Use of probiotics in gastrointestinal disorders: what to recommend?

Perturbation of bacterial microflora of the gastrointestinal (GI) tract may play an important role in the pathophysiology of some GI disorders. Probiotics have been used as a treatment modality for over a century. They may restore normal bacterial microflora and effect the functioning of the GI tract by a variety of mechanisms. Probiotics are not currently regulated and only few randomized controlled trials exist investigating their efficacy in different GI disorders. They are available in a variety of formulations and delivery systems making interpretation and comparison of studies even more difficult. The efficacy of probiotics, either as a single strain or a combination of probiotics, has been tested in antibiotic-associated diarrhea, Clostridium difficile colitis, infectious diarrhea, ulcerative colitis, Crohn's disease, pouchitis, and irritable bowel syndrome, among other disorders. Results of the studies are reviewed in this article and recommendations for probiotic use in these disorders are made. Although probiotics appear to be generally safe in an outpatient setting, the situation may be different in immunocompromised, hospitalized patients who may be at a greater risk of developing probiotic sepsis. No studies exist addressing the issue of safety specifically. Many questions regarding use of probiotics in GI disorders remain to be answered in future studies, such as most optimal doses, duration of treatment, physiological and immunological effects, efficacy of specific probiotics in specific disease states, and safety in debilitated patients.