Effects of Iron and Zinc Supplementation in Indonesian Infants on Micronutrient Status and Growth

Abstract

In this study the effects of supplementation of iron and zinc, alone or combined, on iron status, zinc status and growth in Indonesian infants is investigated. Micronutrient deficiencies are prevalent in infants in developing countries, and deficiencies often coexist; thus, combined supplementation is an attractive strategy. However, little is known about interactions between micronutrients. In a randomized, double-blind, placebo-controlled supplementation trial, 478 infants, 4 mo of age, were supplemented for 6 mo with iron (10 mg/d), zinc (10 mg/d), iron + zinc (10 mg of each/d) or placebo. Anthropometry was assessed monthly, and micronutrient status was assessed at the end of supplementation. Supplementation significantly reduced the prevalence of anemia, iron deficiency anemia and zinc deficiency. Iron supplementation did not negatively affect plasma zinc concentrations, and zinc supplementation did not increase the prevalence of anemia or iron deficiency anemia. However, iron supplementation combined with zinc was less effective than iron supplementation alone in reducing the prevalence of anemia (20% vs. 38% reduction) and in increasing hemoglobin and plasma ferritin concentrations. There were no differences among the groups in growth. The growth of all groups was insufficient to maintain the same Z-scores for height for age and weight for height. There is a high prevalence of deficiencies of iron and zinc in these infants, which can be overcome safely and effectively by supplementation of iron and zinc combined. However, overcoming these deficiencies is not sufficient to improve growth performance in these infants.

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

“…Most studies would agree upon a negative effect of iron on zinc absorption when both micronutrients are given together as supplements but no effect when both micronutrients or iron alone are added to foods (Whittaker, 1998). Our study is in agreement with the study carried out in Indonesian infants (Lind et al, 2003) that concludes that combined iron-zinc supplementation is significantly less effective to improving zinc status than zinc supplementation alone, whereas two studies conducted in Mexican children (Rosado et al, 1997) and Indonesian infants (Dijkhuizen et al, 2001) did not find any negative impact of zinc supplementation on iron status.…”

“…The lack of effect of any supplement on linear growth is consistent with the studies carried out in low birth weight full-term Brazilian infants supplemented with zinc during the 6 first months of life (Lira et al, 1998) and in 4 monthsold Indonesian infant supplemented with iron, zinc or iron þ zinc for 6 months (Dijkhuizen et al, 2001). A recent study also conducted in Indonesian infants with a similar design shows no impact of zinc or iron or combined ironzinc supplementation on HAZ but improvement of kneeheel length with zinc or iron supplementation alone (Lind et al, 2004).…”

“…Similar efficiency of combined ironzinc (with 20 mg iron and 20 mg zinc) and of supplementation with iron alone on ferritin concentrations is also shown in a study conducted in older Mexican children (Rosado et al, 1997;Allen et al, 2000;Munoz et al, 2000). In contrast, in two recent studies carried out in Indonesian infants with the same doses and duration of zinc and iron supplementation than in our study, the combined iron-zinc supplementation also resulted in improvement of iron status but less effectively than supplementation with iron alone (Dijkhuizen et al, 2001;Lind et al, 2003). The differences in nutritional status of infants, especially in iron status, between the studies may account for the different results.…”

“…A recent study also conducted in Indonesian infants with a similar design shows no impact of zinc or iron or combined ironzinc supplementation on HAZ but improvement of kneeheel length with zinc or iron supplementation alone (Lind et al, 2004). This positive effect of zinc or iron supplements on knee-heel length is not shown in the former study carried out in the same country (Dijkhuizen et al, 2001). A study conducted in 6 to 24-month-old Vietnamese children concludes that 3-month daily micronutrient supplementation containing zinc had no effect on linear growth of the complete sample of subjects but a positive impact on HAZ of children who were stunted before supplementation (Thu et al, 1999).…”

“…The importance of these two micronutrient deficiencies in public nutrition and their likely coexistence in infants in developing countries support that combined supplementation with both iron and zinc would be appropriate and would improve the cost-effectiveness of interventions. However, recent trials show inconsistent results of the impact of association of iron and zinc supplements on micronutrient status (Rosado et al, 1997;Dijkhuizen et al, 2001;Lind et al, 2003) probably related to the nutritional status and the environmental conditions that differs between countries.…”