Enhanced mobilization of iron from body stores in malnourished patients during intravenous nutritional support

Abnormal iron metabolism, characterized by low serum iron concentration and diminished saturation of iron-binding capacity, is known to occur in patients with malignant or inflammatory diseases. In this study, serum iron concentration and iron-binding capacity were measured in 21 patients with malignant disease, trauma or inflammatory illness before and during intravenous nutritional support without iron supplementation. Prior to nutritional support, the serum iron value averaged 26.0 +/- 3.5 micrograms per deciliter and the iron-binding capacity, 160.0 +/- 14.0 micrograms per deciliter. After ten to 21 days of parenteral nutrition, the serum iron-binding value serum iron concentration rose to an average of 68 +/- 9 micrograms per deciliter and the iron-binding capacity to 200 +/- 15 micrograms per deciliter, and increased reticulocytosis was observed. The rise in serum iron value reflected a shift of iron from body stores to plasma, since the saturation of iron-binding capacity increased from 18.0 +/- 3.5 to 36.0 +/- 4.0 per cent. Fever, granulocytosis, malignant disease, pulmonary infiltrates or open wounds persisted in all patients throughout the observation, ruling out resolution of a chronic process as the cause for rising serum iron levels. Changes in serum ceruloplasmin and ascorbate values also could not account for the rise. We propose the provision of adequate nutritional substrates to establish an anabolic state during total parenteral nutrition is associated with improved mobilization of iron from body stores.