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Bioavailability of elemental iron powder in white wheat bread


Objective: Iron fortification of wheat flour is widely used. In most cases, elemental iron powders are utilized as fortificants due to their lower cost and few, if any, sensory problems. However, their bioavailability is unknown. We aimed to measure the bioavailability of H2-reduced elemental iron powder in white wheat bread made from 72% extraction flour.

Design: A stable isotope of H2-reduced iron powder (mean particle size 15 μm) was used as fortificant in bread prepared from unfortified wheat flour. In all, 12 5- to 7-y-old children were fed bread with 4 mg of H2-reduced 58Fe /100 g of flour. The next day 57Fe ascorbate was given as reference dose. After 14 days, erythrocytes were analyzed for isotopic enrichment using mass spectrometry.

Results: When normalized to 40% absorption of the reference dose, the geometric mean (±range of 1 s.d.) bioavailability of reduced 58Fe in wheat bread rolls was 6.5% (3.7–11.8).

Conclusions: When compared to previous radioiron studies of ferrous sulfate showing 10% absorption from an identical meal in adult women, the relative bioavailability can be estimated at about 65%. However, the bioavailability of this smaller particle size 58Fe (15 μm) is likely to be higher than that of commercial iron powder (45 μm) although the precise difference cannot be ascertained with current methods. Thus, the bioavailability of commercial elemental iron powders currently used in fortification programs is likely to be substantially lower than that of ferrous sulfate.

Sponsorship: This work was funded in part by Grant No 910313 by Micronutrient Initiative, IDRC, Ottawa, Canada.

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  • Abrams SA, O'Brien KO, Wen J, Liang LK & Stuff JE (1996): Absorption by 1-year-old children of an iron supplement given with cow's milk or juice. Pediatr. Res. 39, 171–175.

    CAS  Article  Google Scholar 

  • Ames SK, Gorham BM & Abrams SA (1999): Effects of high compared with low calcium intake on calcium absorption and incorporation of iron by red blood cells in small children [In Process Citation]. Am. J. Clin. Nutr. 70, 44–48.

    CAS  Article  Google Scholar 

  • Arredondo M, Pizarro F, Walter T & Hertrampf E (1991): Determinacion de ferritina serica por ELISA. Rev. Child. Nutr. 20, 43–55.

    Google Scholar 

  • Bjorn-Rasmussen E, Hallberg L, Isaksson B & Arvidsson B (1974): Food iron absorption in man. Applications of the two-pool extrinsic tag method to measure heme and nonheme iron absorption from the whole diet. J. Clin. Invest. 53, 247–255.

    CAS  Article  Google Scholar 

  • Bjorn-Rasmussen E, Hallberg L & Walker RB (1972): Food iron absorption in man. I. Isotopic exchange between food iron and inorganic iron salt added to food: studies on maize, wheat, and eggs. Am. J. Clin. Nutr. 25, 317–323.

    CAS  Article  Google Scholar 

  • Bjorn-Rasmussen E, Hallberg L & Walker RB . (1973): Food iron absorption in man. II. Isotopic exchange of iron between labeled foods and between a food and an iron salt. Am. J. Clin. Nutr. 26, 1311–1319.

    CAS  Article  Google Scholar 

  • Cook J, Layrisse M, Martínez-Torres C, Monsen E & Finch C (1972): Food iron absorption measured by an extrinsic tag. J Clin. Invest. 51, 805–815.

    CAS  Article  Google Scholar 

  • Dary O (2002): Lessons learned with iron fortification in Central America. Nutr. Rev. 60, S30–S33.

    Article  Google Scholar 

  • Dary O, Freire W & Kim S (2002): Iron compounds for food fortification: guidelines for Latin America and the Caribbean 2002. Nutr. Rev. 60, S50–S61.

    Article  Google Scholar 

  • Hallberg L, Rossander L & Skanberg A-B (1987): Phytates and the inhibitory effect of bran on iron absorption in man. Am. J. Clin. Nutr. 45, 988–996.

    CAS  Article  Google Scholar 

  • Hurrell R (1984): Bioavailability of different iron compounds to fortify formulas and cereals: technological problems. In Iron Nutrition in Infancy and Childhood, ed. A Stekel, pp. 147–178. New York: Raven Press.

    Google Scholar 

  • Hurrell R (1999): Iron. In The Mineral Fortification of Foods, ed. H Richard, pp 54–93. Surrey, England: Letterhead International, Chapter 3.

    Google Scholar 

  • Hurrell R, Bothwell T, Cook JD, Dary O, Davidsson L, Fairweather-Tait S, Hallberg L, Lynch S, Rosado J, Walter T & Whittaker P (2002): The usefulness of elemental iron for cereal flour fortification: a SUSTAIN. Sharing United States Technology to Aid in the Improvement of Nutrition. (Task Force report). Nutr. Rev. 60, 391–406.

    Article  Google Scholar 

  • Hurrell RF (1997): Preventing iron deficiency through food fortification. Nutr. Rev. 55, 210–222.

    CAS  Article  Google Scholar 

  • Hurrell RF (1998): Improvement of trace element status through food fortification: technological, biological and health aspects. Bibl. Nutr. Dieta. 54, 40–57.

    CAS  Google Scholar 

  • Layrisse M, Cook JD, Martinez-Torres C, Roche M, Kuhn IN, Walker RB & Finch CA (1969): Food iron absorption: a comparison of vegetable and animal foods. Blood 33, 430–443.

    CAS  PubMed  Google Scholar 

  • Layrisse M, Martinez-Torres C, Cook JD, Walker R & Finch CA (1973): Iron fortification of food: its measurement by the extrinsic tag method. Blood 41, 333–352.

    CAS  PubMed  Google Scholar 

  • Peña G, Pizarro F & Hertrampf E (1991): Iron supply from bread to the Chilean diet. Rev. Med. Chile 119, 53–757.

    Google Scholar 

  • Roe MA & Fairweather-Tait SJ (1999): High bioavailability of reduced iron added to UK flour [letter]. Lancet 353, 1938–1939.

    CAS  Article  Google Scholar 

  • Walter T, Olivares M, Pizarro F & Hertrampf E (2001): Fortification. In Nutritional Anemias, ed. U Ramakrishnan, pp 153–183. Boca Raton, FL: CRC Press.

    Google Scholar 

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We are indebted to Angélica Letelier for technical assistance. The authors do not have any conflict of interests.

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Guarantor: T Walter.

Contributors: T Walter, who designed, executed and generally supervised the protocols. I took full responsibility for the writing of the manuscript, but all authors reviewed and edited the MS to their full satisfaction. F Pizarro did the iron status lab work and performed the stable isotope incorporation into the dough and supervised the children consuming the bread. SA Abrams performed the enrichment assays in the Mass spectrometer in Baylor, Houston TX. E Boy gave useful advice and directly participated in the initial preparation of the protocols.

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Correspondence to T Walter.

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Walter, T., Pizarro, F., Abrams, S. et al. Bioavailability of elemental iron powder in white wheat bread. Eur J Clin Nutr 58, 555–558 (2004).

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  • elemental iron
  • bioavailability
  • wheat bread

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