From yaks to yogurt: the history, development, and current use of probiotics.

The development of probiotics, which are living bacteria or yeasts used to confer a health benefit on the host, has paralleled our research in food preservation, microbiologic identification techniques, and our understanding of how the complex interactions in microbiota impact the host's health and recovery from disease. This review briefly describes the history of probiotics, where probiotic strains were originally isolated, and the types of probiotic products currently available on the global market. In addition, the uses or indications for these probiotics are described, along with the types of clinical investigations that have been done. Continuing challenges persist for the proper probiotic strain identification, regulatory pathways, and how healthcare providers can choose a specific strain to recommend to their patients.