Gut Microbiota Modulation by a Prebiotic-and Probiotic-Enriched Diet in a High-Performance Weightlifter: A Case Report

Introduction: The gut microbiota has been linked to metabolism and immune regulation, and its relevance to performance is now being explored. Prebiotic- and probiotic-rich diets are commonly used in practice to support gut health, but their effects in elite strength athletes are still not well characterized. This case report presents a five-week, pre–post case study describing microbiota changes during a structured food-based intervention in a high-performance weightlifter. Case Presentation: A high-performance male weightlifter completed a five-week dietary intervention enriched with prebiotic and probiotic components, including resistant starch sources (oats, legumes, cold potatoes), fermented foods (kefir, yogurt, sauerkraut), and fiber-rich vegetables (broccoli, spinach, beets). Fecal samples were collected before and after the intervention. Samples were profiled by 16S rRNA gene sequencing (V3–V4, Illumina MiSeq), and taxa were assigned with SILVA 138.1; alpha- and beta-diversity were summarized with standard metrics. The intervention was associated with a shift in community composition, showing an increased relative abundance of butyrate- and propionate-producing taxa (Faecalibacterium, Bifidobacterium, Phascolarctobacterium, Sutterella, Lacticaseibacillus) and a reduction in pro-inflammatory and methanogenic groups (Howardella, Bilophila, Methanobrevibacter). Bray–Curtis distances separated pre- and post-intervention profiles, indicating distinct community structures after the diet. Conclusion: This case report illustrates that a short-term, food-based prebiotic- and probiotic-enriched diet may lead to detectable changes in microbiota composition over a short timeframe in a weightlifter. The observed shifts toward short-chain fatty acid–producing and anti-inflammatory taxa suggest a potential role for targeted dietary strategies in supporting gut microbial balance and metabolic resilience during intensive training of the athlete. In the case report, causal inference is limited, and findings may not generalize to other athletes; we highlight the need for controlled, longitudinal studies in larger athletic cohorts.