The effect of weight reduction on biliary lipid metabolism in patients with hyperlipoproteinemia type IV.

Nine slightly obese patients with hyperlipoproteinemia type IV were studied, before and after a mean weight reduction of about 15 kg, with respect to bile acid kinetics, cholesterol balance and biliary lipid composition. The bile acid pool size was not consistently changed. The synthesis of cholic acid and chenodeoxycholic acid was decreased by about 65% and 50%, respectively. The net steroid balance, calculated as bile acid synthesis plus fecal excretion of neutral steroids minus dietary cholesterol intake, was reduced by about 50%. In all but one of the patients bile was supersaturated with cholesterol but weight reduction was not associated with any change in cholesterol saturation. The results indicate that hyperlipoproteinemia type IV may be associated with some metabolic defects which are not corrected for by weight reduction.