Gut Microbial Flora, Prebiotics, and Probiotics in IBD: Their Current Usage and Utility

Gut microbiota plays a crucial role in triggering, maintaining, and exacerbating IBD. Specific microbes can be overrepresented in IBD while others seem to be protective. A decrease in microbial biodiversity has been found in mucosa and feces of IBD patients, together with an increase of fungi. Pre- and probiotics could represent a valid armamentarium to modulate gut microbiota and, probably, to cure IBD. Current evidences, however, show a clear clinical efficacy of some families of probiotics only in pouchitis and ulcerative colitis but not in Crohn’s disease. This efficacy has been prevalently associated to mild disease and seems to have a better role in maintenance of remission compared to induction of remission. Further studies are necessary to better characterize the exact role of probiotics in IBD, their specific mechanisms of actions, including a direct effect on mucosal homeostasis or healing. Since probiotics are becoming a legitimate therapeutic option, it is necessary to determine which probiotic strains have the greatest efficacy, whether they are more effective alone, or in conjunction with other pro- or prebiotics, and what is their half-life in the gastrointestinal tract. On the base of these data, frequency of administration and dose could be exactly calculated.