RT Journal Article SR Electronic T1 An update on the use and investigation of probiotics in health and disease JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 787 OP 796 DO 10.1136/gutjnl-2012-302504 VO 62 IS 5 A1 Mary Ellen Sanders A1 Francisco Guarner A1 Richard Guerrant A1 Peter R Holt A1 Eamonn MM Quigley A1 R Balfour Sartor A1 Philip M Sherman A1 Emeran A Mayer YR 2013 UL http://gut.bmj.com/content/62/5/787.abstract AB Probiotics are derived from traditional fermented foods, from beneficial commensals or from the environment. They act through diverse mechanisms affecting the composition or function of the commensal microbiota and by altering host epithelial and immunological responses. Certain probiotic interventions have shown promise in selected clinical conditions where aberrant microbiota have been reported, such as atopic dermatitis, necrotising enterocolitis, pouchitis and possibly irritable bowel syndrome. However, no studies have been conducted that can causally link clinical improvements to probiotic-induced microbiota changes. Whether a disease-prone microbiota pattern can be remodelled to a more robust, resilient and disease-free state by probiotic administration remains a key unanswered question. Progress in this area will be facilitated by: optimising strain, dose and product formulations, including protective commensal species; matching these formulations with selectively responsive subpopulations; and identifying ways to manipulate diet to modify bacterial profiles and metabolism.