The use of diet to lower plasma cholesterol levels

The basic principle of a lipid lowering diet is restriction of saturated fat intake. This can be achieved by reducing the consumption of dairy products and fats of animal origin. To keep energy intake constant (in normal weight individuals) complex carbohydrate or unsaturated fat is substituted for saturated fat. Diets with various proportions of complex carbohydrate, monounsaturated fatty acids, and polyunsaturated fatty acids have been proposed. In theory, the latter should be the best substitute for saturated fatty acids in a lipid lowering diet. Polyunsaturated fat has cholesterol lowering activity that is additive to the effect obtained by reducing the amount of dietary saturated fat. In practice, either polyunsaturated fatty acids or monounsaturated fatty acids or complex carbohydrate exert very similar effects on plasma cholesterol levels when substituted for saturated fatty acids in a lipid lowering diet. Their effects on plasma triglyceride are, however, dissimilar. Increased consumption of polyunsaturated fat leads to pronounced reduction in plasma triglyceride concentrations. Conversely, a high carbohydrate diet has a hypertriglyceridemic effect that is more pronounced in individuals with diabetes or preexisting hypertriglyceridemia. Dietary cholesterol should also be reduced in order to lower plasma cholesterol levels. However, the hypocholesterolemic effect of this measure has a large interindividual variation which is further influenced by the fat composition of the diet. Dietary fibre has received attention in more recent years for its ability to reduce plasma cholesterol levels. Fibre rich foods are not equally effective in this respect, the most active being legumes, fruit and vegetables. When high carbohydrate-high fibre diets are consumed, the hypertriglyceridaemic effect of carbohydrate is counteracted by dietary fibre.(ABSTRACT TRUNCATED AT 250 WORDS)