Effect of iron supplementation on serum zinc status of lactating women in Addis Ababa, Ethiopia.

Abstract

OBJECTIVE: To evaluate the impact of daily and weekly iron supplementation on serum zinc status among anaemic lactating mothers. DESIGN: A randomised iron intervention controlled trial. SETTING: Seven urban slum communities of Addis Ababa. SUBJECTS: Phase one of the study involved 207 anaemic lactating women assigned into two intervention groups; the daily (N=71) and weekly (N=71) Iron supplemented and the control group (N=68). Supplementation with 60 mg tablet containing 300 microg ferrous sulphate and 400 microg folic acid was done for three months while the control group was n otsupplemented. Phase two involved 53 participants systematically drawn from phase one. Main outcome measures: Haemoglobin from all subjects and serum zinc and ferittin levels following three months supplementation. Zinc status based on serum zinc value of less than 10.7% micromole/L. RESULTS: The mean baseline characteristics and serum zinc of the women at baseline were similar, overall marginal zinc deficiency prevalence was 11.3% and no zinc deficiency was detected. Following supplementation, zinc deficiency was detected in the supplemented groups but not in the control group. The mean serum zinc significantly changed in both supplemented groups while no change was observed in the control group. The reduction in the mean serum zinc was significantly higher in the daily than in the weekly supplemented group. CONCLUSION: Iron supplementation impacts negatively on serum zinc status (exacerbates zinc deficiency) and hence, its contribution to zinc deficiency deserves further investigation especially in the context of the on-going promotion of double fortification strategies that involve iron.