Selenium supplementation in low-birthweight premature infants: relationship to trace metals and antioxidant enzymes.

We attempted to study the effect of selenium supplementation upon trace metal metabolism in low-birthweight infants less than 1000 g birthweight. Serum levels of the trace metals copper, zinc, and selenium; and white blood cell glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities were measured in conjunction with the trace metals when parenteral nutrition (TPN) was begun (sample A), at the initiation of enteral nutrition (sample B), and when TPN was discontinued (sample C). Two randomly selected groups of infants were evaluated: group S received selenium supplementation (1.34 micrograms/kg per d) in their parenteral nutrition solutions; group C was a control which did not receive selenium supplementation. Selenium levels declined to equally low levels in both groups by sample C, but were significantly higher in group S at sample B. GSH-Px activities demonstrated a significant increase at sample B in group S and then tended to decrease. In group C, GSH-Px tended to increase, then decreased significantly by sample C. Both groups received 20 micrograms/kg per d of copper in TPN, however, serum copper declined significantly at sample B in group S whereas there were no significant changes in group C. There were no significant changes in zinc and SOD levels. There were no significant differences between groups in clinical characteristics or outcome. This study suggests that a dose of supplemental selenium of 1.34 micrograms/kg per d in TPN is inadequate for low-birthweight premature infants. Selenium supplementation may also affect copper metabolism.