The effects of quercetin supplementation on cognitive functioning in a community sample: a randomized, placebo-controlled trial.

ABSTRACT

BACKGROUND: The purpose of the present study was to examine the effects of quercetin supplementation on neurocognitive functioning. METHODS: A large community sample (n = 941) completed a 12-week supplementation protocol, and participants were randomly assigned to receive 500 mg/day or 1000 mg/day quercetin, or placebo. RESULTS: Results failed to indicate significant effects of quercetin on memory, psychomotor speed, reaction time, attention, or cognitive flexibility, despite large increases in plasma quercetin levels among the quercetin treatment groups. DISCUSSION: Consistent with recent research, this study raises concerns regarding the generalizability of positive findings of in vitro and animal quercetin research, and provides evidence that quercetin may not have an ergogenic effect on neurocognitive functioning in humans.