Micronutrient supplementation and immune function in the elderly.

Immunologic function, particularly cell-mediated immunity, declines with age, contributing to the increased incidence of infectious diseases in the elderly. Nutrition may play a pivotal role in maintaining immune competence in older adults. Most studies to date have focused on micronutrient deficiencies and supplementation, sometimes using "mega-dose" formulations. Multivitamin/mineral supplements or specific micronutrients such as zinc and vitamin E may be of value; however, data suggest there is likely a therapeutic range for many micronutrients, and oversupplementation may be harmful. Specific alterations of dietary lipids may also be useful for modulating immune responses in the elderly. This review summarizes the prevalence of vitamin and mineral deficiencies in older adults and highlights the outcomes of trials of micronutrient supplementation to augment immune function in the elderly.