Iron, zinc, copper and selenium status of breast‐fed infants and infants fed trace element fortified milk‐based infant formula

Abstract

Infants were fed cow's milk-based formulas containing 4 mg of iron/l from 1.5 to 6 months of age and their hematological status was compared to infants receiving the same formula but with 7 mg of iron/l and with breast-fed infants. One formula with 4 mg of iron/l contained iron as ferrous sulfate, in another, part of the iron was provided as bovine lactoferrin. We also studied the effect of selenium (10 micrograms/l) and copper (0.4 mg/l) supplementation on selenium and copper status. There were no significant differences in hematological indices among the groups at 6 months of age; all infants had satisfactory iron status. Serum transferrin receptor levels, a potential novel indicator of iron status, were highest in breast-fed infants, suggesting a cellular need for iron, and lowest in infants receiving formula with 7 mg of iron/l. Selenium status, as assessed by serum glutathione peroxidase activity, was similar at 6 months of age in breast-fed infants and infants fed formula fortified with selenium but lower in infants fed unfortified formula. The lowest levels of glutathione peroxidase activity were found in infants fed the highest concentration of iron (7 mg/l). Serum copper concentrations were similar in all groups, but the lowest levels were found in infants fed the highest concentration of iron. These results suggest that 4 mg of iron/l is adequate for infants up to 6 months of age and that higher levels may have some negative effects.