This book provides a review of the roles of specific nutrients in maintaining the immune response and host protection against infection. It also considers the influence of various factors, such as exercise and ageing, on the interaction between nutrition and immune function. The main emphasis is on humans, but comparative mammalian data are also presented.The contents include methods for studying nutrient-immune function interactions, the impact of undernutrition on immune function and infection, the influences of fatty acids, amino acids, antioxidant vitamins, and various minerals on immunity, immunological effects of changes throughout the life cycle, and public health policy implications.