Probiotics as Functional Dietary Interventions for Gut Health, Immune Modulation, and Overall Well-Being: A Systematic Review.

BACKGROUND: The pediatric gut microbiome influences immune maturation, neurodevelopment, and disease susceptibility. Probiotic supplementation has been investigated across multiple childhood conditions, yet strain-specific efficacy remains inconsistent. OBJECTIVE: The objective of this review is to systematically evaluate strain-specific probiotic interventions in children and assess clinical efficacy, safety, and mechanistic pathways. METHODOLOGY: A systematic review was conducted following PRISMA 2020 guidelines. PubMed, Scopus, and Web of Science were searched for studies (2006-2024). RESULTS: Strong evidence supports Lactobacillus rhamnosus GG and Saccharomyces boulardii for acute diarrhea. Mixed strains show moderate benefit in atopic dermatitis. Adjunct probiotic therapy improves Helicobacter pylori eradication rates. Evidence in asthma and autism spectrum disorder remains preliminary. CONCLUSION: Significant heterogeneity in strains, dosing, and study design limits generalizability. Probiotic efficacy in pediatrics is strain and condition-specific. Standardized RCTs and precision microbiome approaches are required.