Nutrition and immunity in the elderly: modification of immune responses with nutritional treatments

Abstract

Nutrition has a strong influence on the immune system of the elderly. Aging induces dysregulation of the immune system, mainly as a result of changes in cell-mediated immunity. Aging is associated with changes to the equilibrium of peripheral T and B lymphocyte subsets, such as decreases in the ratios of mature to immature, naive to memory, T helper 1 subset (TH1) to TH2, and CD5- to CD5+ cells. As a consequence, cell-mediated immune responses are weaker and neither cell-mediated nor humoral responses are as well adapted to the antigen stimulus. Undernutrition, common in aged populations, also induces lower immune responses, particularly in cell-mediated immunity. Protein-energy malnutrition is associated with decreased lymphocyte proliferation, reduced cytokine release, and lower antibody response to vaccines. Micronutrient deficits, namely of zinc, selenium, and vitamin B-6, all of which are prevalent in aged populations, have the same influence on immune responses. Because aging and malnutrition exert cumulative influences on immune responses, many elderly people have poor cell-mediated immune responses and are therefore at a high risk of infection. Nutritional therapy may improve immune responses of elderly patients with protein-energy malnutrition. Supplementation with high pharmacologic doses of a single nutrient (zinc or vitamin E) may be useful for improving immune responses of self-sufficient elderly people living at home. Therefore, nutritional deficiency must be treated in the elderly to reduce infectious risk and possibly slow the aging process.

Malnutrition and associated factors among aged residents in all nursing homes in Helsinki

“…Thus, the studied, aged residents are representative of those old people who permanently live in nursing homes. It was already known from previous studies that malnutrition is a common problem among aged residents in institutional care facilities (Abbasi & Rudman, 1993;Lesourd, 1997;Saletti et al, 2000). However, large-scale studies performed with the validated MNA in nursing home populations are still scarce (Saletti et al, 2000;Van Nes et al, 2001).…”

“…Protein malnutrition is associated with falls, sarcopenia and hip fractures (Morley & Silver, 1995). Aging and malnutrition induces impairment in immune responses that exposes aged people to infections (Lesourd, 1997).…”

Zinc and immune function

“…It is well known that aging is often associated with a decreased immune function, particularly the cell mediated response and substantial vulnerability to respiratory tract infections, associated with greater morbidity and mortality (Lesourd, 1997). Changes associated with aging may be in part the result of zinc deficiency, which induces comparable impairment of immune response (Table 1).…”

Unintended weight loss in the elderly living at home: The aged in home care project (ADHOC)

“…These included improved health, decreased dependence, and reduced time required to recuperate from illness. On the other hand, undernutrition may lead to severe consequences, including reduced self-care, comorbidity (7), infections (8,9), hospitalisation, and longer stay after admission (10), in addition to increased mortality (11,12). Poulsen (4) stated that simple questions and clinical examinations at admission to hospital could identify relevant risk factors for undernutrition.…”