Prebiotic

A prebiotic was first defined as a "non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, and thus improves host health". [Gibson GR, Roberfroid MB, "Dietary modulation of the human colonic microbiota: introducing the concept of prebiotics" J Nutr 1995;125:1401–12.] However, a prebiotic nature has been attributed to many food components without due consideration to the criteria required. In particular, almost every food oligosaccharide and polysaccharide (including dietary fiber) has been claimed to have prebiotic activity, but not all dietary carbohydrates are prebiotics. There is, therefore, a need to establish clear derivatives for classifying a food ingredient as prebiotic. Such classification requires a scientific demonstration that the food component or ingredient:

# resists host digestion, absorption and adsorption processes;
# is fermented by the microflora colonising the gastrointestinal system;
# selectively stimulates the growth and/or the activity of one or a limited number of bacteria within the gastrointestinal system.

As with most functional foods or ingredients [Diplock AT, Aggett PJ, Ashwell M, Bornet F, Fern EB, Roberfroid MB, "Scientific concepts of functional foods in Europe: consensus document", Br J Nutr 1999;81:S1–S27.] , the final demonstration must be carried out in vivo, either humans or in domestic animals or pets through appropriate clinical feeding trials. The methodologies used should be validated and supported by sound scientific approaches. Although each of these criteria is equally important, the third, concerning the selective stimulation of growth and/or activity of one or a limited number of bacteria, remains the most important and probably the most difficult to fulfill. This leads to a consideration of fermentable substrates in the human diet, availability for the microflora and selective metabolism. The following oligomers have been suggested as having prebiotic potential: [Gibson GR, Berry Ottaway P & Rastall RA, "Prebiotics: New Developments in Functional Foods", Oxford: Chandos Publishing Limited, 2000.]

* Lactulose
* Fructo-oligosaccharides
* Galacto-oligosaccharides
* Soybean oligosaccharides
* Lactosucrose
* Isomalto-oligosaccharides
* Gluco-oligosaccharides
* Xylo-oligosaccharides
* Isomaltulose

ee also

*
* Polysaccharide

References