BACKGROUND: Iron deficiency limits the neurodevelopmental potential of more than 200 million children each year. Iron therapy is typically started when iron deficiency anemia is first diagnosed after screening for anemia or detection of clinical symptoms of iron deficiency anemia at 12 months of age. But iron started at this time does not fully correct earlier iron-deficiency-mediated brain dysfunction, underscoring the need for low-cost, easily implementable adjunct therapies to iron to treat or prevent this dysfunction in high-risk populations. GAP Supplementation with the nutrient choline lessens damage to the hippocampus from early-life iron deficiency in pre-clinical models and improves hippocampus-mediated memory in children with Fetal Alcohol Spectrum Disorders. Choline has not been tested in children with iron deficiency anemia, despite strong pre-clinical and clinical evidence supporting a benefit to brain development. HYPOTHESIS: Infants with iron deficiency anemia who receive iron and nine months of daily choline supplements will have better scores on specific neurobehavioral tests of recognition memory than infants who receive iron and placebo. METHODS: This randomized, double-blinded, placebo-controlled clinical trial will randomize 300 6-month-old infants with iron deficiency anemia at Mulago Hospital, Kampala, Uganda, to iron plus choline or iron plus placebo to test the effect of choline on hippocampus-specific and global neurobehavioral outcomes after nine months. RESULTS: Pending IMPACT: If our hypothesis is correct, choline could be added immediately to standard-of-care treatment for iron deficiency anemia. This intervention could safely mitigate the brain dysfunction of early-life iron deficiency that is often undiagnosed until the hippocampal critical window is closing. This simple, low-cost nutrient could thus have life-long benefit for both individuals and the economic and social prosperity of entire regions.