Systematic review of randomized controlled trials of probiotics, prebiotics, and synbiotics in inflammatory bowel disease

BACKGROUND Probiotics are microorganisms that are ingested either in combination or as a single organism in an effort to normalize intestinal microbiota and potentially improve intestinal barrier function. Recent evidence has suggested that inflammatory bowel disease (IBD) may result from an inappropriate immunologic response to intestinal bacteria and a disruption in the balance of the gastrointestinal microbiota in genetically susceptible individuals. Prebiotics, synbiotics, and probiotics have all been studied with growing interest as adjuncts to standard therapies for IBD. In general, probiotics have been shown to be well-tolerated with few side effects, making them a potential attractive treatment option in the management of IBD. AIM To perform a systematic review of randomized controlled trials on the use of probiotics, prebiotics, and synbiotics in IBD. RESULTS In our systematic review we found 14 studies in patients with Crohn's disease (CD), 21 studies in patients with ulcerative colitis (UC), and five studies in patients with pouchitis. These were randomized controlled trials using probiotics, prebiotics, and/or synbiotics. In patients with CD, multiple studies comparing probiotics and placebo showed no significant difference in clinical outcomes. Adding a probiotic to conventional treatment improved the overall induction of remission rates among patients with UC. There was also a similar benefit in maintaining remission in UC. Probiotics have also shown some efficacy in the treatment of pouchitis after antibiotic-induced remission. CONCLUSIONS To date, there is insufficient data to recommend probiotics for use in CD. There is evidence to support the use of probiotics for induction and maintenance of remission in UC and pouchitis. Future quality studies are needed to confirm whether probiotics, prebiotics, and synbiotics have a definite role in induction or maintenance of remission in CD, UC, and pouchitis. Similar to probiotics, fecal microbiota transplantation provides an alternate modality of therapy to treat IBD by influencing the intestinal flora.