Iron and Zinc Absorption from Two Bean (Phaseolus vulgaris L.) Genotypes in Young Women

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• 作者：Carmen M. Donangelo ; Leslie R. Woodhouse ; Sarah M. King ; Gianna Toffolo ; David M. Shames ; Fernando E. Viteri ; Z. Cheng ; Ross M. Welch ; and Janet C. King
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2003
• 出版时间：August 13, 2003
• 年：2003
• 卷：51
• 期：17
• 页码：5137 - 5143
• 全文大小：72K
• 年卷期：v.51,no.17(August 13, 2003)
• ISSN：1520-5118

文摘

Extrinsic and intrinsic iron and zinc labels were used to test iron and zinc absorption from two bean(Phaseolus vulgaris) genotypes, containing normal (common beans, CB) or higher (HFeZnB) ironand zinc concentrations, fed in single meals to young women with low iron reserves. The womenwere divided into two groups, with one receiving a CB test meal (n = 12) and the other, an HFeZnBtest meal (n = 11). The beans were intrinsically labeled hydroponically with ⁵⁵Fe (CB and HFeZnB)and with ⁷⁰Zn (HFeZnB). Concentrations of zinc and iron were 98 and 65% higher, respectively, inHFeZnB as compared to CB, but phytic acid contents were similar. Extrinsic labels were ⁵⁹Fe (CBand HFeZnB), ⁶⁷Zn (CB), and ⁶⁸Zn (HFeZnB). Iron and zinc percent absorption levels were calculatedfrom radio-iron activity in red blood cells and from urinary excretion of zinc isotopes. Intrinsic andextrinsic iron absorption measures were highly correlated (R ² = 0.986) (average extrinsic/intrinsicratio was 1.00). Iron absorption was low (geometric mean < 2%) in both bean types, and total ironabsorbed was not different between types. Intrinsic zinc absorption from the HFeZn beans was higherthan extrinsic absorption (15.2% vs 13.4%, p < 0.05) (average extrinsic/intrinsic was 0.90). Thecorrelation between intrinsic and extrinsic zinc measures was not as high as that for iron (R ² =0.719). Percent zinc absorption levels were similar in both bean types, but total extrinsic zinc absorbedwas 90% higher (p < 0.05) from the HFeZnB meal. Thus, the less expensive and time-consumingextrinsic labeling may be used to screen various varieties of beans for iron bioavailability in humans,but it underestimates zinc absorption by ~10%. Selective breeding for high-zinc bean genotypesmay improve zinc status. However, high-iron genotypes appear to have little effect on iron statuswhen fed alone in single meals to women with low iron reserves.Keywords: Iron and zinc bioavialability; humans; plant breeding; isotope labeling