Evaluation of nutritional status.

The assessment of nutritional status has become very popular, especially for patients undergoing stress (surgery) or potential parenteral nutrition. Evaluation of cancer patients is essentially the same as for other patients. Body fat reserves are approximated by subcutaneous skinfold measurements. Somatic protein (skeletal muscle) mass is decreased in marasmus (protein-calorie malnutrition) and is evaluated by anthropometric determinations, based upon age and sex or both. Instead of using relatively inadequate standards such as the 1959 Metropolitan Life Insurance tables for ideal weight, it is advocated to use the population percentiles derived from the Health and Nutritional Examination Survey (HANES) published in 1979. The visceral protein mass is decreased in kwashiorkor and is approximated by study of the liver transport proteins. A mixed-type of protein-calorie malnutrition may exist, e.g., cancer cachexia, with marked decrease of immunocompetence. A prognostic nutritional index, based on biologic measurements rather than true nutritional assessment, can predict the probability of complications and survival in severely ill patients. All such studies should be used to substantiate good clinical judgement, based on adequate history and physical examination with emphasis on the nutritional aspects.