Efficacy of combined iron and zinc supplementation on micronutrient status and growth in Vietnamese infants.

Objective:To evaluate the effect of combined iron–zinc supplementation on micronutrient status, growth and morbidity.Design:Randomized, double-masked, placebo-controlled supplementation trial.Setting:Rural district of Que Vo, in the Red River Delta in Vietnam.Subjects:A total of 915 breast-fed infants aged 4–7 months were included and 784 completed the study.Interventions:The Fe-group received daily and for a 6-month period 10 mg of iron, the Zn-group 10 mg zinc, the Fe–Zn group 10 mg iron+10 mg zinc and the placebo group a placebo. Hemoglobin (Hb), serum ferritin (SF) and zinc (SZn), and anthropometry were measured before and at the end of the intervention. Morbidity was recorded daily.Results:Changes of Hb and SF were higher in both Fe and Fe+Zn groups (respectively 22.6 and 20.6 g/l for Hb; 36.0 and 24.8 μg/l for SF) compared to Zn and placebo groups (Hb: 6.4 and 9.8 g/l; SF: −18.2 and −16.9 μg/l, P<0.0001). SZn increased more in Zn group (10.3 μmol/l) than in Fe+Zn group (8.0 μmol/l, P=0.03) and more in these groups compared to Fe and placebo groups (1.6 and 1.2 μmol/l, P<0.0001). Weight gain was higher in the Zn group. No significant effects of supplementations on growth in length or morbidity.Conclusions:Combined iron–zinc supplementation had a positive effect on iron and zinc status in infants. However, the positive effect of zinc alone on SZn and weight would indicate a negative interaction of iron when added to zinc supplements.Sponsorship:UNICEF New York.European Journal of Clinical Nutrition (2006) 60, 443–454. doi:10.1038/sj.ejcn.1602336; published online 23 November 2005 [ABSTRACT FROM AUTHOR]