AGEING: BIOLOGY AND NUTRITION: Edited by Tommy Cederholm and John E. Morley
Biology and nutrition related to ageing is becoming increasingly important. Both affluent societies and developing countries face dramatic demographic shifts that impose new medical and societal challenges. Poverty and famines mainly striking younger populations are still abundant in areas of the world, but progress is being made and more and more focus of health planning is directed towards the older population. In particular, there is an increased recognition that anorexia and undernutrition are common in older persons [1,2]. Cachexia is an important problem for many older persons in the last few years of their life . This year's section of Ageing: Biology and Nutrition will deal with issues that increase the understanding of the catabolic processes that occur with ageing and that explains much of the age-related deterioration, hampering quality of life in senescence. Hopefully, such increased understanding will eventually contribute to compression of morbidity and more years of active and healthy life added to the life of old people.
To summarize the contributions to this year's section we start with a contribution from Maggio et al. (pp. 3–13). Maggio provides an excellent overview of the emerging evidence that anabolic steroids either alone or in combination with protein may be a reasonable treatment for sarcopenia. Due to potential side-effects, much knowledge is still needed to understand who to target, which doses to provide, how to combine and when to abstain from treatment.
This is followed by Francheschi's study that discusses the role of ageing itself as an underlying mechanism for inflammatory activity; a condition that is called ‘inflammaging’ by the authors. The role of cellular senescence, metabolic disturbances and gut microbiota is discussed and a new EU-funded project to illuminate potential protective roles of nutrition for inflammaging is described.
Next, Manini et al. (pp. 21–26) introduce an interesting neurological perspective on the development of sarcopenia. Sarcopenia, that is, the gradual loss of muscle mass and function with ageing, is mainly considered a phenomenon restricted to alterations of the muscle alone. Here we are provided with arguments that the neurological ageing as well contribute to the sarcopenic phenotype. Neuronal atrophy, blurred signal transmission, altered myelinization, reduced motor cortex plasticity are some of the conditions discussed, leaving the conclusion that not only intramuscular targets need to be focused but also novel approaches to sustain nervous system functions in order to balance sarcopenia. Sarcopenia has recently been reviewed in detail in this journal [4,5] and several new definitions have been published to take into account the need to recognize the need to include function on the definition [6–8]. Resistance exercise has been demonstrated to markedly improve outcomes in frail sarcopenic persons with muscle loss .
Recent findings related to the understanding of anorexia of ageing are reported by Morley (pp. 27–32). Anorexia of ageing precedes weight loss and can easily be recognized by the Simplified Nutritional Assessment Questionnaire (SNAQ). New data on the role of anorectic hormones like cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1), fat-cell derived leptin and cytokines, as well as on orexigenic agents like ghrelin are discussed. Psychosocial factors are stressed. Depression is highlighted as the most common cause for anorexia in old adults. So far pharmacological approaches, for example, orexigenic drugs have not proven beneficial.
The physiology of the ageing gut is the theme for the study from Rayner and Horowitz (pp. 33–38). Many gut functions appear to be well preserved during ageing, especially motor tasks, whereas sensory function deficits are more common. Still, experimental progeria models show reduced myosin expression in aged gut smooth muscle. Dysphagia, gastrooesophageal reflux, constipation and fecal incontinence are particularly prevalent clinical gut manifestations of ageing. Interestingly, mechanisms behind postprandial hypotension (a risk factor for falls) in old patients are discussed.
Skin ulcers are common in older adults and have strong implications for nutrition, which become evident from the study of Little (pp. 39–49). Malnutrition is one important underlying factor for skin ulcers, and skin ulcers trigger catabolic activities, thus, fuelling a vicious cycle. The potential roles of energy supply and intake of protein, vitamins and trace elements are discussed. The evidence base for nutritional treatment of skin ulcers is fairly weak, but still ‘there seem to be evidence for protein supplementation to promote wound healing’. Newer approaches like supplementation with arginine or glutamine still need further research.
The final study of this year's Ageing: Biology and Nutrition section of COCNMC deals with polypharmacy and malnutrition. It defines polypharmacy and describes its consequences for the nutritional status in the old patient.
Nutrition is fundamental for health as well as for physical and cognitive functions at old age. Everyday exposure during a lifetime for various nutrients eventually has beneficial or detrimental effects emerging at the end of life. This trajectory could be difficult to affect by late-life changes, although it is never too late. However, as illuminated by the studies of this section many age-related physical phenomena are sensitive to nutritional influences, leaving a good part of the quality of life of the senescent subject to the individual's own domain of decision.
Conflicts of interest
J.M. performs research projects with Nutricia, Purina and Sanofi.
T.C. performs research projects in collaboration with Nutricia and Nestle.
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