The Impact of Probiotics and Synbiotics Supplementation on Bone Health; an Umbrella Review of Systematic Reviews and Meta-Analysis Publisher



Mazandarani M ; Lashkarbolouk N ; Ejtahed H S ; Dehghani A ; Molani Gol R ; Hasani Ranjbar S ; Larijani B
Source: SAGE Open Medicine Published:2026

Abstract

Background: The effects of probiotics and synbiotics on bone health remain uncertain due to conflicting results across existing systematic reviews and meta-analyses (SRs/MAs). Methods: PubMed/Medline, Cochrane, and Web of Science were searched through February 2025. SRs/MAs on probiotics or synbiotics for bone health were included. An umbrella review with meta-analysis of pooled effect sizes was conducted using random-effects models: Hedges’ g for bone mineral density (BMD) and muscle mass, and mean difference for muscle strength. Heterogeneity was assessed via I2, and AMSTAR2 rated confidence. PROSPERO ID: CRD42025636002. Results: Our initial search identified 930 articles (488 from PubMed/MEDLINE, 260 from Web of Science, and 182 from Cochrane). After removing duplicates and screening titles, abstracts, and full texts, sixteen systematic reviews and meta-analyses were included (with 3,245 participants), and only human studies were considered for meta-analysis. Most studies investigated Lactobacillus and Bifidobacterium strains as probiotics. Probiotics and synbiotics supplementation significantly improved BMD (Weighted mean difference (WMD) = 0.39, 95% Confidence interval (CI): 0.14, 0.63, p = 0.002), muscle mass (WMD = 0.46, 95% CI: 0.23, 0.68, p < 0.001), and muscle strength (WMD = 1.99, 95% CI: 0.42, 3.57, p = 0.013). Subgroup analyses identified BMD measurement site, number of studies, sample size, and gender as sources of heterogeneity. According to AMSTAR2, 11 reviews were rated as high confidence, one as moderate confidence, and four as low confidences. Conclusion: Probiotic/synbiotic supplementation showed modest, statistically significant BMD benefits, but with substantial heterogeneity. Findings for muscle mass and strength were based on a few meta-analyses, showed high heterogeneity, and sensitivity analyses nullified significance. Current evidence does not support clinical recommendations for probiotics/synbiotics in bone health prevention. © The Author(s) 2026. This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 License (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access pages (https://us.sagepub.com/en-us/nam/open-access-at-sage).