PP350 - KEFIR SUPPLEMENTATION AS A FUNCTIONAL NUTRITIONAL STRATEGY FOR EXERCISE PERFORMANCE AND RECOVERY: A SYNTHESIS OF HUMAN RANDOMIZED AND CROSSOVER TRIALS

PP350

KEFIR SUPPLEMENTATION AS A FUNCTIONAL NUTRITIONAL STRATEGY FOR EXERCISE PERFORMANCE AND RECOVERY: A SYNTHESIS OF HUMAN RANDOMIZED AND CROSSOVER TRIALS

A. Da Silva^1,*, G. M. de Oliveira², F. V. Zamora³

¹Health Sciences, University of Bradford, Bradford, United Kingdom, ²Sports Medicine and Orthopedics, Harvard Medical School, Boston, United States, ³Family Medicine and Public Health, State University of Rio de Janeiro, Rio de Janeiro, Brazil

Rationale: Kefir is a probiotic-rich fermented dairy product increasingly positioned as a functional nutritional strategy capable of modulating gut microbiota, metabolic efficiency, and inflammatory responses during exercise stress. However, clinical evidence remains inconsistent if kefir supplementation enhance exercise performance, recovery, and gut-muscle axis-related physiological adaptations in adults compared to placebo.

Methods: Narrative synthesis of PubMed and Cochrane Library (2021–2026) identifying human trials on kefir and exercise outcomes. Eligible studies included randomized controlled trials and crossover designs in adult active or athletic populations. Four studies were included (2 RCTs, 2 crossover; n=68). Interventions: 200–250 mL/day kefir or standardized products, acute–28 days.  

Results: Kefir showed heterogeneous effects. In trained female athletes, 28-day supplementation increased microbial diversity and enriched Akkermansia and Faecalibacterium, correlating with VO2max and high-intensity gains. One crossover trial showed improved time-to-exhaustion and reduced lactate, suggesting metabolic efficiency. However, in master athletes, no improvement in 5 km performance vs placebo, but reduced GI symptoms. In young athletes, no significant recovery differences vs milk or water, though effect sizes suggested improved post-exercise power and reduced soreness. 

Conclusion: Kefir does not consistently enhance performance, but may improve physiological resilience via gut–muscle axis modulation, gastrointestinal tolerance, and partial recovery benefits. It appears more a metabolic adaptation modulator than a direct ergogenic aid. Future well-powered RCTs are needed to define its clinical role in sports nutrition.

References: DOI:10.3390/nu16050717. DOI:10.3390/metabo11030136. DOI:10.3390/nu17030512. DOI:10.1039/d5fo05127d

Disclosure of Interest: None declared