Inulin does not affect trimethylamine N-oxide formation in mice with a high-fat diet combined with choline and L-carnitine

Emerging evidence suggests that gut bacteria-derived trimethylamine N-oxide (TMAO) elevates the risk of cardiovascular disease, and dietary fiber holds the potential to attenuate TMAO formation. However, the effectiveness of dietary fiber, such as inulin, in inhibiting TMAO formation remains controversial. Therefore, this study investigated the effect of inulin supplementation on TMAO formation in mice with high TMAO levels induced by a high-fat diet (HFD) combined with choline and L-carnitine. Results showed that HFD treatment significantly elevated blood TMAO concentrations and increased the abundances of TMAO formation-associated gut bacteria, as well as the abundances of functional genes responsible for TMA formation. While the supplementation of choline and L-carnitine greatly enhanced blood trimethylamine (TMA) and TMAO levels, inulin supplementation did not significantly affect TMAO levels and had limited impact on TMA-associated gut bacteria, except for Desulfitobacterium hafniense .