Enhancing brain development by early iron supplementation of African infants: An enabling pilot study

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Iron is crucial for brain development and early deficiencies during infancy can cause irreparable damage. Figures from the latest Global Burden of Disease analysis estimate that iron deficiency is more common than all other micronutrient deficiencies combined. This burden is concentrated in sub-Saharan Africa and South Asia. Breast milk contains very little iron, so babies draw upon iron stores laid down in their liver during late foetal life. However, the babies of iron deficient mothers are born with a limited endowment of iron and can rapidly develop iron deficiency. We have recently shown that, by 5 months of age, almost 95% of rural Gambian infants have circulating iron levels below the lower limit of the US reference range. This indicates that these babies are profoundly iron deficienct. The American Academy of Pediatrics (AAP) recommends iron supplementation in exclusively breastfed infants beginning at 4 months of age. AAP also recommends that babies born prematurely start supplementation at 2 weeks. Yet prior and on-going trials of iron supplementation in low-income settings have commenced supplementation much later (eg 8-9m in a large on-going trial in Bangladesh). Our data suggest that this will be too late to prevent early iron deficiency from impairing brain development. We therefore propose a large randomised controlled trial of early iron supplementation starting at 6wks of age. In preparation for such a trial we need to conduct preliminary studies addressing the following questions: Can we effectively enhance circulating iron levels in early infancy by giving daily iron drops? Can we achieve this without undermining duration of exclusive breast feeding? Might the iron alter the balance of the babies' gut microbial flora and thereby cause diarrhoea? Might iron supplementation impair the absorption of zinc and copper and hence require a triple supplement?These questions will be tested in a small enabling study that will inform the design of the intended full trial.