Prebiotics are non-digestible food ingredients that beneficially affect the host by selectively stimulating the growth and/or activity of one or a limited number of beneficial bacteria in the gastro-intestinal tract, and thus improve host health. Prebiotics do not adversially affect the animal  health

Among food ingredients, non-digestible carbohydrates e.g. oligosaccharides, some peptides and proteins, and certain lipids are considered as potential prebiotics.