Microbiome-based nutrition and the gut-muscle axis: emerging perspectives for athletic performance and recovery.

The gut microbiota has emerged as a significant regulator of exercise adaptation, recovery, and skeletal-muscle function, giving rise to the idea of the gut-muscle axis as a potential target in sports nutrition. This review summarizes current data on how microbiome-targeted nutritional approaches, such as probiotics, prebiotics, synbiotics, post-biotics, and polyphenol-rich dietary interventions, effect physiological processes related to athletic performance. Human research suggests that certain therapies may enhance endurance capacity, recuperation, gastrointestinal health, immunological function, and body composition, however, these advantages are typically strain-, formulation-, and population-specific. Further experimental evidence indicates that microbial metabolites, especially urolithins and short-chain fatty acids, may control anabolic signaling, inflammatory responses, mitochondrial function, and redox balance via pathways involving AMPK, PGC-1α, and associated molecular networks. However, there is still no direct validation of these pathways in human athletes, and the majority of mechanistic information comes from cellular and animal models. The translation of existing findings into evidence-based sports nutrition recommendations is further constrained by significant variation in study design, intervention characteristics, participant populations, and outcome measures. More robust longitudinal human investigations incorporating strain-resolved microbiome profiling, microbial metabolomics, and standardized physiological and performance outcomes are needed in order to identify effective intervention strategies and establish causal mechanisms.