Regression Studies with Safflower Oil and Sitosterol in Rabbit Atherosclerosis

Hypercholesteremia with atherosclerosis was induced in male rabbits by feeding hydrogenated coconut oil as the only lipid in a purified diet. Replacing the hydrogenated coconut oil by safflower oil produccd a profound fall in plasma cholesterol in rabbits. Supplementing the safflower oil with βsitosterol at 3 per cent of the oil weight caused an even greater decrease in plasma cholesterol. Although in both cases the further development of aortic atheroma was arrested, there was no detectable regression of existing lesions, over 24 weeks. Hydrogenated coconut oil feeding produced high plasma and liver cholesterol levels in rabbits. When small amounts of safflower oil were fed in addition to the hydrogenated coconut oil, the elevation of plasma or liver cholesterol was much less.