Dietary interventions that lower lipoproteins containing apolipoprotein C-III are more effective in whites than in blacks: results of the OmniHeart trial.

Description

This study sough to compare the concentration of apolipoprotein (apo) CIII in VLDL and LDL between Blacks and Whites and to examine racial differences in the response of these lipoprotein risk factors to dietary intervention. The participants (89 Blacks and 73 Whites) were part of the Optimal Macronutrient Intake Trial to Prevent Heart Disease (OmniHeart) which is a randomized, 3-period feeding study to compare the effect of 3 healthy diets emphasizing either carbohydrate (CARB), unsaturated fats (UNSAT) or protein (PROT). They were ≥30 years of age with prehypertension or hypertension. At baseline, Blacks had a much lower concentration of atherogenic LDL lipoproteins containing apo CIII than Whites. The controlled study diets lowered plasma apo CIII and triglyceride concentrations compared to baseline concentrations in Whites, reducing racial differences. After the study diets, Blacks continued to have lower LDL with apo CIII even after adjustment for insulin sensitivity and obesity. The authors suggested that there must be inherent racial differences in the metabolism of apo CIII containing apo B lipoproteins to explain this more favourable lipoprotein profile in Blacks. In accordance, the ratio of molecules of apo E to apo B in LDL with and without apo CIII was higher in Blacks than in Whites which was associated with a higher clearance of atherogenic particles. These results suggest that dietary therapies to reduce apo CIII and triglycerides appear to be more effective in Whites than in Blacks.