascular disease risk, but these findings are not consistent across all research, with some animal experiments showing inconsistent results 1.
- Additionally, TMAO levels can be confounded by factors such as reduced kidney function, which can lead to elevated TMAO levels regardless of dietary intake 1.
- The relationship between TMAO and cardiovascular disease is further complicated by the presence of TMAO and its precursors in foods like fatty fish, which are associated with beneficial cardiometabolic outcomes 1.
- Given these complexities and the need for more definitive evidence, controlled-feeding trials in humans are necessary to elucidate the causal contributions of TMAO derived from meat products to cardiovascular disease risk 1. In clinical practice, a more prudent approach would be to focus on established cardiovascular risk factors and lifestyle modifications, such as a balanced diet and regular physical activity, rather than relying on TMAO testing 1.
From the Research
Value of Drawing TMAO Values
- TMAO (Trimethylamine N-oxide) levels have been associated with an increased risk of cardiovascular disease (CVD) and atherosclerotic cardiovascular disease (ASCVD) events 2, 3, 4, 5, 6
- Elevated plasma TMAO levels have been linked to increased carotid intima-media thickness (cIMT), a marker of early atherosclerosis, independently of established cardiovascular risk markers 2
- TMAO levels have also been associated with renal function, and impaired renal function may modify the relationship between TMAO and ASCVD risk 3
- The association between TMAO and CVD risk may be sex-related, with TMAO being more sensitive in diagnosing CVD in men than in women 4
- TMAO and its related metabolites, such as L-carnitine and acetyl-L-carnitine, have been associated with adverse outcomes in acute heart failure patients 5
- Drawing TMAO values may be useful in predicting cardiovascular risk and monitoring disease progression, particularly in individuals with impaired renal function or those at high risk of CVD 2, 3, 4, 5, 6
Clinical Implications
- Measuring TMAO levels may help identify individuals at high risk of CVD and ASCVD events, allowing for early intervention and prevention strategies 2, 3, 4, 5, 6
- TMAO levels may be used as a biomarker to monitor the effectiveness of lifestyle interventions and treatments aimed at reducing CVD risk 2
- The relationship between TMAO and renal function highlights the importance of considering kidney health in the management of CVD risk 3
Future Directions
- Further studies are needed to fully understand the mechanisms by which TMAO contributes to CVD risk and to explore the potential therapeutic applications of TMAO measurement and modification 2, 3, 4, 5, 6
- Research should focus on developing effective strategies for reducing TMAO levels and mitigating its harmful effects on cardiovascular health 2, 3, 4, 5, 6