Bile acids and dietary lipids

Bile acids and dietary lipids in the intestinal lumen represent a complex physiological environment and a set of substrates rather than a single molecular target. Bile acids are amphipathic steroid molecules synthesized from cholesterol in the liver and stored in the gallbladder; upon meal ingestion, they are secreted into the duodenum to emulsify dietary lipids, facilitating their breakdown by lipases and subsequent absorption (StatPearls, 2023). In a pharmacological context, bile acids themselves serve as the target for bile acid sequestrants, such as cholestyramine and colesevelam, which bind to these acids in the lumen to form insoluble complexes that are excreted in the feces (PubChem, 2024). This process interrupts the enterohepatic circulation, forcing the liver to upregulate LDL receptor expression to convert more systemic cholesterol into bile acids, thereby lowering plasma LDL-C levels (LiverTox, 2020). Dietary lipids are also indirectly targeted by drugs like orlistat, which inhibits the gastric and pancreatic lipases required for lipid hydrolysis, leading to decreased fat absorption and increased fecal fat excretion (PubMed, 2021). Therapeutic manipulation of these luminal components is primarily used to treat hyperlipidemia, obesity, and bile acid-induced diarrhea, though it can lead to side effects such as malabsorption of fat-soluble vitamins and gastrointestinal discomfort (Mayo Clinic, 2023).

Other names

Bile saltsIntestinal lipidsLuminal bile acidsDietary fatsBiliary acids

Bile acid sequestration and inhibition of dietary lipid hydrolysis