Bile Acids & the Microbiome

Bile acids play key roles in gut metabolism, cell signalling, and microbiome composition.

While the liver is responsible for the production of primary bile acids, bacteria in the gut modify these compounds to increase their diversity and biological function, with over 70 secondary bile acids having been identified as of 2022.

The gut microbiome manipulates bile acids through deconjugation of the amino acids, glycine or taurine, dehydroxylation, dehydrogenation, and epimerization of the C-5 position to produce allo-bile acids and epimerisation of the hydroxyl groups to produce iso-bile acids. Recently it has been discovered that gut microbiome can reconjugate bile acids this gives rise to new class of BA compounds known as microbially conjugated bile acids (MCBA’s). Alterations in the chemistry of these secondary bile acids have been linked to several diseases, such as cirrhosis, inflammatory bowel disease and cancer. Little is known about the complex chemical diversity of the gut derived bile acids and the interplay with the microbiome.