Dietary quercetin supplementation does not increase maximal oxygen uptake and physical work capacity

Abstract

Aim: Th e purpose of our study was to use a time-series design to investigate the eff ect of dietary quercetin supplementation on peak oxygen uptake (VO2peak) and physical work capacity. Methods and organization of the study: Nine recreationally-active men and women completed a treadmill-running graded exercise test (GXT) weekly (excepting wk 8) for 14 weeks. During the fi rst 3 and last 3 weeks, no quercetin supplementation was administered. During weeks 4-11, subjects ingested four soft Q-chews (Nutravail Technologies) per day containing quercetin (1 g/d), vitamin C, vitamin B3 and folic acid. A control group of 5 men were also tested during the fi rst and last week. Research results: VO2peak and test time remained stable throughout the 14 weeks at approximately 3.5±1.1 L/min and 6±1.6 min. Using a one-way repeated measures ANOVA, there was no signifi cant diff erence among means (P > 0.05) for either measure. Th ere was no trend for individual or mean values to increase above baseline during the treatment period. No changes occurred in the control group. Conclusions: We conclude that dietary quercetin supplementation with 1 g/d for 8 wk in non-endurance-trained men and women does not increase VO2peak or physical work capacity. Keywords: exercise, fl avonoids, muscle oxidative capacity, oxygen consumption