Abstract
The entire gastrointestinal tract is populated by microorganisms, with the colon being the most populated area of the tract. The sterile newborn gut is colonized at birth and thereafter; this contributes to the normal development of its gut. The bacteria found in the gastrointestinal tract can be classified as either beneficial or harmful to the host, their metabolism contributing largely to this classification; saccharolytic species are considered beneficial as opposed to proteolytic species, which are considered harmful. Prebiotics can stimulate the growth of specific bacteria. They are nondigestible carbohydrates that are selectively fermented by health-promoting bacteria; in other words, because the host cannot digest these carbohydrates, they reach the colon intact, where they are fermented by beneficial bacteria. The functionality of these carbohydrates is dependent on their chemistry and the host health status. Inulin, fructooligosaccharides, and galactooligosaccharides are accepted prebiotics; however, others such as soya-oligosaccharides and xylooligosaccharides are promising prebiotics.