SRA

To understand how different diets, the consumers’ gut microbiota, and the enteric nervous system (ENS) interact to regulate gut motility, we developed a gnotobiotic mouse model that mimics short-term dietary changes that happen when humans are traveling to places with different culinary traditions. Studying animals transplanted with the microbiota from humans representing each cuisine and fed a sequence of diets representing those of all donors, we find that correlations between bacterial species abundances and transit times are diet dependent. However, the levels of unconjugated bile acids — reflecting microbial bile salt hydrolase activity — correlate with faster transit across diets, including a Bangladeshi diet. Mice harboring a consortium of sequenced bacterial strains from the Bangladeshi donor’s microbiota and fed a Bangladeshi diet revealed that the commonly used spice, turmeric, slows transit times. Turmeric affects gut motility via bacterial bile acid deconjugation and modulation of Ret signaling in the ENS. These results demonstrate how a single food ingredient interacts with a functional microbiota trait to regulate host physiology.