SUPPLEMENTATION WITH QUERCETIN MARKEDLY INCREASES PLASMA QUERCETIN CONCENTRATION WITHOUT EFFECT ON SELECTED RISK-FACTORS FOR HEART-DISEASE IN HEALTHY-SUBJECTS

The purpose of this double-blind study was to investigate the influenc e of adding a quercetin-containing supplement to the diet on plasma qu ercetin status, serum/platelet fatty acid levels and risk factors for heart disease. Healthy men and women with cholesterol levels of 4.0-7. 2 mmol/L, consumed four capsules daily of either a quercetin-containin g supplement (1.0 g quercetin/d) or rice flour placebo for 28 d. Querc etin intakes were similar to 50-fold greater than the dietary intakes associated with lower coronary heart disease mortality on the basis of epidemiologic studies. Subjects consuming quercetin-containing capsul es had plasma quercetin concentrations similar to 23-fold higher than those of subjects consuming the control capsules. Quercetin supplement ation did not modify serum total, LDL or HDL cholesterol or triglyceri de levels. There were also no alterations of other cardiovascular dise ase or thrombogenic risk factors, including platelet aggregation, plat elet thromboxane B-2 production, blood pressure or resting heart rate. Furthermore, there was no effect on the levels of (n-6) or (n-3) poly unsaturated fatty acids in serum or platelet phospholipids. In conclus ion, supplementation with quercetin-containing capsules markedly enhan ced the plasma quercetin concentration but had no effect on other card iovascular or thrombogenic risk factors.