[Pathophysiology of catabolism in undernurished elderly patients].

Malnutrition is a common finding amongst our elders. The causes of malnutrition are multifactorial and although they have been extensively studied, they are not entirely understood. Both physiological and pathological processes of aging put this population at a higher risk of being undernourished. These may be related to social, financial, psychological and/or physiological changes directly or indirectly associated to growing old. Age associated changes increase the risk of malnutrition in older individuals. These alterations range from problems in taste and smell perception, which were previously thought to be the main cause of anorexia in this population, to alterations in either the concentration or efficacy of the previously mentioned feeding modulators. Increased intestinal malabsorption together with an altered pancreatic exocrine response to different diets, further contributing to subclinical malabsorption in the elderly population aged and may account in part for the malnutrition observed in this group. Although not directly caused by the aging process, several conditions such as anorexia nervosa, cancer, infectious conditions, and inflammatory processes are associated with decreased food intake and weight loss. These conditions present with elevated levels of immunoregulatory substances known as cytokines. Each of these cytokines has multiple effects and play a leading role in the pathophysiology and maintainance of malnutrition in these situations.