Protective effect of plant sterols against chemically induced colon tumors in rats.

Diets rich in vegetables are associated with a low incidence of colon cancer. Since plant sterols are plentiful in vegetarian diets, we studied the effect of beta-sitosterol on colon tumor formation in rats treated with the carcinogen N-methyl-N-nitrosourea. We demonstrated that beta-sitosterol nullified in part the effect of this direct-acting carcinogen on the colon. We suggest that plant sterols may have a protective dietary action action to retard colon tumor formation. The beneficial effects of vegetarian diets may be enhanced because of the presence of these compounds.