It seems that the role of Bile acids is not only for fat absorption but they play a very important role on the regulation of immunity. I hope researchers investigate Bile acids as soon as possible.
https://www.genengnews.com/news/bile-acid-metabolites-keep-the-guts-t-cells-in-good-humor/ Bile Acid Metabolites Keep the Gut’s T Cells in Good Humor https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6099188/ Bile Acids Activated Receptors Regulate Innate Immunity https://huhlab.med.harvard.edu/rese...esponses-synthesis-small-molecule-metabolites https://www.researchgate.net/public...ts_gut_microbiota_and_hepatic_innate_immunity https://www.sciencedirect.com/science/article/pii/S1665268119310403 The Role of the Gut Microbiota in Bile Acid Metabolism https://www.nature.com/articles/s41385-019-0162-4.pdf?origin=ppub Emerging rules of bile acid in mucosal immunity and inflamation https://www.sciencedaily.com/releases/2020/01/200103141047.htm Bile acids may help regulate gut immunity and inflammation https://www.clinexprheumatol.org/article.asp?a=10878 https://www.rug.nl/research/portal/files/14290102/Chapter_8.pdf