Nutrition and immunity in the elderly

Abstract

Immune function declines with age, leading to increased infection and cancer rates in aged individuals. In fact, recent progress in the study of immune ageing has introduced the idea that rather than a general decline in the functions of the immune system with age, immune ageing is mainly characterized by a progressive appearance of immune dysregulation throughout life. Changes appear earlier in life for cell-mediated immunity than for humoral immunity. Thus, agerelated modifications in cell-mediated immunity, i.e. changes in naive : memory T-cells, mature : immature T-cells, T-helper 1 : T-helper 2 cells are more important in the elderly than changes in humoral immunity, i.e. CD5 : CD5+ cells or length of antibody responses. Such evolution of the immune system has been linked to declining thymus function and to accumulative antigenic influence over the lifespan. In contrast, innate immunity (macrophage functions) is preserved or even increased during the ageing process. This finding shows that the 'primitive' immune system is less affected by the ageing process than the sophisticated specific immune system. The present review focuses on innate and cell-mediated immune changes with ageing. It provides evidence that primary changes (intrinsic modifications in the immune system) and secondary changes (resulting from environmental influences during the lifespan) exert different influences on the immune system. Primary changes, occurring in healthy individuals, seem less important nowadays than they were considered to be previously. For example, interleukin 2 secretion in some very healthy aged individuals is comparable with that in younger adults. Primary immune changes may not explain the increased incidence and severity of infections observed in the elderly population. Secondary immunological changes are far more frequent and are certainly responsible for most of the immune modifications observed in the elderly population. Environmental factors leading to secondary immune dysfunctions include not only antigenic influence, which is a reflection of diseases experienced over the lifespan, but also many other factors such as drug intake, physical activity and diet; factors for which important changes occur in the elderly population. Nutritional factors play a major role in the immune responses of aged individuals and the present review shows that nutritional influences on immune responses are of great consequence in aged individuals, even in the very healthy elderly.

Zinc status and age-related changes in peripheral blood leukocyte subpopulations in healthy men and women aged 55–70 y: the ZENITH study

“…In has been suggested that enhanced innate immunity may occur with age as a countermeasure against declining CMI. In particular, numerous studies have reported increased numbers of NK cells (irrespective of the surface marker used to characterise them) with advancing age (for reviews, see Lesourd & Mazari, 1999;Mocchegiani & Malavolta, 2004). Preservation of NK cell cytotoxicity and numbers in middle age may be crucial in preventing the development of some age-related diseases and achieving successful ageing; it has been demonstrated that NK cell function is the only parameter in the healthy elderly to be negatively correlated with a severe history of infection or subsequent death owing to infection (Ogata et al, 1997).…”

“…The majority of studies examining zinc status and immune function have focused on infectious disease in childhood (Bahl et al, 1998;Black, 2003;Wieringa et al, 2004) and the elderly (Bogden et al, 1988;Prasad et al, 1993;Ravaglia et al, 2000;Bogden, 2004;Lesourd, 2004). There is a distinct lack of studies that have investigated the age-related changes in immune function in the late-middle-aged population (55-70 y), or indeed that have assessed zinc status of this age group.…”

Implementation of the EGFP‐K562 flow cytometric NK test: Determination of NK cytotoxic activity in healthy elderly volunteers before and after feeding

“…A number of reports (9,12,13,15,17-19,20 22,23,30) give highly variable results on NK cytotoxic activity ( Table 2). The role played by the neuroendocrine immune network and/or by nutritional factors in the maintenance of NK cell functions in ageing has also been widely discussed (20,(31)(32)(33).…”

“…Similarly, there is strong evidence that undernutrition induces immunodeficiency. Several reports (18,34) provide evidence that human immune ageing is strongly influenced by nutritional factors, mainly low nutritional diet in either macro-or micronutrients. Our data also show an increasing capacity of NK cells to kill target cells.…”

Effects of arginine supplementation on the humoral and innate immune response of older people

“…Although some experimental studies have suggested that the use of arginine as a supplement leads to clinical benefits in critically ill patients (Muhling et al, 2002;Lesourd, 2004), there is a lack of studies about the potential benefits of any nutrients supplementation after pneumococcal immunization of older persons, free-living in the community. Considering the individual variation in the immune response to pneumococcal vaccine and the reported benefits of arginine supplementation for immune function, this study intended to verify whether or not oral arginine supplementation affects the humoral response against the pneumococcal polysaccharide vaccine and some variables of the innate immune response in a group of persons aged 60 y and older, living in the community.…”