Abstract

Food and nutrients modulate immune functions in multiple ways. For essential nutrients, a number ofstudies have demonstrated a major regulatory role within the immune system (Calder et al. 2002). The impact of nonessential food constituents on the immune system such as prebiotics and similar complex carbohydrates, however, has not been studied thoroughly (Schley and Field 2002, Watzl et al. 2005). For proper functioning of the immune system, the intestinal flora also plays an important role. Composition and metabolic activity of the intestinal flora are directly depending on dietary constituents including prebiotics. Prebiotics (for a definition see Chapter 1) occur in plant food and isolated prebiotics have recently become a technical constituent of an increasing number of foods. Inulin (IN) and oligofructose (OF) are classified as prebiotics occurring as plant storage carbohydrates in vegetables, cereals, and fruits. Recent data indicate that prebiotics may modulate the gut-associated lymphoid tissue (GALT) as well as the systemic immune system.