Does Quercetin Supplementation Promote Biological Changes and Performance in Athletes? A Systematic Review

Abstract

Background: Summarize the available evidence in the literature regarding the repercussions generated by quercetin supplementation in amateur and professional athletes. Methods: Searches were conducted in four databases, Cochrane Library (23 articles), PubMed/Medline (37 articles), Scopus (70 articles), and Excerpta Medica Database (EMBASE) (72 articles), which were subjected to eligibility criteria. Results: Out of 202 articles found, 95 duplicates were removed, and 107 articles were analyzed for the inclusion process. Then, 784 studies were excluded after title/abstract evaluation, resulting in 17 articles of which 13 were included in this systematic review. After quercetin supplementation, alterations in aspects related to the inflammatory response were observed, mainly through modifications in the formation of interleukin (IL)-1β, interleukin 2 (IL-2), interleukin 8 (IL-8), interleukin 10 (IL-10), interleukin 12 (IL-12), and tumor necrosis factor alpha (TNF-α). Responses were also observed in biochemical parameters, such as reduction of xanthine oxidase, and plasma free radicals. There were also changes related to anthropometry and body composition, in lean body mass (LBM). Some repercussions on performance were also observed, such as an increase in Sprint time (s), and training efficacy, a decrease post-run muscular pain through the Visual Analog Score (VAS), and recovery time in hours. Conclusion: This systematic review indicates that quercetin supplementation does not improve exercise performance, but may exert positive effects on training development, which might trigger better performance as training progresses. On the inflammatory and oxidative-related parameters, just a few evidence pointed to an improved biochemical profile, wherein the slight enhancement may not justify the supplementation costs.