Nestle Supplement 2

NUTRITION AND THE OLDER PERSON Cachexia. Severe wasting of both fat and fat-free mass is termed cachexia. Although there is no widely accepted definition, cachexia is best viewed as the cytokine-associated wasting of protein and energy stores due to the effects of disease.39 Systemic inflammation mediated through cell injury or activation of the immune system triggers an acute inflammatory response. Persons with cachexia lose roughly equal amounts of fat and fat-free mass while maintaining extracellular water and intracellular potassium. The loss of fat-free mass is mainly from the skeletal muscle. Specific disease states are frequently associated with cachexia (Table 3). Persons with cachexia due to cancer may deplete up to 80% of their muscle mass.40 More than 80% of persons with upper gastrointestinal cancer have cachexia at diagnosis, and more than 60% of lung cancer patients develop cachexia. HIV/AIDS,41 rheumatoid arthritis,42 chronic renal insufficiency, and chronic uremia43 have been associated with cachexia. Cytokines have a direct negative effect on muscle mass, and increased concentrations of inflammatory markers have been associated with a reduced lean mass.44–46 This direct effect also has been associated with a decline in muscle strength in older adults. A combination of elevated tumor necrosis factor and interleukin-6 was found in 31% of white men and 29% of black men and in 24% of white women and 22% of black women. For each standard deviation increase in tumor necrosis factor, a 1.2 kg–1.3 kg decrease in grip strength was observed after adjusting for age, clinic site, health status, medications, physical activity, smoking, height, and body fat. For each standard deviation of interleukin-6, a 1.1 kg–2.4 kg decrease in grip strength was observed.44 In women followed for 3 years, the baseline level of interleukin-6 predicted walking limitations and knee strength and diminished activities of daily living.47 In a sample of older persons with a mean age 71 years and no mobility or activities of daily living deficit at baseline, levels of interleukin-6 predicted mortality at 4 years.48 Cytokine-mediated cachexia is almost always associated with anorexia. Cytokines directly result in feeding suppression and lower intake of nutrients. Interleukin-1 beta and tumor necrosis factor act on the glucose-sensitive neurons in the ventromedial hypothalamic nucleus (a “satiety” site) and the lateral hypothalamic area (a “hunger” site).49 The data suggest that cytokine levels are commonly associated with disease conditions characterized by cachexia and may play a role in mortality, weight loss, and appetite suppression. In contrast to starvation, cachexia is remarkably resistant to hypercaloric feeding.37 TABLE 3. Conditions associated with cachexia Infections, eg, tuberculosis, AIDS Cancer Rheumatoid arthritis Congestive cardiomyopathy End-stage renal disease Chronic obstructive pulmonary disease Cystic fibrosis Crohn’s disease Alcoholic liver disease Elderly persons without obvious cause SUMMARY A therapeutic approach to the loss of skeletal muscle mass and strength in older persons depends on correct classification. The term sarcopenia should be reserved for age-related decline in muscle mass not attributable to the presence of proinflammatory cytokines. Cachexia may be a better term for a decline in muscle mass associated with known inflammatory disease states.While starvation due to protein energy undernutrition is widely regarded as the primary cause of loss of fat and fat-free mass in older persons, a failure to improve with nutritional replacement should trigger a consideration of other causes. Sarcopenia is mediated by a number of factors, including an age-related decline in hormonal status, degeneration of muscle innervation, genetic factors, activity levels, or coexisting disability. Cachexia defines a distinct clinical syndrome where the activation of proinflammatory cytokines has a direct effect on muscle metabolism and anorexia. The anorexia resulting from the effect of proinflammatory cytokines can initiate a vicious feedback loop leading to starvation. Starvation resulting from an inability to eat due to mechanical problems or a hypermetabolic state can directly lead to cachexia. Distinguishing starvation, sarcopenia, and cachexia can be difficult,since there can be an overlap between nutrient intake,hormonal deficiency, and disease activation.39 The importance of defining the distinction lies in developing a therapeutic approach to skeletal muscle loss and muscle strength in older persons. In all persons, the first consideration should be an evaluation of nutritional intake. A helpful instrument is the Simplified Nutritional Appetite Questionnaire (SNAQ). Based on the assessment of appetite, this instrument accurately predicts weight gain in the ensuing 6 months.50 Deficits in intake should be corrected whenever possible. However, the failure of appetite associated with cachexia may limit the success of the nutritional interventions. I DECEMBER 2007 • 5

Table of Contents Feed for the Digital Edition of Nestle Supplement 2

Nestle Supplement Table of Contents Introduction to Weight Loss in Older Persons Diagnosis and Management of Oropharyngeal Dysphagia in the Elderly The Danger of Weight Loss in the Elderly Nutrients and Frailty

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