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Title: THE POOR BIOAVAILABILITY OF ELEMENTAL IRON IN CORN MASA FLOUR IS NOT AFFECTED BY DISODIUM EDTA.

Author
item TOMAS, WALTER - UNIV/CHILE INT.NUT.F.TECH
item PIZARRO, FERNANDO - UNIV/CHILE INT.NUT.F.TECH
item BOY, ERICK - MICRONUT. INITIAT.,CANADA
item Abrams, Steven

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/22/2003
Publication Date: 2/20/2004
Citation: Walter, T., Pizarro, F., Boy E., Abrams, S.A. 2004. The poor bioavailability of elemental iron in corn masa flour is not affected by disodium EDTA. Journal of Nutrition. 134:380-383.

Interpretive Summary: The best way to decrease iron deficiency in many populations is to add iron to grain products (fortification). However, it is difficult to identify the best way to do this. One common iron source is elemental iron. However, elemental iron is not usually well absorbed, especially from corn flour which is widely used in parts of the world, including Mexico. We used stable isotopes to see if adding a compound called EDTA would help improve the absorption of elemental iron from corn flour. EDTA helps improve absorption of other types of iron. However, we found that the absorption of iron in small children did not benefit in a large way from having the EDTA added to their corn flour. Since EDTA is expensive, this is therefore not a good solution and it appears that elemental iron remains a poor source of iron for fortification of corn flour.

Technical 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 (<45 µm). We conclude that H2-reduced iron powder is an ineffective fortificant in corn tortillas.