Flux of amino acids across the leg was measured in malnourished cancer patients and three control groups: (a) malnourished patients without cancer; (b) well-nourished but acutely ill patients; and (c) well-nourished controls hospitalized for minor elective surgery. All patients were examined after an overnight fast, and some patients were reexamined 2 weeks later during enteral nutrition by gastric infusion of a formula diet.
The efflux of amino acids did not differ qualitatively or quantitatively between malnourished cancer patients and malnourished patients without cancer. Well-nourished patients with acute illness had the greatest release of amino acids after an overnight fast. The leg efflux of amino acids did not correlate with plasma insulin levels in any of the patient groups, either in the fasting or in the fed state. Enteral nutrition decreased the efflux of amino acids from the leg in malnourished patients without cancer, but not in the malnourished cancer group. Enteral nutrition resulted in an increased peripheral uptake of energy precursors as glucose, free fatty acids, and the branched-chain amino acids. This was concomitant with increase in plasma level of triiodothyronine in malnourished patients without cancer.
This study demonstrates that malnourished cancer patients do not differ from malnourished patients without cancer or from well-nourished patients after an overnight fast with respect to amino acid efflux from peripheral tissues, and thus shows normal adaptation for protein conservation. The results also suggest that conventional nasogastric tube-feeding was not sufficient alone to support normal replenishment of peripheral tissue in malnourished patients with and without cancer.
This work was supported by grants from the Swedish Cancer Society (Project 93), the Swedish Medical Research Council (Project 536), the Assar Gabrielsson Foundation, the Serena Ehrenstrom Foundation, the Swedish Medical Society, and the Gothenburg Medical Society.