RESUMEN
Probiotics may be registered as food supplements or drugs. This article summarizes differences in European regulations of probiotics registered as food supplements and drugs, as well as issues related to the quality of probiotic products. For registration as a drug, the European Medicines Agency demands extensive and detailed quality, efficacy and safety evidence; whereas compulsory analyses requested for food supplements consist only in a nutritional analysis. As a result, the quality of those probiotics registered as drugs, compared to food supplements, is in general controlled with higher standards. Despite these differences and whatever the status of the probiotic product, its efficacy and safety has to be documented in well conducted randomized controlled trials (RCTs). Furthermore, this paper reviews recent evidence on the use of probiotics for gastrointestinal diseases, evaluating all the existing information up to January 2014. In all eligible published studies in which use of probiotics for gastrointestinal diseases were investigated and reported, no language limitations were applied. Special focus is placed on RCTs (or their meta-analyses) showing positive results, so that the findings may be applicable to everyday clinical practice. Currently, the best documented clinical areas appear to be probiotics efficacy for the treatment of acute gastroenteritis in children and for the prevention of antibiotic-associated diarrhea both in children and in adults. In other gastrointestinal conditions, some promising observations are emerging, but no definitive conclusions can be reached at present.