Overweight impairs efficacy of iron supplementation in iron-deficient South African children: a randomized controlled intervention

Background: Many countries in the nutrition transition have high rates of iron deficiency (ID) and overweight (OW). ID is more common in OW children; this may be due to adiposity-related inflammation reducing iron absorption. Objective: We investigated whether weight status predicts response to oral iron supplementation in ID South African children. Design: A placebo-controlled trial of oral iron supplementation (50 mg, 4 × weeks for 8.5 months) was done in ID 6- to 11-year-old children ( n =321); 28% were OW or obese. BMI-for-age z -scores (BAZ), hepcidin (in a sub-sample), hemoglobin, serum ferritin (SF), transferrin receptor (TfR), zinc protoporphyrin (ZnPP) and C-reactive protein (CRP) were measured; body iron was calculated from the SF to TfR ratio. Results: At baseline, BAZ correlated with CRP ( r =0.201, P