Iron Supplementation Beneficial in Healthy, Full-Term Infants

Laurie Barclay, MD

October 06, 2003

Oct. 6, 2003 — Otherwise healthy infants born without iron deficiency benefit from iron supplementation, according to the results of an intervention trial published in the October issue of Pediatrics.

"Iron is required for many relevant central nervous system processes, the most studied being myelination and dopaminergic functioning," write Betsy Lozoff, MD, from the University of Michigan in Ann Arbor, and colleagues. "Evidence for a cause-effect relationship between poorer behavioral/developmental outcome and early iron deficiency remains equivocal."

In this study, healthy, full-term Chilean infants without iron-deficiency anemia at six months were assigned to high- or low-iron groups or to high- or no-added-iron groups. At 12 months of age, the prevalence of iron-deficiency anemia and behavioral and developmental outcomes did not differ between high- or low-iron groups. They were therefore combined to form an iron-supplemented group consisting of 1,123 infants for comparison with the no-added-iron group consisting of 534 infants.

At 12 months, iron-deficiency anemia was present in 3.1% of the supplemented group and in 22.6% of the unsupplemented group. Although global mental and motor test scores were similar in both groups, specific behavioral and developmental outcomes of motor functioning, cognitive processing, and behavior differed between groups. Infants who did not receive supplemental iron processed information more slowly, and they were less likely than supplemented infants to demonstrate positive affect, to interact socially, or to assess their caregivers' reactions.

Unsupplemented infants were less likely to resist giving up toys and test materials or to be soothed by words or objects when upset. Compared with supplemented infants, they crawled somewhat later and were more likely to be tremulous.

"Healthy full-term infants may receive developmental and behavioral benefits from iron supplementation in the first year of life," the authors write. "The results suggest that unsupplemented infants responded less positively to the physical and social environment. The observed differences seem to be congruent with current understanding of the effects of iron deficiency on the developing brain."

The National Institutes of Health supported this study. Abbott-Ross Laboratory provided the infant formula and vitamins.

Pediatrics. 2003;112:846-854

Reviewed by Gary D. Vogin, MD


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