Elite sport performance results from the integration of metabolic, neuromuscular, biomechanical, and psychocognitive capacities within a complex adaptive biological system. In recent years, the gut microbiota has been proposed as a potential modulator of this system. The microbiota, comprising microbial communities of bacteria, archaea, fungi, and viruses that colonise the gastrointestinal tract, exerts systemic effects on energy metabolism, immune function, and inflammatory regulation. In elite athletes, these mechanisms may influence training adaptation processes, recovery quality, and resilience to physiological stress.
Research Background
Within the framework of my doctoral research conducted at the University of Verona and the University of Rome “Foro Italico” under the supervision of Prof. Attilio Parisi, in collaboration with Prof. Alessio Fasano at Massachusetts General Hospital for Children and Harvard Medical School, we have conducted a series of studies investigating the relationship between gut microbiota and athletic performance.
Our first original study adopted a longitudinal design in elite volleyball athletes, monitoring gut microbiota composition across distinct phases of the competitive season: training, competition, and recovery [1]. The longitudinal approach enabled the observation of intra-individual variation over time, reducing inter-subject variability and allowing exploration of the impact of training load, competitive stress, and seasonality. Although causal inferences cannot be definitively drawn from this design, it represents a methodological advancement over cross-sectional approaches. Complementing this, a recent systematic scoping review published in the same journal broadened the analysis of available evidence in high-level athletes, identifying possible microbiota-specific patterns, recurring methodological limitations, and future research priorities [2].
Combat Sports and Weight Management
A further systematic scoping review included eight studies encompassing 247 elite and high-level athletes competing in wrestling, MMA, judo, martial arts, and taekwondo [3]. Available evidence suggests associations among microbiota characteristics, training intensity, competitive level, rapid weight-loss practices, and pre-competition psychological states. However, taxonomic consistency across studies was limited, rendering the identification of robust, sport-specific microbial signatures premature at this stage. A practically relevant consideration is the practice of rapid weight loss. Weight losses of ≥5% within 3–7 days, typically achieved through caloric restriction and dehydration, may significantly alter microbiota composition, potentially increase inflammatory markers, and impair immune function. Such alterations may contribute to the performance decrements commonly observed in the post-weigh-in period.
Microbiota-Targeted Interventions
Preliminary trials suggest potential benefits of probiotic and prebiotic interventions on gastrointestinal symptoms, aerobic performance, and psychological fatigue [3,4]. However, small sample sizes and methodological heterogeneity across studies limit the generalisability of these findings. As the evidence base expands, targeted supplementation with prebiotics, probiotics, postbiotics, and synbiotics may emerge as an optimal strategy for modulating the gut microbiota in elite athletes, although diet remains the primary modulator [2].
Practical Implications
The gut microbiota is a dynamic biological system that responds to the same stressors that sport practitioners already address daily: training load, diet, recovery, and psychological stress. Its management may therefore represent an additional factor in optimising athlete performance and health. While preliminary, current evidence offers several operational indications. From a nutritional standpoint, a diversified diet rich in dietary fibre (25–30 g/day), plant-derived polyphenols, and fermented foods such as yoghurt, kefir, and sauerkraut is associated with greater microbial richness and diversity [5]. These characteristics, in turn, are correlated with improved inflammatory and immunological profiles in athletes. This does not represent an unconventional approach, but rather dietary strategies already recommended for general health, with additional potential relevance from a microbiome perspective.
Regarding training programming and periodisation, inadequately periodised training loads appear to be associated with alterations in intestinal permeability and microbial composition. This suggests that gut health could serve as a training-load monitoring indicator alongside resting heart rate and biochemical markers of fatigue. In weight-category sports, rapid weight reduction warrants specific evaluation from an intestinal health perspective, beyond the well-established metabolic and hormonal effects. Evidence suggests potential alterations in the microbiota with consequences for immune function and post-weigh-in performance. A gradual, planned approach to weight management with attention to nutritional quality during the restriction phase may help mitigate these effects.
Finally, regarding supplementation with prebiotics, probiotics, postbiotics, and synbiotics, the current recommendation is one of caution. Preliminary findings are encouraging, but the heterogeneity of strains, dosages, and protocols studied renders standardised interventions premature. The choice of a probiotic should be guided by strain-specific evidence and contextualised to the individual characteristics of the athlete.
Future Perspectives
Research on sports microbiomes is still in an early stage of scientific maturity. Questions regarding causality, transferability across sport disciplines, biological sex, and age groups remain open. From a methodological standpoint, microbiome analysis techniques are rapidly evolving and will, in the coming years, enable increasingly detailed and functional characterisation of microbial communities in athletes. The long-term objective is to integrate microbiota modulation into personalised athletic preparation strategies not as an isolated element, but as part of an integrated approach that considers nutrition, training load, and recovery as interconnected variables within a single biological system. Future research may enable a more comprehensive characterisation of sport-specific microbial profiles, whose collective genetic potential may represent an underexplored resource for optimising elite athletic performance.
Bibliography
Carlone J, Giampaoli S, Alladio E, et al. Dynamic stability of gut microbiota in elite volleyball athletes: microbial adaptations during training, competition and recovery. Front Sports Act Living. 2025;7:1662964. Published 2025 Sep 3. doi:10.3389/fspor.2025.1662964
Carlone J, Parisi A, Fasano A. The performance gut: a key to optimizing performance in high-level athletes: a systematic scoping review. Front Sports Act Living. 2025;7:1641923. Published 2025 Oct 20. doi:10.3389/fspor.2025.1641923
Carlone J, Rossi C, Bianco A, Drid P, Parisi A, Fasano A. Exploring the Gut Microbiome in Combat Sports: A Systematic Scoping Review. Sports (Basel). 2026;14(1):19. Published 2026 Jan 4. doi:10.3390/sports14010019
Mohr AE, Jäger R, Carpenter KC, et al. The athletic gut microbiota. J Int Soc Sports Nutr. 2020;17(1):24. Published 2020 May 12. doi:10.1186/s12970-020-00353-w
Mancin L, Burke LM, Rollo I. Fibre: The Forgotten Carbohydrate in Sports Nutrition Recommendations. Sports Med. 2025;55(5):1067-1083. doi:10.1007/s40279-024-02167-1
Author Bio
Junior Carlone is a PhD candidate at the Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, and the Department of Movement, Human and Health Sciences, University of Rome “Foro Italico” (Prof. Attilio Parisi). He was a visiting researcher at Massachusetts General Hospital for Children and Harvard Medical School (Prof. Alessio Fasano). His research investigates the bidirectional relationship between gut microbiota and athletic performance in elite athletes.
LinkedIn: https://www.linkedin.com/in/junior-carlone-503b44159/
ResearchGate: https://www.researchgate.net/profile/Junior-Carlone?ev=hdr_xprf
ORCID: https://orcid.org/0009-0008-4042-6109