Effect of probiotic intake on athletic ability in healthy people: a systematic review and Bayesian meta-analysis

TL;DR

Probiotics may modestly improve athletic performance, especially endurance, in healthy adults, with medium doses showing the most consistent benefits.

Contribution

This study provides the first Bayesian meta-analysis on probiotics and athletic performance, clarifying dose and strain effectiveness.

Findings

Probiotic supplementation improved overall athletic performance with a small-to-moderate effect.

Endurance outcomes like aerobic endurance and VO₂max showed the clearest gains.

Medium-dose probiotics (1×10⁹ to 1×10¹¹ CFU/day) were most effective, and Lactobacillus plantarum showed significant benefits.

Abstract

To address ongoing debate about whether probiotic supplements enhance athletic performance in healthy individuals, and amid uncertainty about effective doses, strain formulations, and population-specific responses, we conducted a prospectively registered systematic review and Bayesian multi-level meta-analysis of randomized controlled trials in healthy adults.

We searched six databases from inception to 1 July 2025. Two reviewers independently completed study selection, data extraction, and risk of bias assessment using ROB. We synthesized data using hierarchical Bayesian models, and evaluated publication bias with funnel plots, Egger’s test, and significance-based diagnostics.

Twenty-one trials (N = 685) were included. Probiotic supplementation was associated with a small-to-moderate improvement in overall athletic performance [μSMD 0.38, 95% CrI 0.17 to 0.60], with the clearest gains in endurance-centric outcomes, including aerobic endurance [μSMD 0.74, 95% CrI 0.39 to 1.10] and cycle-based VO₂max [μSMD 2.21, 95% CrI 0.64 to 3.68]. Both single-strain [μSMD 0.33, 95% CrI 0.04 to 0.62] and multi-strain [μSMD 0.45, 95% CrI 0.12 to 0.79] regimens were effective. By dose, only the medium tier (1×10⁹ to 1×10¹¹ CFU per day) yielded a significant effect [μSMD 0.38, 95% CrI 0.14 to 0.62]. Significant benefits were observed in athletes [μSMD 0.38, 95% CrI 0.08 to 0.69] and in adults [μSMD 0.46, 95% CrI 0.11 to 0.81]. At the strain level, Lactobacillus plantarum showed a significant effect [μSMD 0.82, 95% CrI 0.12 to 1.50].

Probiotic supplementation is associated with a modest yet practically meaningful improvement in athletic performance among healthy adults, with benefits across single- and multi-strain products and the most consistent signal at a medium daily dose. Large multicenter trials with harmonized outcome measures are warranted to refine strain- and dose-specific recommendations. This study was registered with PROSPERO (CRD420251139260).

https://www.crd.york.ac.uk/PROSPERO/view/CRD420251139260https://www.crd.york.ac.uk/PROSPERO/view/CRD420251139260, PROSPERO (CRD420251139260).

Visual abstract titled "Effect of Probiotic Intake on Athletic Ability in Healthy People: a systematic review and Bayesian meta-analysis." Summary mentions probiotics improve athletic performance, especially endurance, with medium daily doses being most effective. Population section notes 21 RCTs with 685 participants and no health restrictions. Study Design details registration in PROSPERO and adherence to PRISMA guidelines. Data visualizations include several funnel plots and effect size graphs, highlighting statistical analyses.

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