Towards an improved lipid-lowering diet: additive effects of changes in nutrient intake.

To identify diets that are more effective than existing ones in reducing lipoprotein-mediated risk of atherosclerotic heart disease, the serum lipids and lipoprotein response to three modified diets was studied in twelve normal men living in an institution. The "Western" reference diet (40% energy from fat, P/S ratio 0.27) was compared in Latin square design with a fat-modified diet (diet B, 27% energy from fat, P/S 1.0, reduced cholesterol content); with a fat-modified diet supplemented with fruit, vegetable, and cereal fibre (diet C); and with a diet providing 40% energy from fat, having P/S ratio 1.0 and supplemented by fibre (diet D). The effects of fat modification and fibre-supplementation (diets C and D) were strongly additive-a fall serum cholesterol by 24-29%, in low-density-lipoprotein (LDL) cholesterol by 31-34%, and in serum triglyceride by 21-26%; and the reduction, by diet C, of the ratio of serum cholesterol to high-density-lipoprotein (HDL)-cholesterol by 21%, and that of LDL-cholesterol to HDL2-cholesterol by 26%. The additive effects of multiple changes in nutrient intake, each moderate in extent, permits the design of diets which are remarkably effective in reducing serum-cholesterol level.