Effects of Probiotics and Diet Management in Patients With Irritable Bowel Syndrome: A Systematic Review and Network Meta-analysis

CONTEXT: The efficacy of probiotics and diet management in irritable bowel syndrome (IBS) is controversial, and their relative effectiveness remains unclear. OBJECTIVE: This study aimed to evaluate the effects of probiotics, diet management, and their combination on IBS. DATA SOURCES: PubMed, Embase, Cochrane, and Web of Science were searched from inception to July 10, 2023, for relevant studies, including symptom relief, IBS-symptom severity score (-SSS), and IBS-quality of life measure (-QOL). DATA EXTRACTION: Two investigators independently performed the data extraction and quality assessment. DATA ANALYSIS: A network meta-analysis was performed using a frequentist approach and a random-effects model to estimate the relative risk (RR) and 95% CI. RESULTS: Forty-four articles were eligible for this study. In relieving IBS symptoms, compared with a sham diet, a low-fermentable oligosaccharide, disaccharide, monosaccharide, and polyols (low-FODMAP) diet (RR: 3.22; 95% CI: 1.70-6.26) and low-FODMAP diet combined with probiotics (RR: 17.79; 95% CI: 3.27-112.54) significantly relieved IBS symptoms. The control group showed significantly lower effectiveness than the probiotics group (RR: 0.47; 95% CI: 0.32-0.69). According to the surface under the cumulative rank curve (SUCRA), a low-FODMAP diet combined with probiotics (80.4%) had the best effect in relieving IBS symptoms, followed by a low-FODMAP diet (70.8%), probiotics (65.1%), and a gluten-free diet (54.3%). In reducing the total IBS-SSS, the low-FODMAP diet (90.5%) was the most effective, followed by the low-FODMAP diet combined with probiotics (76.6%), probiotics alone (62.3%), and gluten-free diet (28.3%). In reducing total IBS-QOL, probiotics (72.1%) ranked first, followed by gluten-free (57.0%) and low-FODMAP (56.9%) diets. Probiotics (34.9%) were associated with the lowest risk of adverse effects. CONCLUSION: A low-FODMAP diet combined with probiotics is most effective in relieving IBS symptoms. A low-FODMAP diet is the most recommended diet for alleviating IBS severity, and probiotics were associated with improving the QOL of patients with IBS, with the fewest adverse events. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42024499113.