Basic Concepts of Immunology and Its Application to Clinical Nutrition

In recent years, evidence has accumulated on the effects of nutrients on metabolic processes. The role of specific nutrients in modulating immune function has received much attention because of the significant role of the immune system in a variety of disease states. The immune system depends on the complex interactions of its various parts. In response to an "antigen" or foreign substance that penetrates the external protective barriers of the human body, nonspecific (phagocytes, complement) defense mechanisms and antigen-specific factors are activated. The antigen-specific immune system relies on both humoral (antibodies and B cells) and cellular (T cells and lymphokines) defenses. Malnutrition causes a decline in all aspects of host defense. Correction of malnutrition in hospitalized patients and restoration of immunocompetence has become a goal of nutrition support practitioners today. The application of current research findings to patient care requires a basic understanding of immunology.