These researchers later showed that dietary ingestion of Cardio Clear 7 Ingredients Review quercetin from onion soup also helped inhibit platelet aggregation. And in a study of 30 men who already had coronary heart disease, Greek cardiologists showed that a red grape polyphenol extract rich in quercetin caused an increase in flow-mediated dilation of major arteries, a potent indicator of improved endothelial health. The natural next step was to study quercetin supplements alone and their effect on blood pressure, a study undertaken at the University of Utah in 2007. They studied 19 patients with pre-hypertension and 22 with stage 1 (early) hypertension, supplementing them with placebo or 730 mg quercetin/day for 28 days.
There was no effect on the pre-hypertensive patients, but the hypertensive group enjoyed reductions in both systolic and diastolic blood pressure (average 7 mmHg and 5 mmHg reductions, respectively)meaningful changes that lower vascular disease risk. In 2008, a randomized, placebo-controlled crossover trial in 12 healthy men showed biochemical evidence of improved endothelial function (such as augmentation of nitric oxide status) with as little as 200 mg/day of quercetin. Together, these effects point to an important role for quercetin in protecting cardiovascular health.
Despite being the most common and best studied of the polyphenols, quercetin has been largely neglected in the public eye until recently, as new research has revealed its astonishing potential as a health-promoting, disease-preventing supplement. Quercetin's powerful antioxidant effects directly reduce tissue damage and have now been shown to prevent diseases such as cardiovascular disease. Health care practitioners recommend quercetin in doses ranging from 50 mg to 500 mg, one to three times daily. Quercetin, a ubiquitous polyphenol found especially in apples, onions, and red grapes has been ignored for years while other members of its class took the limelight. In just the past two years, however, a virtual explosion of information has emerged about this versatile molecule.