Probiotics: an update

Abstract

Humans harbor vast numbers of microorganisms on the skin, in the mouth, and in the gastrointestinal tract. The gastrointestinal tract alone is home to more than 500 different bacterial species, some of which have important health functions in stimulating the immune system, protecting the host from invading bacteria and viruses, and aiding digestion. Nobel laureate Elie Metchnikoff proposed in the early 1900s that the long life of Bulgarian peasants resulted from their consumption of fermented milk products. The term “probiotic” was first used in 1965, and, in 2002, Marteau defined probiotics as microbial preparations or components of microbial cells that have a beneficial effect on health and well-being. This chapter examines the use of antibiotics, immunosuppressive therapy, irradiation, and other various means of treatment that may cause alterations in the normal human flora. It explores the idea of introducing beneficial bacterial species into the GI tract as an attractive option to reestablish microbial equilibrium and prevent disease.