Nutrition and immune function in the geriatric population.

Aging in experimental animals and in man is associated with a significant defect of helper/inducer T-lymphocytes. This quantity deficiency is paralleled by a qualitative deficiency of T-lymphocyte number and function. Similar defects have been observed in protein calorie malnutrition and zinc deficiency, and there is evidence that both may exist in the aged ill and perhaps even in aged healthy individuals. Nutritional support improves the immune defect in aged ill patients and it may be of value in improving this deficiency, even when administered to aged healthy subjects.