Many studies are moving beyond investigation of species that are present in the gut, and addressing how the gut microbiota function. How do they achieve, for example, their influence on weight?
Irish researchers found that microbial bile salt hydrolase (BSH) activity changed functions in the host, both in the gastrointestinal tract and in the liver. In mice, gastrointestinal expression of BSH led to local bile acid deconjugation, and thus, the mice exhibited changes in lipid and cholesterol metabolism, signaling functions, and weight gain. Higher levels of BSH seemed to influence mediators of cholesterol homeostasis, gut homeostasis and circadian rhythm.
Authors say this work on the mechanisms by which microbiota influence metabolism may inform the development of probiotic products that target obesity.
Joyce SA, et al. (2015) Bacterial bile salt hydrolase in host metabolism: Potential for influencing gastrointestinal microbe-host crosstalk. Gut Microbes DOI:10.4161/19490976.2014.969986