Dietary Lectin Lowers Serum Cholesterol and Raises Fecal Neutral Sterols in Cholesterol-Fed Rats

Abstract

This study examined the influence of a low level of dietary lectin (0.34%), at a dose that did not affect body weight or food intake, on the concentration of serum choles terol and fecal excretion of neutral sterols in rats fed a diet containing 0.50% cholesterol and 0.13% sodium cholate for 12 d. In experiment 1, rats fed a diet with 0.34% lectin, con canavalin A, had significantly lower concentrations of serum total cholesterol and hepatic cholesterol, a higher ratio of HDL-cholesterol to total cholesterol, enhanced excretion of fecal neutral sterols and reduced apparent cholesterol absorption or digestibility as com pared with rats fed a diet without lectin. Fecal excretion of acidic sterols was unaffected by dietary lectin. In contrast, dietary 0.34% lectin had no significant effect on concentrations of serum total protein or glucose. In experiment 2, we examined whether the cholesterol lowering activity of the lectin was responsibility for its carbohydrate-binding activity. The effect of dietary lectin on concentrations of serum and hepatic cholesterol and excretion of fecal neutral sterols was prevented by simultaneous administration of methyl-a-D-man nopyranoside with specific affinity for the carbohydrate-binding sites of the lectin. These results suggest that dietary lectins might reduce concentrations of serum and hepatic cho lesterol by a mechanism involving higher excretion of neutral sterols and that these alter ations might be associated with the carbohydrate-binding activity of lectin.