Response of Serum Lipids and Lipoproteins

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.