The results of this research are consistent with a growing body of literature raising concerns about the generalizability of findings from in vitro and animal quercetin research to human populations. For example, animal research has suggested that quercetin supplementation may have an ergogenic effect, with results indicating that mice who received 1 week of quercetin demonstrated significant increases in muscle oxidative capacity and endurance [Davis et al. 2009]. Inhibitors,research,lifescience,medical However, research on the potential ergogenic effect of quercetin in human participants has generated largely inconsistent findings. Although some research has suggested that quercetin

ingestion may be associated with small improvements in physical performance (e.g.

Inhibitors,research,lifescience,medical 3%) among trained males [Nieman et al. 2010], other studies have failed to find any evidence of quercetin-induced performance ref 1 enhancement among human samples [e.g. Cheuvront et al. 2009; Cureton et al. 2009; Nieman et al. 2007]. Similarly, recent research failed to detect immediate effects of Inhibitors,research,lifescience,medical 2000 mg of quercetin on vigilance among human samples. The results of the present study, though novel in that they pertain to the cognitive effects of long-term quercetin supplementation, are consistent with the null ergogenic findings of several prior quercetin trials, and suggest that quercetin may not be associated with enhanced cognitive or physical functioning. Thus, research to date appears to suggest that, at best, quercetin’s ergogenic effects are far below that reported in mice. Inhibitors,research,lifescience,medical Additional research is needed to determine which, if any, physiological, cognitive, and psychological benefits of quercetin noted in animal and in vitro research extend to humans. This research has many strengths Inhibitors,research,lifescience,medical that enhance confidence in the results obtained, including the use of a large community sample of adults ranging in age from 18 to 85 years, a placebo-controlled double-blind methodology,

a full 12 weeks of supplementation, blood monitoring of quercetin levels Cilengitide at baseline and post treatment, and multiple assessments of a variety of cognitive functions. However, several limitations are worth noting as well. For example, although the cognitive tests participants completed were objective, STI 571 standardized tests based on popular, well validated measures of neuropsychological functioning, several of the subtests on the CNS Vital Signs battery are relatively brief and may not be sensitive enough to detect very subtle changes in neuropsychological functioning. Future research may wish to include lengthier, more in-depth assessments of cognitive domains thought to be affected by quercetin. In addition, practice effects are a well documented concern with the repeated administration of many cognitive tests [e.g. Dikmen et al. 2000].