Effect of quercetin supplementation on blood pressure in patients with a history of ischemic stroke

Cerebrovascular disease including ischemic and hemorrhagic stroke is one of the most prevalent and destructive disease. Accompanying Hypertension with cardiovascular disease will increase the risk of coronary heart disease and stroke. A Few studies examined the effects of quercetin supplementation showing its protective effect on endothelial function. Animal studies have shown that quercetin supplementation increases nitric oxide bioavailability and therefore helping the blood vessels to dilate. Quercetin supplementation has favorable effects in patients with stroke. Our objective was to examine the effect of quercetin supplementation on blood pressure in patients with a history of ischemic stroke. Seventy-two patients aged 50-75 years with a history of ischemic stroke including men and women with 25 < BMI < 35 kg/m² have been selected. Subjects were randomized into quercetin supplementation and placebo group. These patients received 1000 mg quercetin/d or placebo for 8 weeks. Weight, height and systolic and diastolic blood pressure were measured before and after the intervention. Also the daily intakes of food were evaluated by 24-hour questionnaire. Significant changes of systolic (13.7±2.33 mmHg vs 12.88±1.89 mmHg, p=0.04) and diastolic blood pressure (8.66±1.45 mmHg vs 8.26±0.98 mmHg, p=0.02) were observed by taking quercetin. There were no significant changes in weight and the daily intakes of energy and macronutrients between 2 groups and dietary intake of quercetin was not different after intervention. According to the results, quercetin supplementation might improve endothelial function by lowering blood pressure in patients with a history of ischemic stroke.