A randomized trial of two levels of iron supplementation and developmental outcome in low birth weight infants.

OBJECTIVES: To investigate the effect of increased iron intakes on hematologic status and cognition in low birth weight infants. STUDY DESIGN: We randomly assigned 58 infants to receive formula with 13.4 mg iron/L (normal iron) or 20.7 mg iron/L (high iron). At baseline, discharge, and at 3, 6, 9, and 12 months' corrected age, we assessed anthropometry; infections; red blood cell hemoglobin, catalase, glutathione peroxidase, red blood cell fragility (hydrogen peroxide test), and superoxide dismutase values; plasma malondialdehyde, ferritin, iron, transferrin, zinc and copper levels; and diet intake. Griffiths' Development Assessment was done at 3, 6, 9, and 12 months only. RESULTS: No statistical differences (P <.05) were noted for weight, catalase or malondialdehyde levels, red blood cell fragility, or Griffith's Development Assessment. Iron intakes were greater in the high iron group except at 12 months. Hemoglobin (high iron, 123 +/- 9; normal iron, 118 +/- 8) was not different at 3 months (P =.07). Plasma zinc levels (high iron, 70 +/- 14; normal iron, 89 +/- 27) and copper levels (high iron, 115 +/- 26; normal iron, 132 +/- 27; P =.06) at 12 months suggested inhibition of absorption by high iron formula. Glutathione peroxidase levels were higher in the high iron group. The total number of respiratory tract infections was greater in the high iron group (3.3 +/- 0.9) than in the normal iron group (2.5 +/- 0.9). CONCLUSION: In terms of cognitive outcome, there is no advantage associated with elevated iron intake for low birth weight infants.

Serum zinc, copper, and selenium concentrations in preterm infants receiving enteral nutrition or parental nutrition supplemented with zinc and copper.

Fifteen enterally fed preterm infants not receiving additional trace element supplements and 22 preterm infants receiving total or partial parenteral nutrition supplemented with zinc at 350 micrograms/kg/day and copper at 20 micrograms/kg/day were examined 1, 7, 14, 21, and 28 days after birth. Mean serum Zn concentrations in the parenteral group remained relatively constant and were significantly higher (P less than 0.01) at day 21 than the value for the enteral group. In contrast, a significant decline in mean serum Zn concentrations occurred between days 1 and 21 in the enteral group. The mean serum Cu concentrations in the parenteral group rose during the first week, and were significantly higher at days 14 and 21 than corresponding values in the enteral group. This trend did not result from copper supplementation alone but was also attributed to the presence of ceruloplasmin in blood transfusions. Mean serum Se concentrations did not change significantly, either between or within the two groups, except during the first week, at which time levels rose in the parenteral group. The addition of Zn, Cu, and probably of Se to parenteral infusates, allows the maintenance of appropriate serum values.