Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/2001
Publication Date: 10/20/2002
Citation: HERMAN, S., GRIFFIN, I.J., SUWARTI, S., ERNAWATI, F., PERMAESIH, D., PAMBUDI, D., ABRAMS, S.A. COFORTIFICATION OF IRON-FORTIFIED FLOUR WITH ZINC SULFATE, BUT NOT ZINC OXIDE, DECREASES IRON ABSORPTION IN INDONESIAN CHILDREN 1-4. AMERICAN JOURNAL OF CLINICAL NUTRITION. 2002. v. 76(4). p. 813-817
Interpretive Summary: We studied the absorption of iron and zinc from wheat-flour dumplings fortified with iron sulfate, with or without zinc fortification. Absorption of iron and zinc was good, but zinc sulfate fortification appeared to reduce iron absorption from the wheat-flour dumplings. No such inhibition was noted in dumplings fortified with zinc oxide. The difference in iron absorption (4.4%) represents a relative change of 27%. This is likely to be highly clinically significant in populations that receive a substantial portion of their dietary iron from fortified flour.
Technical Abstract: Iron deficiency is a major nutritional concern in developing countries, and food fortification is a common strategy to treat it. In Indonesia wheat flour is fortified with 60 mg Fe/kg, but because of increasing concerns about marginal zinc status in at-risk populations, consideration is being given to cofortifying flour with zinc. However, little is known about the effect of zinc fortification of flour on iron bioavailability or about the optimum form of zinc supplementation. We measured iron and zinc bioavailability from wheatflour dumplings containing 25 g flour fortified with 60 mg Fe/kg, either alone or with 60 mg Zn/kg as zinc oxide or as zinc sulfate. Ninety children aged 4 - 8 y were recruited and assigned randomly to the 3 groups; 86 completed the study. Iron and zinc absorption were measured with established stable-isotope methods. Iron absorption from the flour fortified with iron only was good (15.9 ± 6.8%), but when corrections were made for hemoglobin concentrations, it was significantly lower from the flour cofortified with zinc sulfate (11.5 ± 4.9%; P < 0.05) but not from the flour cofortified with zinc oxide (14.0 ± 8.9%). Zinc absorption was not significantly different between the zinc oxide and zinc sulfate cofortified flours (24.1 ± 8.2% compared with 23.7 ± 11.2%; P = 0.87). Iron and zinc appear to be highly bioavailable from foods made from fortified flour, but zinc sulfate cofortification may have a detrimental effect on iron absorption.