It has been thought that providing iron in infant formula is less likely to have adverse effects as a relatively small percentage of the iron is absorbed. It was recently shown, however, that feeding infants formula fortified with iron at a level of 12.7 mg/l as compared to 2.3 mg/l from 6 to 12 months of age resulted in better cognitive development outcomes at 10 years of age when their hemoglobin levels were lower than 105 g/l at the start of the intervention, but poorer outcomes when they were higher than 128 g/l [11]. Again, the mechanism behind this observation is not known. Taken together, it is apparent that some caution about providing excess iron to infants with an adequate iron status is warranted.