Interaction between nutrition, intestinal flora and the gastrointestinal immune system.

The intestinal mucosa is the biggest surface of the body, which is constantly in close contact with a high number of different bacteria and food antigens. Furthermore it has to absorb nutrients and in this process to differentiate between those molecules which have to pass the mucosal barrier and be taken up as nutrition and those molecules and organisms which have to be kept out to maintain the sterile condition in the organism. This is a complex function which is regulated by different layers of the intestinal barrier as well as specific transport systems.