Nutrition and the immune response -- a review.

This compacted overview of the nutrition-immune response connection underscores the role of nutrition as a deterrent to infection. Malnutrition enhances the propensity to and heightens the intensity of infections by weaknening the various host defense mechanisms. Thus: 1. Deficiencies of vitamin A, niacin, riboflavin, folic acid, vitamin B12, pyridoxine, ascorbic acid, iron and protein disrupt the tissue barriers to infection. 2. Protein-calorie, folate, iron, pyridoxine and zinc deprivations markedly depress the cell-mediated immune system. 3. Deficiencies of protein, pyridoxine, folic acid, pantothenic acid, thiamine, biotin, riboflavin, niacin-tryptophan, vitamin A and ascorbic acid inhibit humoral antibody formation in mammalian systems. 4. Vitamin A lack prevents the formation of lacrimal, salivary and sweat gland lysozymes. 5. Complement, properdin, interferon and transferrin concentrations are reduced in those nutritional deficiencies that interfere with protein synthesis. 6. Protein-calorie, iron and folate deficiencies impair phagocytosis by interfering with phagocyte microbial killing power or with phagocyte production. 7. Protein, ascorbic acid and zinc deficiencies retard wound healing that prevents spread of infectious lesions.