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Iron supplementation given to nonanemic infants: neurocognitive functioning at 16 years
Patricia L East1, Brie Reid2, Estela Blanco1,3
1Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA.
Insights
Iron supplementation in nonanemic infants may negatively impact neurocognitive development, leading to poorer skills in visual-motor integration and reasoning. This highlights potential risks of high iron intake during early brain development.
Area of Science:
- Neuroscience
- Developmental Pediatrics
- Nutritional Science
Background:
- Early brain development is a critical period sensitive to nutrient availability.
- Concerns exist regarding the potential risks of high iron uptake in nonanemic infants during this sensitive developmental window.
- Iron supplementation is common, but its long-term effects on neurocognitive outcomes in healthy infants require further investigation.
Purpose of the Study:
- To examine the long-term neurocognitive functioning of individuals who received iron supplementation as nonanemic infants.
- To assess the relationship between infant iron intake and adolescent neurocognitive performance.
- To evaluate potential risks associated with iron supplementation in early brain development.
Main Methods:
- A randomized controlled trial involving 562 Chilean adolescents (mean age 16.2 years) who participated in an infant iron supplementation study.
- Participants were assigned to either an iron-fortified formula/supplement group or a no-added iron control group between 6 and 12 months of age.
- Neurocognitive functioning was assessed in adolescence.
Main Results:
- Adolescents who received iron supplementation in infancy demonstrated poorer visual-motor integration, quantitative reasoning, and increased errors on neurocognitive tasks compared to controls.
- Higher intake of iron-fortified formula in infancy correlated with lower arithmetic achievement.
- In subgroups stratified by hemoglobin levels, iron supplementation was associated with poorer performance in specific cognitive domains.
Conclusions:
- High iron supplementation in nonanemic infants may pose risks to neurocognitive development.
- The balance between the physiological need for iron and potential risks of over-supplementation in early infancy warrants careful consideration.
- Findings suggest a need to re-evaluate current iron supplementation guidelines for nonanemic infants.
Objective:
There is concern that high iron uptake during the critical period of early brain development carries potential risks, especially for nonanemic infants. This study examined the neurocognitive functioning of 16-year-olds who were nonanemic as infants and received iron supplementation.
Methods:
We studied 562 Chilean adolescents (M 16.2 years; 52.7% female) who participated in a randomized controlled iron supplementation trial in infancy. Between 6 and 12 months, 346 consumed an iron-fortified formula (12.7 Fe mg/L) or, if primarily breastfed, liquid vitamins with 15 mg elemental iron as ferrous sulfate, and 216 consumed unmodified cow milk without iron or liquid vitamins without iron if primarily breastfed.
Results:
Compared to adolescents in the no-added iron condition in infancy, those in the iron-supplemented condition had poorer visual-motor integration, quantitative reasoning skills, and incurred more errors on neurocognitive tasks. Consuming larger amounts of iron-fortified formula in infancy was associated with lower arithmetic achievement. Of adolescents who had high hemoglobin at 6 months (Hb ≥ 125 g/L), those in the iron supplemented condition had poorer performance on arithmetic, quantitative reasoning, and response inhibition tests than those in the no-added iron condition. Of adolescents who had marginally low 6-month hemoglobin (Hb > 100 and < 110 g/L), those who received no-added iron incurred more errors on a visual searching task than those in the iron-supplemented condition.
Conclusion:
The physiologic need for iron during the period of rapid and critical brain development in young infants should be considered vis-à-vis the risks associated with supplementing nonanemic infants with high levels of iron.Clinical Trials number: NCT01166451.
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