Influence of genetic polymorphisms on responsiveness to dietary fat and cholesterol.

Genes influence quantitative variations in plasma lipoprotein concentrations. For example, intake of dietary saturated fat and cholesterol raises the average serum cholesterol concentration, leading to a higher risk of coronary artery disease in populations. However, not all individuals within the population are susceptible: genetic factors appear to render individuals either "dietary responsive" or "dietary nonresponsive." In this review, we focus on current knowledge about the influence of genetic polymorphisms in certain genes on the lipoprotein response to dietary fat and cholesterol. Our preliminary studies in the Dietary Intervention Study in Children suggest a significant dose-response relation between the decrease in LDL cholesterol from baseline to 36 mo of follow-up in both the intervention group (who consumed a low-fat, low-cholesterol diet) and the usual care group (who consumed a regular diet) and the presence of the APOA1*A allele at the M1 site and the + site at the M2 site of the gene encoding apolipoprotein (apo) A-I. The DNA polymorphisms on the genes encoding apo A-IV, apo B, apo C-III, apo E, lipoprotein lipase, cholesteryl ester transfer protein, lecithin:cholesterol acyltransferase (phosphatidylcholine-sterol O:-acyltransferase), and LDL receptor were found by others to be associated with the plasma lipoprotein response to dietary intervention. Possible mechanisms involved in these effects are discussed and certain discrepancies in the literature about some genetic effects on responsiveness are analyzed. An improved understanding of the influence of specific genes on lipoprotein responsiveness to dietary fat and cholesterol may allow us to identify and counsel certain individuals to avoid high-fat diets so that they may reduce their risk of developing hyperlipidemia and coronary artery disease.