The investigators suggested that slow intestinal transit could enhance the formation and absorption of deoxycholate from the colon. Deoxycholate, a secondary bile salt, promotes the hepatic secretion of cholesterol and favors the nucleation of cholesterol crystals. Subjects with slow intestinal transit have been shown to have high biliary deoxycholate concentrations. When constipated subjects were given effective doses of laxatives, bile deoxycholate and cholesterol concentrations decreased. Comparative studies have shown that women have slower intestinal transit and more constipation than men, and this may explain why they have a higher incidence of gallstones.
Dietary fiber is known to decrease intestinal transit time.