The children will be followed for three months after the end of supplementation. Urea breath test will be repeated at the end and at 1 and 3 months after the supplementation. Venous blood (500 µl) will be taken for determination of serum ferritin, transferrin receptor and hemoglobin concentration at the end and after 1 and 3 months of supplementation. Children in the placebo group will be given a three month course of supervised iron supplementation at the end of study period.