Orlistat reduces gallbladder emptying by inhibition of CCK release in response to a test meal.
Level 2 - randomized trial
Randomized controlled trial in healthy humans
PubMed 17175037 · doi:10.1016/j.regpep.2006.11.016
What was done
Twenty-two healthy volunteers consumed a high-fat test meal (200 ml dairy cream and chocolate powder; 552 kcal, 56.0 g fat) with and without 120 mg oral orlistat. Gallbladder volume was measured using ultrasound at baseline and 5, 10, 20, 30, and 40 minutes after meal ingestion. Venous blood samples were collected concurrently to measure bioactive CCK levels via a rat pancreatic acini cell bioassay.
What was found
Orlistat significantly reduced postprandial gallbladder emptying: gallbladder contraction was 78.5% in the control condition versus 45.7% with orlistat (p < 0.01), with maximal emptying delayed by up to 10 minutes. Peak bioactive CCK levels were reduced by 47% (7.8 pmol/l without orlistat vs. 4.1 pmol/l with orlistat), and maximal CCK secretion was also delayed by up to 10 minutes.
Why it matters
By blocking intestinal fat digestion, orlistat blunts lipid-triggered CCK release and impairs gallbladder contraction. This mechanism suggests that long-term orlistat use could promote biliary stasis, potentially increasing the risk of gallstone formation during obesity management.
Limits
The trial included a small sample size (n = 22) of healthy volunteers rather than the target clinical population of individuals with obesity. It only evaluated an acute response to a single high-fat meal over 40 minutes and did not assess clinical biliary endpoints or long-term gallstone risk.
Cited by
- supports Ingesting dietary fat triggers the contraction of the gallbladder to expel bile.