ABSTRACT
Deficiency of iron is the most common nutritional problem worldwide, even in industrialized countries. This chapter describes the effects of nutrition on the immune system. There are two principal divisions of immunity: innate and adaptive. The innate or antigen-nonspecific processes include intact physical barriers of skin and mucous membranes, the complement system that includes both classical and alternate pathways of activation, phagocytes, lysozymes, mucus, and ciliary movement. Although antibodies and cell-mediated immune responses act in concert, each is somewhat more important for different types of microorganisms. Interactions of nutrition and immunity have several practical applications. Human malnutrition is usually a complex syndrome of multiple nutrient deficiencies. However, observations in laboratory animals deprived of one dietary element and findings in rare patients with a single nutrient deficiency have confirmed the crucial role of several vitamins and trace elements in immunocompetence.
