bilesalt

Bile salts are conjugated bile acids that function as detergents to emulsify fats and facilitate lipid digestion. They are produced in the liver from cholesterol and secreted into bile. In humans, primary bile acids include cholic acid and chenodeoxycholic acid; these acids are typically conjugated with glycine or taurine to form bile salts such as glycocholate, taurocholate, glycochenodeoxycholate, and taurochenodeoxycholate.

After a meal, bile is released into the small intestine. Bile salts emulsify lipids, increasing the surface area available for pancreatic lipase and forming micelles that transport fatty acids and fat-soluble vitamins to enterocytes. Most bile salts are reabsorbed in the terminal ileum and returned to the liver via the portal circulation in a process known as enterohepatic circulation.

In the gut, microbial metabolism can deconjugate and modify bile acids, producing secondary bile acids such as deoxycholic acid and lithocholic acid. Ursodeoxycholic acid is another bile acid, more hydrophilic than many others, and is used therapeutically to dissolve certain cholesterol gallstones and to treat some cholestatic liver diseases.

Clinical relevance includes alterations in bile salt homeostasis during liver or biliary disease, which can lead to hepatocellular injury or malabsorption of fats. Bile salts are thus essential for efficient lipid digestion and for maintaining cholesterol and bile acid balance through hepatic synthesis, biliary secretion, and enterohepatic circulation.