Dietary interventions alter the formation of the disease-associated metabolite, trimethylamine (TMA), via intestinal microbial TMA lyase activity. Nevertheless, the mechanisms regulating microbial enzyme production are still unclear. Sequencing of the gut bacteria 16S rDNA demonstrated that dietary intervention changed the composition of the gut microbiota and the functional metagenome involved in the choline utilization pathway. Characterization of the functional profile of the metagenomes and metabonomics analysis revealed that a series of Kyoto Encyclopedia of Genes and Genomes orthologous groups and enzyme groups related to accumulation of methylglyoxal (MG) and glycine were enriched in red meat diet-fed animals, whereas fiber-rich diet suppressed glycine formation via the MG-dependent pathway. Our observations suggest associations between choline-TMA lyase expression and MG formation, which are indicative of a novel role of the gut microbiota in choline metabolism and highlight it as a potential target for inhibiting TMA production.
Keywords: dietary fiber; glycyl radical enzyme; methylglyoxal; microbial conversion; trimethylamine.