The role and mechanism of action of bile acids in the digestive system - Bile acids in the gut

In the small bowel, the principal role of bile acids is emulsification, and thus facilitation of the absorption of lipids as well as lipid-soluble vitamins. However, the physiological importance of this function is limited, since about 60-70% of the normal amount of lipids present in the intestinal content can be absorbed without the participation of bile acid. Bile acids affect intestinal epithelia] cells, mucosal nerve endings, and enzyme activity in the intestinal lumen due to their detergent properties. This can cause alterations in gut hormone release, especially of motilin and cholecystokinin. Consequently, bile acids influence pancreatic and gastric secretion as well as gastrointestinal and gallbladder motility. Recent studies indicate that bile acids can act through muscarinic and nuclear cell receptors. Thus it can be stated that bile acids exert multidirectional effects in the digestive system and are of interest not only to biochemists and physiologists, but also to clinicians (Adv Clin Exp Med 2008, 17, 1, 83-89).