Effects of probiotic interventions on infant immunity: a systematic review and meta-analysis

Effects of probiotic interventions on infant immunity: a systematic review and meta-analysis | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 17 June 2025 V1 Latest version Share on Effects of probiotic interventions on infant immunity: a systematic review and meta-analysis Authors : Yihenew Million Yeshtila 0000-0002-3941-277X [email protected] , Nerissa Bowcock , and Steven Leach Authors Info & Affiliations https://doi.org/10.22541/au.175016369.91679056/v1 201 views 97 downloads Contents Abstract Supplementary Material Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Background: Probiotic supplementation in infancy is increasingly used to support immune development, particularly through modulation of mucosal immunoglobulin A (IgA) and systemic cytokines. However, the overall immunological impact of probiotics in infants remains uncertain. Methods: We conducted a systematic review and meta-analysis of randomised controlled trials (RCTs) from 2000 to 2025, assessing the effects of oral probiotic supplementation on faecal IgA and cytokine levels in infants. Random-effects models were used to estimate pooled effects. IgA outcomes were analysed using weighted mean differences (WMD), and cytokine outcomes (reported as medians) were pooled using the quantile estimation (QE) method. Results: Forty-two RCTs were included: 24 reporting IgA and 18 reporting cytokine outcomes. Seven IgA and eight cytokine studies were eligible for meta-analysis. The pooled effect of probiotics on faecal IgA was not statistically significant (WMD = 87.54 µg/g; 95% CI: −408.05 to 583.12; I 2 = 89%). However, after removing one outlier, the effect became significant (WMD = 421.36; 95% CI: 161.31-681.41; I 2 = 0%). Cytokine meta-analyses (IL-10, IL-6, TNF-α, IFN-γ) showed no consistent effects, though individual studies indicated increases in IL-10 and reductions in TNF-α and IL-17A. Narrative synthesis highlighted heterogeneity by strain, feeding mode, and measurement timing. Conclusion: Probiotics may modestly enhance mucosal immunity in infancy, as shown by increased faecal IgA in sensitivity analysis. Systemic cytokine responses remain inconsistent. These findings support the immunomodulatory potential of probiotics in early life and underscore the need for standardised outcomes and extended follow-up in future trials. Supplementary Material File (manuscript.docx) Download 175.05 KB Information & Authors Information Version history V1 Version 1 17 June 2025 Copyright This work is licensed under a Non Exclusive No Reuse License. Authors Affiliations Yihenew Million Yeshtila 0000-0002-3941-277X [email protected] University of New South Wales School of Clinical Medicine View all articles by this author Nerissa Bowcock University of New South Wales School of Clinical Medicine View all articles by this author Steven Leach University of New South Wales School of Clinical Medicine View all articles by this author Metrics & Citations Metrics Article Usage 201 views 97 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Yihenew Million Yeshtila, Nerissa Bowcock, Steven Leach. Effects of probiotic interventions on infant immunity: a systematic review and meta-analysis. Authorea . 17 June 2025. DOI: https://doi.org/10.22541/au.175016369.91679056/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. 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