Expansion
Bile salts are reabsorbed in the terminal ileum and returned to the liver by the portal vein
Expansion
- Bile salts are secreted by the liver into the biliary tree
- Stored and concentrated in the gallbladder
- Released into the duodenum to emulsify fat
- Reabsorbed actively in the terminal ileum
- Returned to the liver in the portal vein and re-secreted
About 95 per cent are recovered, so a pool of only 3 to 4 g circulates 6 to 8 times a day and supports the secretion of 20 to 30 g of bile salts daily.
Interrupting the loop by terminal ileal resection or Crohn’s disease produces:
- Bile salt diarrhoea - unabsorbed salts irritate the colon; treated with a bile acid sequestrant
- Gallstones - a depleted bile salt pool leaves bile supersaturated with cholesterol
- Steatorrhoea and fat-soluble vitamin deficiency if depletion is severe
- Oxalate renal stones - unabsorbed fat binds calcium, leaving oxalate free to be absorbed