Probiotic Potential in Irritable Bowel Syndrome and Inflammatory Bowel Disease: A Comprehensive Systematic Review

Irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) are prevalent gastrointestinal disorders with significant global prevalence. Conventional treatments often have adverse effects, prompting interest in probiotics as alternative therapies. This systematic review assesses the efficacy of probiotics in managing symptoms and improving outcomes in adult patients with IBS and IBD. A comprehensive search was conducted across databases such as PubMed, Cochrane Library, and Google Scholar and registers ClinicalTrials.gov and International Standard Randomized Controlled Trial Number (ISRCTN). Using targeted keywords, studies on probiotic efficacy in adult IBS and IBD patients were identified. Data screening, extraction, and quality assessment using the Cochrane Risk of Bias 2 (RoB 2) tool for evaluating randomized controlled trials (RCTs) and Newcastle-Ottawa Scale (NOS) for cohort studies were rigorously performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. From the initial 22,037 references, 18 randomized control trials and two observational studies encompassing 2,675 adults, aged 18-76 years, were deemed eligible. The efficacy of probiotics for IBS and IBD is variable. While some IBS trials show symptom improvement, the results are inconsistent, likely due to the diversity of probiotic strains and patient populations studied. In contrast, probiotics demonstrate more consistent benefits for ulcerative colitis (UC) in IBD, particularly with specific formulations like the De Simone combination. However, probiotics' effects on Crohn's disease (CD) remain less clear, highlighting the need for further research to optimize probiotic regimens and understand their differential effects across the spectrum of IBS and IBD.