Pro- and prebiotics - the tasty guardian angels?

It is generally accepted that the bacterial community resident in the human intestinal tract has a major impact on gastrointestinal function and there by on human health and well-being. Considerable efforts have been made to i nfluence the intestinal microbiota by dietary means in such a way that the health of the host is beneficially affected. Pro- and prebiotics are food p roducts that are specially designed for this purpose. Parallel to the incre ase in the acceptance of such products by the consumer, the scientific inte rest in the mechanisms underlying their presumed effects, such as pathogen inhibition, immune modulation or anti-carcinogenicity, has grown continuous ly in recent years. Some of these effects have been established by several independent studies, but others are still controversial. This review relate s the health claims made for the pro- and prebiotic food products to the fa cts established by in vivo and in vitro studies. The assessment of pro- and prebiotic effects on the microbial gut ecosystem is highly improved and fa cilitated by the application of molecular methods. Biotechnological aspects of the production of pro- and prebiotics are discussed.