A prebiotic is a non-digestible food ingredient that benefits 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, G.R. and Roberfroid, M.B. 1995. Journal of Nutrition). Some of the more common commercially available prebiotics are resistant maltodextrin, polydextrose and inulin. Prebiotics are fermented by bacteria into short-chain fatty acids (SCFA), the proliferation of which decreases pH.
“Prebiotics benefit both the bacteria in the product and in the colon,” explains Hilary Hursh, a food and nutrition scientist at an inulin supply house. A study conducted by her company measured the viability and vitality of bacteria in symbiotic products (products containing both prebiotics and probiotics) using simulated digestion. In such products, more bacteria survived through the product's shelflife and simulated digestion, she summarizes.