Abstract 4122: Quercetin Reduces Blood Pressure in Hypertensive Subjects
Epidemiological studies report that consumption of quercetin (Q), a flavonol found in fruits, vegetables and red wine, is inversely related to cardiovascular disease risk. We have shown that Q can reduce blood pressure in a hypertensive rodent model. However, the antihyperten-sive effect of quercetin has not been tested in humans. We hypothesized that a daily Q supplement can reduce blood pressure in hypertensive humans. Subjects (48±1 years old, BMI 29±1, systolic BP 138±2, diastolic BP 90±1 mmHg, n=26 men and n=21 women) completed a double-blind, placebo-controlled, crossover study that compared a 28d treatment of 365 mg Q/BID to placebo (P). There was a 2-week wash-in period in which subjects were instructed to discontinue existing supplement use prior to study enrollment, and a 2-week washout phase between Q and P treatments. During clinic visits at day 0 and day 28 of P and Q treatments blood pressure (BP), a fasting venous draw, and urine were collected. BP was measured using an Omron Analyzer in resting, seated patients. BP was recorded as the average of 3 measurements taken every 3 minutes. If there was more than <10% variation between BP readings, additional measurements were taken. There was no change in macronutrient or micronutrient intakes between Q and P as determined by 3-day diet records. Fasted plasma total cholesterol, HDL, LDL, triglycerides, and glucose levels were similar after Q and P. Plasma indices of oxidative stress as measured by Ferric Reducing Antioxidant Potential and Plasma Antioxidant Reserve were similar after Q and P, and there was no change in urinary isoprostane concentration. The cardiovascular effects of Q are summarized below. We report for the first time that supplemental quercetin can reduce BP and Rate Pressure Product in hypertensive humans. However, the mechanism does not appear to be related to an antioxidant effect, as has been previously reported in studies using animal models of hypertension.