[Intestinal microbiote of athletes]

The intestinal microbiota, due to new data on its functions obtained in the last decade, has become a new target point of influence on the organism. However, nowadays knowledge about the possible impact of physical activity and sports on the composition of the gut microbiota and, as a result, on the organism is limited. The aim of this review was to summarize current knowledge about the gut microbiota of healthy people with different levels of physical activity (from athletes to physically inactive people), and to identify patterns in the composition of the microbiota of various surveyed groups. Material and methods. A systematic search was carried out in electronic databases including EMBASE, MEDLINE, Web of Science, Google Scholar and eLIBRARY. The search process was carried out using keywords and logical operators. We included the following studies in our review: a) crossover studies comparing the gut microbiome of subjects with different physical activity; b) studies involving healthy adult women and men (18-45 years old); c) studies written in English and Russian. We excluded studies containing dietary changes, consumption of probiotics or prebiotics, and studies of physical activity in sick people. Results and discussion. Total 743 articles were received, of which 14 articles fully met the search criteria, and 101 articles partially corresponded. An analysis of the data from these studies indicated noticeable differences in the microbiota between athletes and people leading an sedentary lifestyle: the athletes had a greater α-diversity of the microbiota, while the level of microorganisms of the phylum Bacteroidetes was reduced; Akkermansiaceae and Faecalibacterium bacteria are elevated in athletes and people with active lifestyles. Different levels of physical activity in physically active people according to the levels of cardiorespiratory endurance did not affect the level of α- and β-diversity. When analyzing the effect of loads on the microbiota in various sports disciplines and skill levels, a connection was found with an increase in α-diversity in professionals and highly qualified athletes, with the relative content of series of bacteria (Methanobrevibacter smithii in professional cyclists; Parabacteroides, Phascolarctobacterium, Oscillibacter, Bilophila, Megasphaera in athletes of high martial arts qualifications of wushu; Eubacterium rectale, Polynucleobacter needarius, Faecalibacterium prausnitzii, Bacteroides vulgatus, Gordonibacter massiliensis in athletes of international level of various sports), and certain genera of bacteria have been identified (Parabacteroides, Phascolarctobacterium, Besilibacterium). Conclusion. The data obtained indicate a higher relative proportion of microbiota effective members, which are involved in the fermentation of complex polysaccharides and the production of short-chain fatty acids such as Faecalibacterium prausnitzii, Eubacterium hallii, Phascolarctobacterium, Eubacterium rectale, and Methanobrevibacter smithii, which increases the fermentation efficiency of many bacterial taxa in the gut by using hydrogen gas (H₂) and formate to reduce carbon dioxide (CO₂) to methane. There is a need to study other members of the microecological community, leading to a better understanding of the adaptation of the gut microbiota to levels of physical activity and its potentially positive effects on metabolism and endurance.