Effect of type of dietary fat, cholesterol and chenodeoxycholic acid on gallstone formation, bile acid kinetics and plasma lipids in squirrel monkeys.

To explore the effect of type of dietary fat, cholesterol and chenodeoxycholic acid on gallstone formation, bile formation, bile composition, bile acid kinetics and plasma lipids in squirrel monkeys, 39 monkeys were studied using seven different diets. Safflower oil, a highly unsaturated fat, added to a diet with cholesterol resulted in at least as high an incidence of cholesterol gallstones as butter added to the same diet. On the other hand, diets with high levels of saturated or unsaturated fat without cholesterol did not result in gallstone formation. Dietary chenodeoxycholic acid (0.1%) did not reduce the incidence of cholesterol gallstones, although the proportion of bile acids as chenodeoxycholic acid increased. Gallbladder biles from monkeys fed semipurified diets with cholesterol had a significantly higher lithogenic index than the comparable groups without cholesterol. Pool sizes of bile acids in all semipurified diet groups were reduced and the lithogenic indices were increased compared with the group fed a commercial feed. Dietary chenodeoxycholic acid caused a decrease in plasma cholesterol in butter groups and an increase in triglyceride concentrations in safflower groups. Diet infuences bile composition and bile acid kinetics, as well as the incidence of gallstones, in squirrel monkeys.