Role of dietary saturated fatty acids on lowering the incidence of heart lesions in male rats.

Male weanling rats were fed soybean or low erucic acid rapeseed oils alone or in combination with cocoa butter (a source high in saturates) or triolein for 16 weeks. All diets contained 20% by weight of the test oils. The apparent digestibility of all diets and test oils increased with the age of the rat. The apparent digestibility of saturated fatty acids was lower in rats fed the diets containing cocoa butter. The relative organ weights, however, were not affected by diet, but growth was improved by supplementing the vegetable oils with cocoa butter. This growth difference was significant for the addition of cocoa butter to low erucic acid rapeseed oil. After 16 weeks all groups of rats developed myocardial necrosis. A dramatic lowering of myocardial lesion incidence was observed in rats fed diets enriched with saturated fatty acids. The results of the present experiment suggest that enriching a vegetable oil with saturated fatty acids affects both nutritional and cardiopathological properties of the oil.