High-dose Dietary Fibre Supplementation Enhances the Gut Microbiome, Health, and Athletic Performance of College Basketball Players

Background: Prolonged or intense exercise can disrupt gastrointestinal (GI) function and gut microbiota, impairing athletic performance. Dietary fibre supplementation may enhance gut microbiota diversity, improve body composition, and promote recovery in athletes. This study aimed to explore the effects of dietary fibre supplementation at two doses for 8 weeks on these aspects in college basketball players. Methods: Twenty male college basketball players (aged 17–25 years) were randomly assigned to a high-dose group (HDG; 10 participants; 6.84 g/day dietary fibre) or a low-dose group (LDG; 10 participants; 3.24 g/day dietary fibre). The participants consumed fibre-enriched meals daily while maintaining their regular training schedules. The outcome measures included gut microbiota diversity (metagenomic sequencing), body composition, fatigue recovery markers, glucose and lipid metabolism, and athletic performance. Statistical analyses included paired and independent t tests for within- and between-group comparisons and Spearman’s correlation analysis to assess the relationships between gut microbiota and biochemical markers. Results: One participant in the high-dose group withdrew, and nineteen ultimately completed the study. Both groups showed significant within-group improvements (p < 0.05) in body weight (HDG: –2.77 ± 0.76 kg; LDG: –2.40 ± 0.67 kg), body fat percentage (HDG: –1.87 ± 0.69; LDG: –1.49 ± 0.45), cortisol (HDG: –6.79 ± 4.26 μg/dL; LDG: –4.5 ± 4.84 μg/dL), maximum power (HDG: 27.16 ± 9.77 W; LDG: 14.50 ± 9.43 W), maximal oxygen uptake (HDG: 8.78 ± 0.97; LDG: 6.90 ± 1.37), and half-court triangle run times (HDG: –0.48 ± 0.36 s; LDG: –0.25 ± 0.20 s). Meanwhile, fasting blood glucose significantly decreased (0.91 ± 0.55 mmol/L; p = 0.001), and the gut microbiome changes were more stable in the HDG, whereas the LDG presented greater shifts in microbial diversity. No significant between-group differences were observed. Conclusions: Dietary fibre supplementation improved the gut microbiome composition, body composition, fatigue recovery, and athletic performance of college basketball players, regardless of dosage. Further studies are needed to evaluate higher doses and specific fibre types.