Cholesterol absorption and sterol balance in normal subjects receiving dietary fiber or ursodeoxycholic acid.

Twelve normal subjects were placed on a constant diet and evaluated during three treatment periods, each lasting four weeks. Patients received regular diet alone during period A, regular diet plus 60 g/day wheat bran during period B, and regular diet plus 15 mg/kg/day ursodeoxycholic acid during period C. Cholesterol absorption, plasma lipid concentration, daily fecal excretion of neutral and acidic sterols, and sterol balance were determined following each treatment. No changes in serum lipid levels are observed in the three study periods. Bran administration increases fecal neutral sterol excretion and decreases cholesterol absorption (from 50.1 to 42.0%) with respect to period C. Ursodeoxycholic acid administration has no effect on fecal neutral sterol excretion, whereas bile acid excretion is markedly increased. Sterol balance (evaluated as neutral and acidic fecal sterols excreted per day minus dietary cholesterol plus ursodeoxycholic acid given per day) is lower during ursodeoxycholic acid feeding (360 +/- 145 mg/day) than during bran feeding (593 +/- 174 mg/day). In conclusion, ursodeoxycholic acid decreases sterol balance values; bran-rich diet increases sterol balance and reduces cholesterol absorption.