Systematic review and meta-analysis on probiotics for glycemic control in pediatric type 1 diabetes

To evaluate the efficacy and safety of gut microbiota-modulating interventions in children and adolescents with type 1 diabetes. A systematic review and meta-analysis was conducted according to PRISMA 2020. PubMed/MEDLINE, Scopus, Web of Science, and CENTRAL were searched from inception to 28 February 2026 for randomised controlled trials of oral probiotics, prebiotics, or synbiotics in participants aged ≤ 19 years with type 1 diabetes. Primary outcomes were glycated haemoglobin, fasting blood glucose, total daily insulin dose, and C-peptide. Immune-inflammatory, microbiota-related, intestinal permeability, and safety outcomes were narratively synthesised. Twelve randomised controlled trials involving 808 paediatric participants were included. Interventions varied in formulation, dose, and duration. Pooled analyses showed significant reductions in glycated haemoglobin and fasting blood glucose, whereas no significant effects were found for total daily insulin dose or C-peptide. Immune-inflammatory, microbiota-related, and intestinal permeability outcomes suggested possible benefits, but reporting was inconsistent and quantitative pooling was not feasible. Overall, the evidence was limited by substantial clinical and methodological heterogeneity. Conclusion: Gut microbiota-modulating interventions may improve glycaemic control in children and adolescents with type 1 diabetes, particularly glycated haemoglobin and fasting blood glucose. However, current evidence is insufficient to support any specific formulation, dose, or duration, and larger well-designed paediatric trials are still needed. What is Known: • Gut microbiota-modulating interventions are biologically plausible adjunctive strategies in paediatric type 1 diabetes. • Earlier paediatric reviews included few randomised trials and reported inconsistent glycaemic findings. What is New: • This updated review included 12 randomised controlled trials involving 808 children and adolescents. • It adds a structured synthesis of immune-inflammatory, microbiota/barrier, metabolite-related and safety outcomes beyond glycaemic endpoints.