BackgroundThe apolipoprotein E polymorphism may influence the absorption of cholesterol from the intestine and thus the response of serum cholesterol to diet. We decided to use plant sterols to investigate this and studied whether the cholesterol-lowering effect of plant sterols differed between subjects with different apolipoprotein E genotyes. DesignThirty-one healthy subjects with the E3/4 or E4/4 genotype and 57 with the E3/3 genotype were fed sterol-enriched margarine or control margarine for 3 weeks each in a blind randomised cross-over design. The sterol margarine provided 3?2 g of plant sterols daily, was low-fat, and had the same fatty acid composition as the control margarine. Subjects used the margarines as part of their usual diet, which was fairly low in cholesterol (mean, 175 mg per day). The mean (± standard deviation) age of the subjects was 25 (± 11) years. ResultsThe apolipoprotein E polymorphism did not significantly affect the responses of total and LDL cholesterol. The decrease in total cholesterol was 0?36 mmol L1 (7?4€in the E3/3 subjects and 0?31 mmol L1 (5?7€in the 4 subjects (P = 0?50) and that in LDL cholesterol was 0?34 mmol L1 (12?2€in the E3/3 subjects and 0?32 mmol L1 (9?8€in the 4 subjects (P = 0?68). ConclusionThe serum cholesterol response to plant sterols is not affected by the apolipoprotein E polymorphism in healthy subjects who consume a low-cholesterol diet.