As the composition and functions of the gastrointestinal microbiota are revealed, their critical role in health and disease will be defined. These discoveries open new therapeutic avenues and have the potential to explain the benefits of probiotics. Although many products masquerade as probiotics, only those that contain live organisms and have been shown in high-quality human studies to confer a health benefit can actually claim this title. We need more high-quality trials of probiotics in gastrointestinal disorders as well as laboratory investigations of their mechanism of action. Ultimately, such studies should allow us to understand, not only who responds, but why.
Curr Opin Gastroenterol. 2013;29(2):184-189. © 2013 Lippincott Williams & Wilkins