Serum Lipid and Blood Pressure Responses to Quercetin Vary in Overweight Patients by Apolipoprotein E Genotype

Our objective was to examine the effect of a quercetin supplementation on blood pressure, lipid metabolism, markers of oxidative stress, inflammation, and body composition in an at-risk population of 93 overweight-obese volunteers aged 25-65 y with metabolic syndrome traits in relation to apolipoprotein (apo) E genotype. Participants were randomized to receive 150 mg/d quercetin in a double-blinded, placebo-controlled, crossover trial with 6-wk treatment periods separated by a 5-wk washout period. Retrospectively, 5 apoE genotype variants were found (epsilon 2/epsilon 3, n = 3; epsilon 3/epsilon 3, n = 60; epsilon 3/epsilon 4, n = 23; epsilon 2/epsilon 4 n = 4; and epsilon 4/epsilon 4, n = 3). Participants were classified into the following 3 apoE phenotypes: apoE2 In = 3), apoE3 In = 60), and apoE4 (n = 26). Data were analyzed for apoE3 and apoE4 subgroups. Quercetin decreased systolic blood pressure by 3.4 mm Hg (P < 0.01) in the apoE3 group, whereas no significant effect was observed in the apoE4 group. Quercetin decreased serum HDL cholesterol (P < 0.01) and apoA1 (P < 0.01) and increased the LDL:HDL cholesterol ratio (P < 0.05) in the apoE4 subgroup, whereas the apoE3 subgroup had no significant changes in these variables. Quercetin significantly decreased plasma oxidized LDL and tumor necrosis factor-alpha in the apoE3 and apoE4 groups, whereas no significant inter-group differences were found. Serum C-reactive protein and nutritional status (body weight, waist circumference, fat mass, fat-free mass) were unaffected compared with placebo. In conclusion, quercetin exhibited blood pressure-lowering effects in overweight-obese carriers of the apo epsilon 3/epsilon 3 genotype but not in carriers of the epsilon 4 allele. Furthermore, quercetin supplementation resulted in a reduction in HDL cholesterol and apoA1 in apo epsilon 4 carriers. J. Nutr. 140: 278-284, 2010.