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Soy protein, phytate, and iron absorption in humans
American Society for Nutrition (1992)
  • Richard F. Hurrell
  • Marcel-A Juillerat
  • Manju B. Reddy
  • Sean R. Lynch
  • Sandra A. Dassenko, University of Kansas Medical Center
  • James D. Cook, University of Kansas Medical Center
The effect of reducing the phytate in soy-protein isolates on nonheme-iron absorption was examined in 32 human subjects. Iron absorption was measured by using an extrinsic radioiron label in liquid-formula meals containing hydrolyzed corn starch, corn oil, and either egg white or one of a series ofsoy-protein isolates with different phytate contents. Iron absorption increased four- to fivefold when phytic acid was reduced from its native amount of 49-8.4 to < 0.01 mg/g of isolate. Even relatively small quantities of residual phytate were strongly inhibitory and phytic acid had to be reduced to < 0.3 mg/g of isolate (corresponding to < 10 mg phytic acid/meal) before a meaningful increase in iron absorption was observed. However, even after removal ofvirtually all the phytic acid, iron absorption from the soy-protein meal was still only half that of the egg white control. It is concluded that phytic acid is a major inhibitory factor of iron absorption in soy-protein isolates but that other factors contribute to the poor bioavailability of iron from these products.
  • Soy-protein isolate,
  • phytae,
  • iron absorption
Publication Date
March 17, 1992
Citation Information
Richard F. Hurrell, Marcel-A Juillerat, Manju B. Reddy, Sean R. Lynch, et al.. "Soy protein, phytate, and iron absorption in humans" American Society for Nutrition Vol. 56 (1992)
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