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Abstract:
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There is increasing concern about potential negative interactions in combined iron and zinc supplementation. The aim of the present study was to determine the dose-response effect of zinc, given as a solution, on iron bioavailability. Twenty-two healthy adult women were selected to participate in the study. Iron, with or without zinc was given as an aqueous solution on d 1, 2, 14, and 15 of the study. Iron bioavailability was measured on the basis of erythrocyte incorporation of Fe-55 or Fe-59 14 d after administration. Subjects received 0.5 mg of iron together with graded zinc concentrations (0-11.71 mg). No significant effect of zinc on iron absorption was found at Zn: Fe molar ratios up to 2: 1. At 5: 1, 10: 1, and 20: 1 molar ratios, a dose-dependent inhibitory effect on iron absorption was observed (28-40% of iron absorption inhibition; one-way repeated-measures ANOVA, F = 4.48, p = 0.02). In conclusion, zinc administration combined with iron in an aqueous solution leads to the inhibition of iron bioavailability, which occurs in a dose-dependent way. This negative interaction should be considered for supplementation programs with both microminerals. |