Trimethylamine N-oxide (TMAO), choline and betaine serum levels have been associated with metabolic diseases including type 2 diabetes (T2D) and non-alcoholic fatty liver disease (NAFLD). These associations could be mediated by insulin resistance.
However, the relationships among these metabolites, insulin resistance and NAFLD have not been thoroughly investigated. Moreover, it has recently been suggested that TMAO could play a role in NAFLD by altering bile acid metabolism. The authors conclude, that in obese subjects, circulating TMAO levels were associated with NASH mainly in the presence of T2D.
Functional studies are required to evaluate the role of insulin resistance and T2D in this association, both highly prevalent in NASH patients.