Response of serum lipids and lipoproteins o man to beta-sitosterol and safflower oil; a longterm study.

Previous studies in man have indicated that administration of either plant sterols or unsaturated dietary fats causes decreases in certain serum lipids. This report presents the results of a long-term 7-phase study of the comparative effects of the single and combined administration of plant sterols (p-sitosterol) and a highly unsaturated vegetable oil (safflower oil) in 15 ambulatory subjects. The serum lipid changes observed indicate that both agents act on the same low-density lipoprotein fraction, that the changes produced by /-sitosterol and by safflower oil are similar in magnitude, but that the combination has a .55 per cent greater effect than either agent alone, that the mechanisms of action of these 2 agents probably differ, and that the action of the safflower oil is probably not due to the amount of sitosterol it contains.