Nutrient regulation of the immune response

Abstract

Summary There is a bidirectional interaction between nutrition, infection, and immunity: undernutrition decreases immune defenses, making an individual more susceptible to infection, but the immune response to an infection can itself impair nutritional status and alter body composition. Practically all forms of immunity are affected by protein-energy malnutrition, but nonspecific defenses and cell-mediated immunity are more severely affected than humoral (antibody) responses. Micronutrients are required for an efficient immune response, and deficiencies in one or more micronutrients diminish immune function. Essential fatty acids play a role in the regulation of immune responses, since they provide precursors for the synthesis of lipid mediators. Deficiencies in essential amino acids impair immune function, but some nonessential amino acids (e.g., arginine and glutamine) may become conditionally essential in stressful situations. Probiotic bacteria enhance immune function in laboratory animals and may do so in humans. Prebiotics may also have these effects. Breast milk has a composition that promotes the development of the neonatal immune response and protects against infectious diseases.