Hypocholesterolaemic effect of animal and plant fats in rats

Abstract

Triglvcerides, containing approximately the same amounts of essential fatty acids (EFA) but differing in the positions of esterified EFA, were preparedfrom soy bean oil and lard, and were administered to male rats. After 6 weeks of feeding, weanling rats on either 1 or 5% (w/w) of lard fat had a higher plasma cholesterol level than animals on the corresponding levels of fat from soy bean oil. Similar results were obtained when cholesterol (1%) and cholic acid (0.25%) were included together in the diets. The plasma cholesterol level in rats fed 5% fat of soya source was lower than that in EFA deficiency. Hepatic cholesterol was strikingly elevated after the rats had been fed lard fat and cholesterol plus cholic acid compared with fat from soy bean oil and cholesterol plus cholic acid. When these fats were fed at the 10% level to mature rats for 2 weeks, the plasma cholesterol level in animals fed lard fat with cholesterol plus cholic acid was slightly higher than that in rats given the vegetable fat. The results suggest that differences in the positional distribution of EFA in the glyceride molecule may be responsible for the different concentrations of cholesterol induced by the two fats tested. Thus, EFA at the 1 and 3 positions in triglycerides may have less hypocholesterolaemic action than EFA at the 2 position.