Signatures in the gut microbiome of German elite athletes: insights from a matched-subgroup analysis

Elite athletes undergo intense physical training and experience substantial physiological stress, which could affect the composition and function of their gut microbiome. This study compared the gut microbiomes of 148 German junior and senior elite athletes with those of 108 healthy adults to identify taxonomic and functional features associated with elite athletic status. Group comparisons were conducted between healthy adults, senior athletes, and junior athletes, and a matched-subgroup analysis was performed in adults only, controlling for age, sex, body mass index, and dietary pattern. Significant differences in taxonomic composition were observed between athletes and healthy adults. Healthy adults exhibited greater microbial evenness and diversity than junior athletes, whereas senior athletes displayed higher microbial richness. Principal coordinate analysis revealed distinct clustering by athletic status. Linear discriminant analysis effect size identified taxa such as Escherichia-Shigella as being enriched in athletes. Predictive metagenomic profiling (PICRUSt2) indicated differences in microbial functional potential between adult athletes and matched controls, including pathways related to amino acid metabolism, glycolysis, fatty acid β-oxidation, and quinone biosynthesis. Together, these findings demonstrate distinct taxonomic and predicted functional microbiome signatures associated with elite athletic status.