It has been recognized for many years that states of nutrient deficiency are associated with an impaired immune response and with increased susceptibility to infectious disease. In turn, infection can affect the status of several nutrients, thus setting up a vicious circle of under nutrition, compromised immune function and infection. Thus, the focus of much of the research into nutrition, infection and immunity has been related to identifying the effects of nutrient deficiencies upon components of the immune response (often using animal models) and, importantly, upon attempts to reduce the occurrence and severity of infectious diseases (often in human settings). Although it is often considered that the problems.
