Effect of β-sitosterol alone or in combination with chenic acid on cholesterol saturation of bile and cholesterol absorption in gallstone patients

Abstract

Studies aimed at testing whether β-sitosterol, a plant sterol known to block cholesterol absorption, would induce bile cholesterol desaturation or enhance the desaturating effect of chenic acid were carried out in 7 gallstone patients. Cholesterol absorption was also measured. β-Sitosterol (250 mg/ kg-day) or chenic acid (10 mg/kg-day) was fed alone or in combination for 6-wk randomized periods. At the end of each period, fasting-state duodenal bile was obtained for lipid analysis and biliary bile acid composition; cholesterol absorption was measured by an isotope ratio technique. β-Sitosterol caused no significant bile desaturation, despite its markedly decreasing cholesterol absorption. Chenic acid lowered bile saturation, but bile remained supersaturated at this low dosage; addition of β-sitosterol induced no additional desaturation. Cholesterol absorption, averaging 48%, remained unchanged (43%) during chenic administration. The results suggest that β-sitosterol has little influence on bile saturation and therefore is of little therapeutic value for the treatment of cholesterol gallstones, either alone or in combination with chenic. The results also indicate that the desaturating effect of chenic, at least at this dosage, is not mediated by changes in cholesterol absorption, and they confirm previous studies showing no association between changes in bile cholesterol and serum cholesterol levels. The results also imply that variations in the amount of dietary cholesterol are unlikely to be an important determinant of bile saturation in gallstone patients.