The Poor Bioavailability of Elemental Iron in Corn Masa Flour Is Not Affected by Disodium EDTA

Abstract

The most sustainable way to eradicate iron deficiency is through food fortification. Elemental iron powders are commonly utilized as fortificants due to their low cost and few sensory problems. However, their bioavailability is unknown. Our goals were to measure the bioavailability of elemental iron in Mexican style corn masa flour tortillas and to evaluate the effects of Na₂EDTA. We used a stable isotope of H₂-reduced iron powder, with and without Na₂EDTA in tortillas prepared with corn masa flour. Two groups of 5- to 7-y-old children (n = 12/group) were fed tortillas to which was added 3 mg/100 g of H₂-reduced ⁵⁸Fe with a mean particle size of 15 μm. In one group, Na₂EDTA was incorporated at a ratio of 1:2 mol/mol. The next day, ⁵⁷Fe ascorbate was given as a reference dose. After 14 d, blood samples were analyzed for isotopic enrichment. When normalized to 40% absorption of the reference dose, the geometric mean (±range 1 SD) bioavailability of reduced iron in tortilla was 3.8% (2.7–5.3). The addition of Na₂EDTA, tended to increase it (P = 0.18) to 5.1% (2.8–9.2). This observed low absorption was compounded by the use of iron isotopes with smaller particle size (mean diameter 15 μm) than typical of commercial elemental iron powder (2-reduced iron powder is an ineffective fortificant in corn tortillas.