[Nutrition and coronary heart disease: how important is diet?].

Three saturated fatty acids (C 12:0, C 14:0, C 16:0) raise LDL cholesterol but also HDL cholesterol levels. Replacement of these fatty acids by monounsaturated or omega-6 polyunsaturated fatty acids will lower LDL cholesterol as well as HDL cholesterol levels. Fat modified diets therefore may not improve the ratio of LDL to HDL cholesterol. Linoleic acid enhances sterol excretion but also increases cholesterol synthesis so that total body cholesterol is not diminished. Moreover various potentially adverse effects have been reported for n-6 polyunsaturated fatty acids. Recent cross-cultural ecologic studies as well as all major within-population cohort studies have not been able to find an association between cholesterol raising saturated fatty acids of animal fat and risk of Coronary Heart Disease (CDH). On the other hand several cohort and case control studies have shown an increase in CHD risk with increasing consumption of partly hydrogenated vegetable margarines. Meta-analyses of controlled intervention studies reveal that cholesterol lowering diets have failed to lower risk of CHD or total mortality. Yet controlled studies implementing a high level of antioxidants in the diet or increasing the n-3 unsaturated fatty acid content have been able to lower CHD and total mortality. It is time to discuss whether the concept of dietary intervention with the "classic" cholesterol lowering diet is still justified.