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Immune response during disease and recovery in the elderly
- Bruno Lesourd
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- Journal:
- Proceedings of the Nutrition Society / Volume 58 / Issue 1 / February 1999
- Published online by Cambridge University Press:
- 08 December 2008, pp. 85-98
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The present article reviews immune ageing and its relationship with nutritional ageing, with a particular insight into the influences of disease on both ageing processes. Immune ageing can be described primarily as the progressive appearance of immune dysregulations, mainly acquired immunity (mature: immature, naive: memory T lymphocyte subset decreases) leading to gradual increases in T-helper 2: T-helper 1 cells. This change is due initially to decreased thymic function, and later to accumulative antigen pressure over the lifespan. In contrast, innate immunity (macrophage functions) is preserved during the ageing process and in the elderly this leads to macrophage–lymphocyte dysequilibrium, which is particularly critical during on-going disease. Indeed, any disease induces long-lasting acute-phase reactions in aged patients and leads to body nutritional reserve (mainly protein) losses. Episodes of disease in the aged patient progressively deplete body nutritional reserves and lead to protein–energy malnutrition, undernutrition-associated immunodeficiency, and finally cachexia. Undernutrition is a common symptom in the elderly; protein-energy malnutrition is found in more than 50 % of hospitalized elderly patients and in most elderly diseased subjects. In addition, micronutrient deficit or low levels are common in home-living self-sufficient apparently-healthy elderly subjects. All these nutritional deficits induce decreased immune responses, and micronutrient deficits are now thought to be partly responsible for the decreased immune responses (immune ageing?) observed in the apparently-healthy elderly. Indeed, several studies have shown that micronutrient supplements induce increased immune responses in the healthy elderly. The progression of infectious diseases depends on immune responses and on nutritional status before the onset of illness in aged subjects. In addition, recovery depends on the intensity of acute-phase responses in the undernourished elderly. In fact, chronic acute-phase responses, commonly associated with diseases in aged patients, lead to progressive lowering of metabolic responses in the undernourished elderly. This can be quantified by increased production of free radicals during treatment and these increases may explain the difficulty in successfully treating aged patients. Nutritive therapy in order to improve metabolic processes and also to maintain body reserves should be considered as a necessary adjuvant therapy in the treatment of elderly patients.
Nutritional factors and immunological ageing
- Bruno Lesourd
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- Journal:
- Proceedings of the Nutrition Society / Volume 65 / Issue 3 / August 2006
- Published online by Cambridge University Press:
- 07 March 2007, pp. 319-325
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Undernutrition profoundly affects immune responses, particularly at the extremities of life: in infants and in the elderly. The present review focuses on this interrelationship in the elderly. It describes three different stages of ageing: stage 1, healthy ageing, which is observed in very healthy elderly individuals who have no nutritional deficit; stage 2, common ageing, which is observed in most elderly individuals in whom various micronutrient deficits are found; stage 3, pathological ageing, which is observed in patients with protein–energy deficiency. Stage 1, primary immune ageing, is essentially characterized by changes in T-cell subsets but no change in T-cell function; T-cell function is reduced only in the very elderly (>90 years old). Stage 2, secondary immune ageing, is influenced by micronutrient deficits that may be corrected by providing nutritional supplements. Furthermore, immune responses may also be enhanced by supplementation of subjects who have no micronutrient deficits, indicating that the immune system of elderly individuals is highly susceptible to the influence of micronutrients. In stage 3, tertiary immune ageing, the immune responses are strongly related to the decreased nutritional status. In these patients decreased immune responses lead to long-lasting acute-phase responses, which induce greater use of nutritional reserves during disease and lead to increased frailty. As nutritional status has a marked effect on immune responses in elderly individuals, nutritional therapy should be given to elderly individuals who have nutrient deficits, and perhaps also to individuals who do not have nutrient deficits in order to promote healthy ageing and extend the lifespan.
Nutrition and immunity in the elderly
- Bruno Lesourd, Lynda Mazari
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- Journal:
- Proceedings of the Nutrition Society / Volume 58 / Issue 3 / August 1999
- Published online by Cambridge University Press:
- 28 February 2007, pp. 685-695
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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.
Markers to measure immunomodulation in human nutrition intervention studies
- Ruud Albers, Jean-Michel Antoine, Raphaëlle Bourdet-Sicard, Philip C. Calder, Michael Gleeson, Bruno Lesourd, Sonia Samartín, Ian R. Sanderson, Jan Van Loo, F. Willem Vas Dias, Bernhard Watzl
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- Journal:
- British Journal of Nutrition / Volume 94 / Issue 3 / September 2005
- Published online by Cambridge University Press:
- 08 March 2007, pp. 452-481
- Print publication:
- September 2005
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Normal functioning of the immune system is crucial to the health of man, and diet is one of the major exogenous factors modulating individual immunocompetence. Recently, nutrition research has focused on the role of foods or specific food components in enhancing immune system responsiveness to challenges and thereby improving health and reducing disease risks. Assessing diet-induced changes of immune function, however, requires a thorough methodological approach targeting a large spectrum of immune system parameters. Currently, no single marker is available to predict the outcome of a dietary intervention on the resistance to infection or to other immune system-related diseases. The present review summarises the immune function assays commonly used as markers in human intervention studies and evaluates their biological relevance (e.g. known correlation with clinically relevant endpoints), sensitivity (e.g. within- and between-subject variation), and practical feasibility. Based on these criteria markers were classified into three categories with high, medium or low suitability. Vaccine-specific serum antibody production, delayed-type hypersensitivity response, vaccine-specific or total secretory IgA in saliva and the response to attenuated pathogens, were classified as markers with high suitability. Markers with medium suitability include natural killer cell cytotoxicity, oxidative burst of phagocytes, lymphocyte proliferation and the cytokine pattern produced by activated immune cells. Since no single marker allows conclusions to be drawn about the modulation of the whole immune system, except for the clinical outcome of infection itself, combining markers with high and medium suitability is currently the best approach to measure immunomodulation in human nutrition intervention studies. It would be valuable to include several immune markers in addition to clinical outcome in future clinical trials in this area, as there is too little evidence that correlates markers with global health improvement.