Lack of correlation between indices of nutritional status and immunologic function in elderly humans.

We studied 230 independently living healthy elderly men and women to examine the hypothesis that subclinical nutritional deficiencies contributed to depressed immune function seen in the elderly. Immunologic function was assessed with delayed type hypersensitivity skin testing to four antigens, in vitro lymphocyte culture with phytohemagglutinin, lymphocyte count, and presence of serum autoantibodies and circulating immune complexes. Nutritional status was assessed by 3-day diet records and also biochemical analyses of blood for vitamins A, B12, C, D, E, riboflavin, folic acid, and the minerals iron, copper, and zinc. Using a variety of analyses we found no association between malnutrition and depressed immunologic function in this population. We conclude that subtle nutritional deficiency is not a noticeable contributor to the immunodeficiency of aging, and that previously reported beneficial effects of "megadose" nutritional supplements on the immune response of elderly individuals probably represent a pharmacologic effect rather than the correction of nutritional deficiencies.