When does malnutrition become a risk?

Malnutrition has been defined as a deficiency of energy, protein or other types of nutrients, which produces alterations in body function, is associated with worse outcome from illness and is reversible by nutritional support [1]. Global malnutrition generally results from simple starvation or stress starvation and has to be distinguished from deficiency of one micronutrient or vitamin [2]. Starvation results from a pure deficit of all macroand micronutrients and occurs for instance in hunger strikers, persons with anorexia, or patients with intestinal diseases leading to malabsorption. Stress starvation, or cachexia, represents the accelerated loss of muscle mass in response to metabolic stress and generally affects patients with inflammatory or neoplastic diseases. Some authors report a third type of malnutrition, sarcopenia [3], which reflects loss of skeletal muscle in the elderly as well as in persons who repeatedly try to lose weight by dieting and in people with growth hormone deficiency, immobilization or arthritis. However, it is questionable whether cachexia and sarcopenia are totally different entities because they may share one or more common pathophysiologic causes including metabolic stress. Whatever the specific etiology is, global malnutrition results in decreased body cell mass (BCM) and fat-free mass (FFM) and leads to diminished body function. FFM can routinely be assessed by several methods, including measurements of skinfold thickness, arm circumference, bioelectrical impedance analysis (BIA) or dual energy X-ray absorptiometry (DXA). In many studies, parallel decreases in BCM and quality of life have been demonstrated [4–7] Lochs H, Thomas DR (eds): Home Care Enteral Feeding. Nestlé Nutrition Workshop Series Clinical & Performance Program, vol 10, pp 73–88, Nestec Ltd., Vevey/S. Karger AG, Basel, © 2005.