Iron requirements during the first 6 months of life in term infants

Perm infants fed formula which has not been fortified with iron frequently develop iron deficiency anaemia by 4-6 mo of age. The appropriate level of iron supplementation is however still under discussion. In Europe, formulas generally contain 7 mg of iron/L (1 mg/100 kCal), while a more generous level of 12 mg/L ( 1.8 mg/100 kCal) is used in the U.S. Both these levels of iron fortification prevent iron deficiency and anaemia during the first 6 months of life. Breast milk, on the other hand, only contains 0.2-0.4 mg of iron/L and iron deficiency is rarely seen in term infants at 6 mo of age. We have previously shown that at 6 mo of age there were no differences in hematological indices or iron status in term infants fed a formula containing 4 mg iron/L compared to infants fed a formula containing 7 mg/L, or breast-fed infants. We now report on a study in which healthy, term infants at 4 ±2 wks of age were randomized to 1 of 4 different cow's milk based infant formulas containing target levels of 4 or 2 mg iron as FeSO4, or 2 mg as bovine lactoferrin-bound iron per litre, One group (2 mg FeSO4) was also supplemented with nucleotides to a level typical of human milk. For comparison one group of infants were breast-fed to 6 mo of age. Anthropometric measurements were taken monthly and a venous blood sample at the start of the study and at 4 and 6 mo of age. There were no differences with respect to anthropometric measurements at any lime point, nor were there significant differences between the groups with respect to haematological parameters or iron status, including s-transferrin receptor levels, at 4 or 6 mo of age. At 6 mo of age, only 3 out of 60 infants had s-ferritin <12 jig/L. None of them had anaemia (Hb <105 g/L), two had low iron saturation and one. belonging to the 2 mg group, also had elevated T1BC and was most likely iron deficient. Based on this study 2 mg of iron/L appear adéquate lor term infants up to 6 mo of age.