Nutrological aspects of polyphenols and gut microbiota in sports performance: a systematic review

Introduction: In the context of nutrology and sports performance, the focus for intake in athletes and physically active individuals has been directed to the main class of polyphenols. Interest in a personalized approach is increasing in sports to maximize each individual's athletic ability in endurance and strength sports. Polyphenols represent a heterogeneous class of compounds with marked antioxidant and anti-inflammatory properties. The impact of the gut microbiota on the bioavailability and activity of polyphenols is highlighted. Objective: It was to carry out a systematic review to highlight the main relationships between polyphenols, gut microbiota, and sports performance. Methods: The systematic review rules of the PRISMA Platform were followed. The research was carried out from May to July 2023 in Scopus, PubMed, Science Direct, Scielo, and Google Scholar databases. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: A total of 115 articles were found, and 81 articles were evaluated in full and 76 were included and developed in this systematic review study. Considering the Cochrane tool for risk of bias, the overall assessment resulted in 6 studies with a high risk of bias and 10 studies that did not meet GRADE. As a result and conclusion, it was shown that the metabolic mechanisms favored by polyphenols improve sports performance, improve cardiometabolic functions, reduce recovery times and post-exercise pain, maintain a low degree of oxidative stress, and avoid unregulated inflammatory processes. Thus, polyphenols are able, through their interaction with the gut microbiota, to favor the proliferation of bacterial genera of great importance for metabolic and cognitive functions, such as Akkermansia, Lactobacilli, and Bifidobacteria. Gut microbiota metabolizes polyphenols in the colon to produce small bioactive molecules that exert epigenetic mechanisms on biochemical pathways modulating gene expression. Polyphenols have multiple biological effects, and future exercise studies should be appropriately and specifically designed to determine the physiological interactions between exercise and the selected supplement, rather than just considering performance.