Dietary fat and cholesterol effects on plasma low density lipoproteins in pedigreed baboons

To determine dietary and genetic effects on LDL phenotypes, such as LDL-C and apoB concentrations, particle diameters and LDL-C size distribution, 150 pedigreed baboons, members of 19 sire groups, were fed a sequence of three diets differing in fat and cholesterol levels. LDL-C was measured by the use of heparin-Mn²⁺, apoB by competitive immunoassay, and LDL particle diameters were characterized by nondenaturing gradient gel electrophoresis and densitometry. Elevating dietary fat from 10% to 40% of calories, resulted in modest, but significant, increases of all LDL phenotype measures; whereas, elevating the level of cholesterol in the high fat diet resulted in relatively larger increases. There were significant sire effects and sire x diet interactions for the LDL measures. The results of the present study indicate genes affect the expression of LDL phenotypes on each of the three diets, as well as the patterns of response to dietary changes.