ARS | Publication request: The role of nutrition in enhancing immunity in aging

Submitted to: Aging and Disease
Publication Type: Review Article
Publication Acceptance Date: September 25, 2011
Publication Date: February 1, 2012
Citation: Pae, M., Meydani, S., Wu, D. 2012. The role of nutrition in enhancing immunity in aging. Aging and Disease. 3:91-129.

Technical Abstract: Aging is associated with declined immunity, particularly T cell-mediated activity, which contributes to increased morbidity and mortality from infectious disease and cancer in the elderly. Studies have shown that nutritional intervention may be a promising approach to reversing impaired immune functions and diminished resistance to infection with aging. However, controversy exists concerning every nutritional regimen experimented on to date. In this article we will review the progress of research in this field with by focusing on a few representative nutrition factors for which information in the literature is relatively abundant. While vitamin E deficiency is rare, its increased intake at above recommended levels can enhance T cell function in aged animals and humans. This effect is believed to contribute toward increased resistance to influenza infection in animals and reduced incidence of upper respiratory infection in the elderly. Zinc deficiency, common in the elderly, is linked to the impaired immune function and increased risk for acquiring infection, which can be rectified by zinc supplementation. However, higher than recommended upper limits of zinc may adversely affect immune function. Probiotics are increasingly being recognized as an effective immune-modulating nutrition factor. However, their effect is strain specific and requires an adequate supplementation period. A synergestic effect is also observed when more than one strain is used. Fish oil or n-3 PUFA have shown beneficial effects in inflammatory and autoimmune disorders as well as several age-related diseases. However, animal and human studies have shown a suppressive effect of fish oils on T cell mediated function, raising concern regarding their impact on resistance to infection. Caloric restriction (CR) is shown to delay immunosenescence in animals, and this effect in humans needs to be verified. Timing for CR initiation may be important to determine whether CR is effective and even, beneficial at all. Recent studies have suggested that CR, while effective in improving the immune response of unchallenged animals, might compromise the host's defense against pathogenic infection resulting in higher morbidity and mortality. The studies published thus far describe a critical role for nutrition in maintenance of the immune response in the aged, but they also indicate the need for a more in-depth and wholistic approach to determining the optimal nutritional strategies that would extend the span of a healthy functioning immune system in the aged and their resistance to infection and other immune-related diseases.