Nutrition is an important environmental factor for the maturation of the human immune system and essential for maintaining immunological homeostasis. Based on this, a variety of food applications with medical claims are being generated by food manufacturers worldwide in order to expand the market potential of products creating interesting linkages with other market segments, such as cosmetics and pharmaceuticals. However, in addition to the health benefits, active principles of such components often remain unexplored. This book focusses on the specific interactions between food ingredients and the immune system along the entire immune defense response. Starting from the immune barrier, through the innate and adaptive immune response, to active limitation and termination, all major mechanisms of the immune response are addressed and different biochemical, cellular and genetic interactions of components of our diet are discussed. The book presents a wealth of disease patterns for which nutritional factors are relevant and thereby provides indications for potential intervention strategies. In addition, associated food-technological aspects are discussed.  Being the first of its kind, this book provides an overview of the variety of functional food components and their influence on immunological responses. Written in an accessible style, it addresses researchers, health professionals and students with different scientific backgrounds.