The effect of age on the caloric requirement of malnourished individuals

The effect of age on the response to total parenteral nutrition (TPN) was evaluated in 325 patients by measuring body composition by multiple-isotope dilution at the onset and at 2-wk intervals during the course of TPN. On the basis of their initial body composition, patients were divided into two groups: normally nourished and malnourished. TPN did not alter the body composition of the normally nourished patients. In the malnourished patients, a statistically significant correlation existed between the daily change in the dependent variable body cell mass (BCM) and the independent variables caloric intake, nutritional state, and age. With advancing age, more calories are required to maintain the BCM of malnourished patients. With a similar nutritional intake, a depleted BCM is restored more slowly in older patients. Age is a significant independent variable affecting the response to nutritional support.