Hurrell R F, Juillerat M A, Reddy M B, Lynch S R, Dassenko S A, Cook J D
Nestec Ltd., Nestlé Research Centre, Lausanne, Switzerland.
Am J Clin Nutr. 1992 Sep;56(3):573-8. doi: 10.1093/ajcn/56.3.573.
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 of soy-protein isolates with different phytate contents. Iron absorption increased four- to fivefold when phytic acid was reduced from its native amount of 4.9-8.4 to less than 0.01 mg/g of isolate. Even relatively small quantities of residual phytate were strongly inhibitory and phytic acid had to be reduced to less than 0.3 mg/g of isolate (corresponding to less than 10 mg phytic acid/meal) before a meaningful increase in iron absorption was observed. However, even after removal of virtually 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.
在32名人体受试者中研究了降低大豆分离蛋白中植酸盐对非血红素铁吸收的影响。通过在含有水解玉米淀粉、玉米油以及蛋清或一系列不同植酸含量的大豆分离蛋白之一的液体配方餐中使用外源性放射性铁标记来测量铁的吸收。当植酸从其天然含量4.9 - 8.4降低到低于0.01 mg/g分离蛋白时，铁吸收增加了四到五倍。即使是相对少量的残留植酸也具有很强的抑制作用，在观察到铁吸收有显著增加之前，植酸必须降低到低于0.3 mg/g分离蛋白（相当于每餐低于10 mg植酸）。然而，即使几乎去除了所有的植酸，大豆蛋白餐中铁的吸收仍然只有蛋清对照的一半。得出的结论是，植酸是大豆分离蛋白中铁吸收的主要抑制因素，但其他因素也导致了这些产品中铁的生物利用率较低。
