First Name:
Amanda
Last Name:
Martin
Major Department:
Exercise Science
Thesis Director:
David Nieman
Date of Thesis:
May 2009
Introduction: Endothelial dysfunction can often be a result of reduced nitric oxide bioavailability and is one factor that aids in the progression of many major diseases. Quercetin research has produced evidence to suggest that oral supplementation could improve nitric oxide levels via several different mechanisms. Increased nitric oxide concentrations might therefore result in improved endothelial function.
Purpose: The purpose of the following study was to examine the effects of quercetin supplementation on endothelial function in subjects at risk for heart disease.
Methods: Eighty-nine subjects, between the ages of 30 and 70, were recruited from the Quercetin, Upper Respiratory Tract Infection, Inflammation, Mental Vigilance, Blood Lipids, and Pharmacokinetics: A Community Clinical Trial in which the subjects were undergoing daily oral supplementation of either: placebo, quercetin-500 mg, and quercetin-1000 mg. Each subject participated in a fifteen minute endothelial function test by means of the EndoPAT 2000. The reactive hyperemic index (RHI), which correlates with endothelial function, was determined by comparing peripheral blood flow before and after an anoxic phase.
Results: There were no significant results between RHI and treatment group when the subject population was evaluated as a whole. The treatment groups were then divided by age into two subsets: <48 and ≥48. Both quercetin treatments increased RHI values compared to placebo (Q-500: 25%, Q-1000: 15%). The quercetin-500 mg/day treatment in the <48 subset produced a significant difference compared to the placebo (p-value = 0.018).
Conclusion: Quercetin supplementation of 500 mg per day seems to have a positive effect on endothelial function in adults under the age of 48.