Food and Behaviour Research

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Effects of iron supplementation of low birth weight infants on cognition and behavior at 7 years

Berglund SK, Chmielewska A, Lindberg J, Westrup B, Hägglöf B, Norman M, Domellöf M (2017) Pediatr Res.  2017 Sep.  doi: 10.1038/pr.2017.235. [Epub ahead of print] 

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Low birth weight infants (LBW) are at increased risk of iron deficiency which has been associated with impaired neurodevelopment. We hypothesized that iron supplementation of LBW infants improve cognitive scores and reduce behavioral problems until school age.


We randomized 285 marginally LBW (2000-2500 g) infants to receive 0, 1, or 2 mg/kg/day of iron supplements from six weeks to six months of age. At 7 years of age, 205 participants were assessed regarding cognition using Wechsler Intelligence Scale for Children (WISC-IV) and behavior using the parental questionnaires Child Behavior Checklist (CBCL) and Five to Fifteen (FTF).


There were no significant differences between the intervention groups in WISC-IV or FTF. However, the CBCL scores for externalizing problems were significantly different, in favor of supplemented children (P=0.045). When combining the supplemented groups they had significantly lower scores for externalizing behavior compared to placebo (median [IQR]: 44 [34;51] vs. 48.5 [41;56] P=0.013), and their risk ratio (95% CI) for a total behavioral score above the cut-off for clinical problems was 0.31 (0.09-1.0), P=0.054.


Lower scores of externalizing behavior in supplemented children supports our previous findings at 3 years, and suggests that iron supplementation may have long-lasting effects on behavioral functions.