Supplementation with zinc between meals has no effect on subsequent iron absorption or on iron status of Chilean women

Objective Studies on the effect of zinc (Zn) supplementation on iron absorption and iron status have shown mixed results. We investigated the effect of daily supplementation with 20 mg of Zn for a period of 2 mo on iron absorption and iron status of Chilean women. Methods Forty-four non-anemic, clinically healthy women 35 to 45 y of age were randomly selected to receive daily 20 mg of Zn, as Zn sulfate, or a placebo between meals for a period of 2 mo. Iron and zinc biochemical indicators and iron absorption studies were assessed at baseline and at the end of the study. Iron absorption was measured using the double radioisotopic technique. Results The geometric mean (range ± 1 standard deviation) absorption of iron before supplementation between the Zn-supplemented and placebo groups was similar (31.2, 11.2 ± 86.3, versus 27.4, 14.4 ± 52.2, respectively, P = 0.97). Absorption increased significantly after the 2-mo supplementation period (P = 0.049), but there were no group-wise differences at the end of the trial (34.4, 17.5 ± 67.3, versus 39.8, 20.9 ± 75.8, respectively, P = 0.97). The geometric mean plasma Zn concentrations did not change significantly in either group during the course of the study (P = 0.47). There was no significant effect of Zn supplementation on any of the iron indicators studied. Conclusion Supplementation of 20 mg of Zn between meals for a period of 2 mo had no effect on subsequent iron absorption or iron status of Chilean women.