From the Guidelines
Elevated Trimethylamine N-oxide (TMAO) levels are clinically significant as they are associated with increased risk of cardiovascular disease, according to a 2022 study published in Cell Host and Microbe 1. TMAO is produced when gut bacteria metabolize certain dietary components like choline, phosphatidylcholine, and L-carnitine, which are abundant in red meat, egg yolks, and dairy products. Some key points to consider about TMAO include:
- Normal TMAO levels are typically below 6 μmol/L, with higher levels correlating with greater cardiovascular risk.
- The production of TMAO is influenced by the gut microbiome, with certain bacteria contributing to its formation 1.
- Dietary modifications are the primary intervention for patients with elevated TMAO, including reducing red meat and egg consumption while increasing plant-based foods, fiber, and foods with natural TMAO inhibitors like extra virgin olive oil and resveratrol-containing foods.
- Probiotics and prebiotics may help by altering gut microbiota composition, although more research is needed to confirm their effectiveness.
- Regular monitoring of TMAO levels is recommended for high-risk patients, especially those with existing cardiovascular disease, diabetes, or chronic kidney disease, as suggested by the study 1. TMAO appears to promote atherosclerosis by enhancing cholesterol accumulation in macrophages, promoting platelet hyperreactivity, and increasing inflammatory responses in vascular cells, making it both a biomarker and potential causal factor in cardiovascular pathology. The clinical significance of TMAO is further supported by its association with other health outcomes, such as colorectal cancer, although more research is needed to fully understand its role in these diseases 1.
From the Research
Clinical Significance of TMAO Lab Results
The clinical significance of Trimethylamine N-oxide (TMAO) lab results is a topic of interest in the medical field, particularly in relation to cardiovascular disease.
- TMAO levels have been found to predict cardiovascular disease (CVD) risk, possibly by impacting cholesterol metabolism and oxidative stress 2.
- Elevated plasma TMAO levels have been associated with increased risk of major adverse cardiovascular events, such as death, myocardial infarction, or stroke 3.
- TMAO levels have also been linked to other diseases, including kidney failure, diabetes, and cancer 3.
Association with Cardiovascular Disease
Studies have shown that TMAO levels are positively associated with carotid intima-media thickness (cIMT), a marker of early atherosclerosis 2.
- Higher TMAO levels have been found to predict increased cIMT, independently of age, sex, and visceral fat mass 2.
- The decrease of cIMT during a lifestyle intervention may be related to the decrease of TMAO levels 2.
- Statin therapy has been shown to decrease plasma TMAO levels, suggesting a potential contribution to cardiovascular benefits 4.
Predictive Value of TMAO
TMAO levels have been found to predict future risk of coronary artery disease in apparently healthy individuals 5.
- Elevated TMAO levels have been associated with higher mortality in patients with chronic kidney disease, peripheral artery disease, type 2 diabetes, and heart failure 6.
- TMAO levels could potentially be integrated into existing risk stratification tools to lead to novel prevention and treatment approaches to cardiovascular disease 6.
Key Findings
- TMAO levels are associated with increased risk of cardiovascular disease and mortality 2, 3, 6.
- Statin therapy decreases plasma TMAO levels, suggesting a potential contribution to cardiovascular benefits 4.
- TMAO levels predict future risk of coronary artery disease in apparently healthy individuals 5.