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United States Department of Agriculture

Agricultural Research Service

Title: Algorithm for Estimating Zinc Absorption from Whole Diets

Authors
item Beisiegel, Jeannemarie
item Hunt, Janet

Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: December 1, 2004
Publication Date: March 4, 2005
Citation: Beiseigel, J.M., Hunt, J.R. 2005. Algorithms for estimating zinc absorption from whole diets [abstract]. The Federation of American Societies for Experimental Biology Journal. 19(4):A456.

Technical Abstract: Algorithms to predict fractional Zn absorption (FZA) and total Zn absorbed (TZA) were developed from measurements of Zn absorption from whole diets. Data included studies measuring Zn absorption of healthy adults from three or more consecutive meals extrinsically labeled with Zn isotope. Diets (n = 28 from 11 studies) fitting these criteria contained 30 - 134 mg protein, 0.17 - 5.1 g phytate, 3.4 - 22 mg Zn, 1.1 - 36 molar ratios of phytate:Zn, 0.12 - 2.1 g Ca, and 5.4 - 27 mg Fe. Dietary variables were normalized to 2,500 kcals to predict FZA (0.14 - 0.49) and TZA (1.7 - 6.0 mg). Individual, logarithmic, and interaction terms were examined for best-fit linear regression models of FZA [Logit FZA = 1.06 - (0.258 * g phytate) - (0.535* ln (mg Zn)) + (0.373 * g Ca) - (0.273 * ln (mg Fe)); R2 = 0.83; p < 0.0001] and TZA [ln (TZA) = 1.16 - (0.192 * g phytate) + (0.0709 * mg Zn) + (0.166 * g Ca) - (0.301 * ln (mg Fe)); R2 = 0.84; p < 0.0001]. Variability in FZA was explained by phytate (62%, partial R-square), Zn (12%), Ca (7%) and Fe (2%). For TZA, zinc explained 43%, phytate 34%, Ca 3%, and Fe 4% of the variation. Protein lent no predictive power to either model. In a previous model, total Zn and phytate:Zn explained 41% of FZA variability from 15 diets (IZiNCG, Food Nutr Bull 2004;25:S94). That model explained 64% of FZA variability from these 28 diets, whereas the new model explained 83%. Such algorithms enable easy estimation of zinc absorption from whole diets.

Last Modified: 10/20/2014
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