Independent effects of dietary saturated fat and cholesterol on plasma lipids, lipoproteins, and apolipoprotein E

Nine normolipidemic males (1 8-37 years) were fed formula diets containing (as % of calories) egg white protein (1 5%), glucose polymer:sucrose, 3: 1 (54%), and fats (3 1 %) as one of the following: corn oil (corn), corn oil plus 1 gram/ day cholesterol (corn+), coconut oil (coco), coconut oil plus 1 gram/day cholesterol (coco+). Two dietary periods of 18 days each were separated by 1 month during which plasma lipid levels returned to prestudy values. A given dietary period consisted of 9 days of either corn or coco feeding allowed by 9 days of corn+ or coco+, respectively. Fasting plasma samples were taken the last 3 days of each 9-day interval. Lipids were determined by standard procedures and the apoE levels in lipoprotein fractions isolated by discontinuous density gra- dient ultracentrifugation were determined by radioimmu- noassay. The biochemical variables measured were: total plasma, VLDL, IDL + LDL, and HDL, cholesterol, triglyc- eride, and apoE levels, as well as the apoE of plasma d > 1.17 g/ml. The effects of apoE phenotype, the type of dietary oil (corn versus coco), the presence or absence of dietary choles- terol, and the day of sampling within triplicates on the above variables were assessed statistical1y.l The type of oil had the only significant effect on any variable. At P < 0.01, the coconut oil diets were associated with significant elevations (as com- pared to corn oil) of the following nine variables: total, VLDL, IDL + LDL, and HDL cholesterol; total, VLDL, and IDL + LDL apoE; total and VLDL triglycerides.-Fisher, E. A., C. B. Blum, V. I. Zannis, and J. L. Breslow. Independent effects of dietary saturated fat and cholesterol on plasma lipids, lipoproteins, and apolipoprotein E. J. Lipid Res. 1983. 24: 1039-1 048.