Anorexia of aging.

Anorexia of aging is a physiologic decrease in food intake, which gradually leads to weight loss accompanied by age-related changes in body composition. Animal experiments have revealed that advanced age is associated with altered regulation of food intake and energy homeostasis: suppression of orexigenic mechanisms mediated by neuropeptide Y, orexins, and ghrelin, and by increased activity of the major anorexigenic neuropeptide, α-MSH. In the elderly, a reduced sense of smell and taste may contribute to the loss of appetite, and in old humans, increased serum cholecystokinin concentration may delay gastric emptying resulting in a prolonged feeling of satiety. Although leptin and insulin play a major role in the control of energy homeostasis, their role in the loss of body weight in healthy elderly persons remains to be established. In some of the elderly, loss of body mass may result in malnutrition or even cachexia. Anorexia of aging plays some role in sarcopenia, involuntary loss of muscle mass and strength; however, there are intrinsic age-related changes in skeletal muscle, which underlie this health-endangering condition. Currently, there is no efficient pharmacological treatment for the anorexia of aging; however, it may be partially prevented by improved processing and presenting of food, physical training, and an appropriate social environment.