Bile acids (BA)

Bile acids are steroid-based molecules synthesized from cholesterol in the liver and released into the small intestine to facilitate the digestion and absorption of dietary lipids and fat-soluble vitamins (Hofmann, 1999). They function as essential detergents and signaling molecules, activating key metabolic receptors like the Farnesoid X receptor (FXR) and TGR5 to maintain systemic lipid and glucose homeostasis (Chiang, 2009). In clinical practice, bile acids in the intestinal lumen serve as a therapeutic target for bile acid sequestrants, which are used to treat hypercholesterolemia and bile acid diarrhea (StatPearls, 2023). By binding bile acids and preventing their reabsorption, these drugs promote the fecal excretion of bile salts, prompting the liver to upregulate the conversion of cholesterol into new bile acids. This mechanism effectively reduces circulating LDL cholesterol levels and alleviates symptoms associated with bile acid malabsorption. However, targeting luminal bile acids can lead to gastrointestinal side effects and may interfere with the absorption of other medications and nutrients.

Other names

Bile saltsSteroid acidsPrimary bile acidsSecondary bile acidsCholic acid derivatives

Bile acid sequestrants are large, positively charged polymers that bind to negatively charged bile acids in the intestinal lumen through ionic bonding, forming an insoluble complex that is excreted in the feces, thereby preventing reabsorption and interrupting the enterohepatic circulation.