| Two biological models were examined for possible effects of trans-unsaturated fatty acids. In Experiment I weanling swine were fed for six months high fat diets containing as fat source, a high oleic acid safflower oil, lard, or a partially hydrogenated soybean oil blended with soybean oil. The extent of atherosclerosis in left coronary arteries and the ability of vascular components to synthesize eicosanoids important for blood clotting were determined. There was no significant difference (p > 0.05) in the extent of atherosclerosis or the synthesis of thromboxane A. Significant effects were observed on serum cholesterol, which was elevated in the lard fed group, serum triacylglycerol, which was highest in the safflower oil group, and prostacyclin synthesis, which was depressed in both the lard and hydrogenated soybean oil diets compared to the safflower oil diet. No unique effect on the development of heart disease appears to be attributable to hydrogenated fats. The hydrogenated fat was similar to lard in decreasing prostacyclin synthesis, suggesting that the saturation of dietary fatty acids may be a contributory factor in the development of heart disease, through its effect on thrombotic processes. In Experiment II weanling rats were fed semi-purified diets containing 15% by weight of either corn oil, a high oleic acid safflower oil, lard or hydrogenated soybean oil. Significant changes in the fatty acid composition of heart mitochondrial preparations were induced by these dietary fats. Despite these changes in membrane composition, no effects on the respiratory properties of the mitochondria were observed. These results suggest that mitochondrial membranes adapt to changes in dietary fatty acids in a way which prevents changes in their functional properties. |
