The effect of beta-sitosterol on the metabolism of cholesterol and lipids in rats on a diet containing coconut oil

1. Intraperitoneal injection of beta-sitosterol (5mg./rat/day for 25 days) into 1-year-old male Wistar rats fed on a low-fat diet supplemented with 10% of coconut oil resulted in a lowering of cholesterol and lipid concentrations in the tissues. 2. beta-Sitosterol increased the rate of biosynthesis of cholesterol and lipids in the tissues, but to an even greater extent enhanced their oxidative degradation. 3. The present results are similar to those previously obtained on a low-fat diet, indicating that the presence of fat had no marked effect on the action of beta-sitosterol.

Effects of cholesterol and ß-sitosterol in the gerbil

The effect of increasing levels (0–1.0%) of dietary cholesterol has been studied in the Mongolian gerbil. A consistent and proportional elevation of serum cholesterol was observed after one week of cholesterol administration. In addition, the simultaneous administration of ß-sitosterol prevented this hypercholesteremia.

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.