APOLIPOPROTEIN-E POLYMORPHISM AND DIETARY PLASMA-CHOLESTEROL RESPONSE

All studies have demonstrated a strong association between plasma chol esterol and apoE phenotypes in the following order: E(4)/E(4) > E(4)/E (3) > E(3)/E(3) > E(3)/E(2). It has been thought possible that the apo E gene might be involved in the modulation of dietary plasma cholester ol responses, perhaps explaining-the differences in cholesterol concen trations. Some dietary intervention studies have suggested that apoE(4 ) individuals react to dietary change with exaggerated cholesterol res ponses. In one study, apoE(4)/E(4) individuals. responded by increased cholesterol reductions during low fat intake, and by increased choles terol elevations during switchback to high fat diet. Plausible mechani sms have been postulated which could explain such differences. However , other studies have reported no differences in plasma lipid responses among apoE phenotypes. The studies cannot be directly compared becaus e of different designs and study populations with differing apoE allel e frequencies. Thus the possible role of genetic variation in the apoE gene in the modulation of dietary plamsa lipid responses remains to b e confirmed in prospective dietary studies, involving diets both rich and poor in far and cholesterol.