The use of bioelectrical impedance analysis for monitoring body composition changes during nutritional support.

Body composition was measured with bioelectric impedance analysis (BIA) in 30 patients with protein malnutrition following biliopancreatic diversion. Determinations were carried out prior to, during, and at the completion of intravenous nutritional support when the nutritional parameters had completely reverted to normal. Before treatment, body weight (BW), lean body mass (LBM), and body fat (BF) values were similar to those of controls, whereas the total body sodium/total body potassium (TBNa/TBK) and extracellular mass/body cell mass (ECM/BCM) ratios were considerably higher. During the support, no changes in BW, LBM, and BF were demonstrated, although a sharp decrease of TBNa/TBK and ECM/BCM was observed, thus demonstrating improved LBM composition. At the end of parenteral feeding, the BW, LBM, and BF values were similar to those observed before the support, while a further decrease in TBNa/TBK and ECM/BCM demonstrated a recovery towards normal of body composition. The full correspondence between clinical and BIA findings therefore suggests that this method may be valuable for monitoring body composition changes during nutritional support.