title: Zinc inhibits nonheme iron bioavailability in humans.
abstract: 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 55Fe or 59Fe 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.
authors.affiliation: Institute of Nutrition and Food Technology (INTA), University of Chile, Macul 5540, Casilla, Santiago, 138-11, Chile.
authors.forename: M
authors.initials: M
authors.lastname: Olivares
authors.forename: F
authors.initials: F
authors.lastname: Pizarro
authors.forename: M
authors.initials: M
authors.lastname: Ruz
mesh_terms: D000328:Adult; D001682:Biological Availability; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007501:Iron / Q000008:administration & dosage / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D007504:Iron Radioisotopes / Q000378:metabolism; D008875:Middle Aged; D012996:Solutions; D015032:Zinc / Q000008:administration & dosage / Q000502:physiology*
chemical_list: D007504:Iron Radioisotopes; D012996:Solutions; D007501:Iron; D015032:Zinc