Iron is a vital mineral requiring a delicate balance in the body. While too little iron can cause developmental issue in infants, too much can also have adverse effects. Many foods for infants and children are fortified with iron because many children in earlier decades were deficient. But has all this fortification lead to kids getting too much iron? A new study found that in the case of infant formula, the answer may be yes.
Published online prior to print in the journal Archives of Pediatric and Adolescent Medicine, the long term study examined low-iron infant formula vs. iron fortified formula. The findings raised questions about the optimal amount of iron in infant formula, as researchers discovered that high hemoglobin levels in infants who received iron fortified formula had more long term developmental problems.
Iron deficiency affects about 25% of babies worldwide, with some having iron deficiency anemia. Iron deficiency anemia causes problems with hemoglobin production, the compound red blood cells use to transport oxygen throughout the body. Iron needs are higher during infancy and adolescence, and while children can be iron deficient prior to developing anemia, in infancy this deficiency can result in delayed infant motor or mental function.
In previous years, a significant number of infants and children were iron deficient; hence the reason iron fortification in infant formula is now commonplace but little research has been done in recent years to assess the long-term outcomes of iron fortification. The study provided a 10 year follow up on 835 healthy, full-term infants living in Santiago, Chile. The babies were randomly assigned to either iron fortified formula or non-fortified. At the 10 year mark, researchers measured 473 children for IQ, mathematic achievement, spatial memory, visual-motor integration, motor skills, and visual perception.
The iron enriched formula group scored lower on every assessment when compared with the low iron group; and less than 10% of the low iron group met the criteria for iron deficiency. Despite the difference in iron consumption, researchers found no difference in iron status between the groups and only one child had iron deficiency anemia. Researchers also found that babies with the highest hemoglobin level (and indicator of iron status) at 6 months of age, scored poorer at the 10 year evaluation if they had received iron fortified formula, while those with the lowest 6 month hemoglobin scored highest at 10 years. The authors conclude that the study results should be approached with caution, as this is the only evidence of negative outcomes from iron fortification, noting that further research is needed.