Abstract
Abstract: :
Purpose: Sufficient blood iron levels are essential for optimal development of retinal photoreceptors and neurotransmitter functioning within the geniculostriate pathway and other primary neural systems. Although other benefits derived from breast milk are substantial, the incidence of iron deficiency (15%) and iron deficiency anemia (24%) among breastfed infants is significant and a concern for neurodevelopmental outcome (Innes et al, 1997, Can J Pub Health). Here we test whether iron supplementation (Fe Supp) of breastfed infants between 1 and 6 mo affects hematological status at 6 and 12 mo and visual/neurobehavioral development at 12 mo. Methods: In a double-blind, randomized design, 77 full-term breastfed infants received either 7.5 mg/kg/day of elemental Fe (as ferrous sulphate) or placebo from 1 mo to 6 mo of age. At 12 mo, infants in both groups were tested for refractive status (Welch Allyn SureSight autorefractor), visual acuity (Teller acuity cards) and neurodevelopment (Bayley mental and psychomotor scales). Throughout the study period, complete blood count along with ferritin, superoxide dismutase, RBC catalase, zinc and copper levels were monitored. Results: At study entry (1 mo), both the Fe Supp and control groups did not differ on any biomedical or hematological measures. As expected, by 6 mo, the Fe Supp group showed significantly higher levels of hemoglobin and RBC volume. Although these differences in circulating levels had diminished by 12 mo, analyses revealed that Fe Supp infants showed higher visual acuity (15.0 cpd, z = +1.6 SD vs. 12.8 cpd, z = 1.0 SD) and Bayley psychomotor scores (PDI = 100 vs. 94) than did controls. There were no significant differences between groups in refractive status or Bayley mental scores at 12 mo. Conclusion: Although both groups were within the normal range, our results suggest that early Fe supplementation influences hematological status and enhances later visual and motor development in full-term breastfed infants. Follow-up of these babies will determine whether this effect is persistent.
Keywords: 492 nutritional factors • 623 visual development: infancy and childhood • 620 visual acuity