8th February 2024

Bile salts

Bile salts are constantly produced by the liver and are excreted by the large intestine. This consists of primary and secondary bile salts. Primary bile salts consist of cholic acid and chenodeoxycholic acid. They are synthesised from cholesterol by hepatocytes. Intestinal bacterial enzymes convert secondary bile salts from primary bile salts, consisting of deoxycholic acid and lithocholic acids.

Bile salts aim to solubilise dietary lipids by emulsifying fats into phospholipids and fatty acids. It also forms micelles to help solubilise cholesterol and fatty acids. This helps with the absorption of fatty acids, cholesterol and fat-soluble vitamins. 

CCK, gastrin and secretin stimulate the secretion of bile. CCK stimulates the contraction of the sphincter of Oddi, while gastrin and secretin stimulate the production of bile and HCO3-. Increased parasympathetic stimulation also increases the secretion of bile.