Thinking only in terms of total cholesterol circulating through the bloodstream may be misleading. In other words, the higher the HDL, the lower the risk of heart disease. This occurs whenever the intake of monounsaturated or polyunsaturated fats is greater and when saturated fat intake is low. All fats by nature tend to increase cholesterol and thus HDL, except polyunsaturated hydrogenated oils contained in some vegetable margarine. A good supply of monounsaturated and polyunsaturated fats appears to be crucial for a correct diet.
Vegetable oils supply important tocopherol for the diet.
The union between a diet rich in monounsaturated fats and discrete amounts of vitamin E may protect against arteriosclerosis. Although several studies of the past suggested that the substitution of saturated fats in the diet with polyunsaturated fats could prevent vascular disease, no study had evaluated the effect of a Mediterranean diet on the incidence of heart disease. It took the French Lyon Diet Heart Study to compare the cardiovascular effects of two different diets in subjects who had had a myocardial infarction. The following six dietary guidelines were given to the experimental group. This was a cultural aspect difficult to overcome.