Babies who don't have anemia and who receive iron fortified infant formula have poorer long-term developmental outcomes, a new study has revealed.
The finding is an outcome of the 10-year follow-up study, conducted in Santiago, Chile, examining iron-fortified vs. low-iron infant formula.
It raises questions about the optimal amount of iron in infant formula
"The high prevalence of iron deficiency in infancy has led to routine iron fortification of infant formula and foods in many countries," said lead study author Betsy Lozoff, M.D., a behavioural paediatrician at the University of Michigan Health System and research professor at the University of Michigan Centre for Human Growth and Development.
"These interventions help reduce iron-deficiency anaemia and iron deficiency without anaemia. However, the optimal amount of iron in such products, especially infant formula, is debated," she stated.
The study found that compared to the low-iron group children, the iron-fortified group scored lower on every 10-year outcome measured.
Of the seven tests administered at the 10-year follow-up, two (spatial memory and VMI) showed statistically significant lower scores in the iron-fortified group compared to the low-iron group, and four (IQ, visual perception, motor coordination and arithmetic achievement) showed suggestive trends that did not reach statistical significance.
The researchers also found that children with the highest haemoglobin levels at 6 months of age had lower 10-year scores if they had received the iron-fortified formula, but those with the lowest 6-month haemoglobin levels had higher scores.
"In conclusion, this study indicates poorer long-term developmental outcome in infants with high haemoglobin concentrations who received formula fortified with iron at levels currently used in the United States," the researchers said.
The study has been published in the Archives of Pediatrics and Adolescent Medicine.