title: Effect of increasing concentrations of zinc on the absorption of iron from iron-fortified milk.
abstract: The cofortification of milk with iron (Fe) and zinc (Zn) is a strategy used to prevent these deficiencies during childhood. Given that Zn can negatively interact with iron in aqueous solutions, the objective of the present study was to determine the effect of Zn on Fe absorption of milk fortified with Fe and Zn. Twenty-eight women between 33 and 47 years of age, with contraception and a negative pregnancy test, participated in one of two absorption studies. They received on four different days, after an overnight fast, 200 mL of milk (26 % fat) fortified with 10 mg Fe/L, as (A) ferrous sulfate, or the same milk but with graded doses of added Zn, as Zn sulfate of (B) 5, (C) 10, and (D) 20 mg/L (study 1, n = 15). In study 2 (n = 13), subjects received the same milk formulations, but these were also fortified with ascorbic acid (70 mg/L). Milk was labeled with radioisotopes ⁵⁹Fe or ⁵⁵Fe, and the absorption of iron was measured by erythrocyte incorporation of radioactive Fe. The geometric mean and range of ±1 SD of Fe absorption in study 1 were as follows: formula A = 6.0 % (2.8-13.0 %); B = 6.7 % (3.3-13.6 %); C = 5.4 % (2.2-13.2 %); and D = 5.2 % (2.8-10.0 %) (ANOVA for repeated measures, not significant). For study 2, data are as follows: 8.2 % (3.6-18.7 %); B = 6.4 % (2.5-16.4 %); C = 7.7 % (3.2-18.9 %); and D = 5.2 (1.8-14.8 %) (ANOVA for repeated measures, not significant). In conclusion, according to the results from this study, it appears that the addition of zinc up to 20 mg/L does not significantly inhibit iron absorption from milk fortified with 10 mg/L of iron.
authors: Institute of Nutrition and Food Technology, University of Chile, Santiago, Chile. molivare@inta.uchile.cl
authors: Manuel
authors: M
authors: Olivares
authors: Alejandra
authors: A
authors: Wiedeman
authors: Lorena
authors: L
authors: Bolívar
authors: Daniel
authors: D
authors: López de Romaña
authors: Fernando
authors: F
authors: Pizarro
mesh_terms: D000328:Adult; D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism; D002417:Cattle; D002677:Chile; D018592:Cross-Over Studies; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D005296:Ferrous Compounds / Q000008:administration & dosage; D005527:Food, Fortified / Q000032:analysis; D057141:Food, Preserved / Q000032:analysis; D006801:Humans; D007408:Intestinal Absorption; D007504:Iron Radioisotopes; D019266:Iron, Dietary / Q000097:blood / Q000378:metabolism*; D008875:Middle Aged; D008892:Milk / Q000737:chemistry; D015032:Zinc / Q000008:administration & dosage / Q000009:adverse effects*; D019287:Zinc Sulfate / Q000008:administration & dosage
chemical_list: D005296:Ferrous Compounds; D007504:Iron Radioisotopes; D019266:Iron, Dietary; C020748:ferrous sulfate; D019287:Zinc Sulfate; D015032:Zinc; D001205:Ascorbic Acid