S804 Impact of Probiotic/Synbiotic Supplementation on Post-Bariatric Surgery Anthropometric and Cardiometabolic Outcomes: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials

Introduction: Bariatric surgery improves weight and metabolic health in individuals with severe obesity; however, challenges like gut dysbiosis and nutrient deficiencies persist postoperatively. Probiotic supplementation may enhance recovery by modulating gut microbiota. This updated meta-analysis aimed to assess the effects of probiotics/synbiotics on metabolic, anthropometric, and nutritional outcomes after bariatric surgery. Methods: A systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted by searching PubMed, Scopus, Web of Science, and Cochrane CENTRAL through December 2024. Eligible studies included adult patients who underwent bariatric surgery and compared probiotics or synbiotics (combinations of probiotics and prebiotics) with placebo. Meta-analyses were performed using mean differences (MD) with 95% confidence intervals (CIs) for continuous outcomes. Subgroup analyses were conducted based on type of bariatric surgery, timing of intervention, and probiotic formulation. All statistical analyses were performed using R software version 4.3.3. Results: Thirteen RCTs involving 809 patients were included in the analysis. Probiotic use significantly reduced body mass index BMI (MD = 0.99, 95% CI: 0.88 to 1.09), HbA1c (MD = –0.19%, 95% CI: –0.36 to –0.01), triglycerides (MD = –16.56 mg/dL), aspartate aminotransferase levels (MD = –3.68 U/L), while increasing alkaline phosphatase (MD = 8.12 U/L) and Vitamin D (MD = 13.68 pg/mL). Ferritin levels were significantly lower (MD = –18.89 µg/L) in the probiotics group. Subgroup analysis showed enhanced benefits in patients undergoing mini-gastric bypass, with perioperative or synbiotic interventions specifically improving triglycerides, total cholesterol, and HbA1c. Conclusion: Probiotics may contribute to modest yet statistically significant improvements in BMI reduction, glycemic control, lipid profile, liver enzyme levels, and vitamin D status following bariatric surgery. These findings highlight the potential of probiotics or synbiotics as valuable adjunct therapies in the postoperative management of bariatric patients. However, larger, high-quality randomized controlled trials are needed to validate these outcomes and establish their long-term efficacy and safety.