ABSTRACT
Probiotics, as dened by the FAO and the WHO in a joint consensus document, are live microorganisms that confer a health benet on the host when administered in adequate amounts. Probiotics have been studied in the treatment and prevention of many gastrointestinal and nongastrointestinal diseases and their role in promoting health is now supported by many double-blind placebocontrolled human trials. Probiotics show convincing evidence in different elds as follows:
• Prevention of respiratory tract infections • Prevention and therapy of allergy • Treatment and prevention of gastrointestinal infections and antibiotic-associated diarrhea • Treatment of Inammatory bowel disease • Prevention and treatment of Functional gastrointestinal disorders (FGIDs)
In order to understand the mechanisms by which probiotics are involved in the maintenance of intestinal microbiota and, as consequence, are useful in confer a health benets, the concepts of intestinal barrier function and dysbiosis, immunology system, and gut-brain axis have to be introduced prior to describe the role of probiotics in specic diseases.
