The Effect of Low Dose Iron and Zinc Intake on Child Micronutrient Status and Development during the First 1000 Days of Life: A Systematic Review and Meta-Analysis

Abstract

Adequate supply of micronutrients during the first 1000 days is essential for normal development and healthy life. We aimed to investigate if interventions administering dietary doses up to the recommended nutrient intake (RNI) of iron and zinc within the window from conception to age 2 years have the potential to influence nutritional status and development of children. To address this objective, a systematic review and meta-analysis of randomized and quasi-randomized fortification, biofortification, and supplementation trials in women (pregnant and lactating) and children (6–23 months) delivering iron or zinc in doses up to the recommended nutrient intake (RNI) levels was conducted. Supplying iron or zinc during pregnancy had no effects on birth outcomes. There were limited or no data on the effects of iron/zinc during pregnancy and lactation on child iron/zinc status, growth, morbidity, and psychomotor and mental development. Delivering up to 15 mg iron/day during infancy increased mean hemoglobin by 4 g/L (p < 0.001) and mean serum ferritin concentration by 17.6 µg/L (p < 0.001) and reduced the risk for anemia by 41% (p < 0.001), iron deficiency by 78% (ID; p < 0.001) and iron deficiency anemia by 80% (IDA; p < 0.001), but had no effect on growth or psychomotor development. Providing up to 10 mg of additional zinc during infancy increased plasma zinc concentration by 2.03 µmol/L (p < 0.001) and reduced the risk of zinc deficiency by 47% (p < 0.001). Further, we observed positive effects on child weight for age z-score (WAZ) (p < 0.05), weight for height z-score (WHZ) (p < 0.05), but not on height for age z-score (HAZ) or the risk for stunting, wasting, and underweight. There are no studies covering the full 1000 days window and the effects of iron and zinc delivered during pregnancy and lactation on child outcomes are ambiguous, but low dose daily iron and zinc use during 6–23 months of age has a positive effect on child iron and zinc status.

Child acceptability of a novel provitamin A carotenoid, iron and zinc-rich complementary food blend prepared from pumpkin and common bean in Uganda: A randomised control trial

“…Iron and zinc concentration of BPB was low compared to other studies that developed and tested child acceptability of iron and zinc-rich complementary foods (Konyole et al, 2012;Bauserman et al, 2015). However, there is convincing evidence from a systematic review study that low dose daily iron and zinc intake has a positive effect on iron and zinc status of children, 6 to 24 months old (Petry et al, 2016).…”

Iron Deficiency Anemia and Pregnancy

“…Study results showed that supplementation with iron-folic acid had increased hemoglobin and had a 54% reduction in IDA; the combination of folic acid, zinc, and iron had a 48% reduction, while the combination of folic acid, zinc, iron, and 11 other micronutrients had a 36% reduction, whereas supplementation with folic acid alone had no influence on IDA [84]. The more recent meta-analysis performed by Petry et al [85] found that supplementation with iron or zinc during pregnancy had no effect on birth outcomes, but did show the positive effect of low dose daily iron and zinc use during 6-23 months of age on child's iron and zinc status, especially weight-for-age and weight-for-height [85]. Supplementation is encouraged due to expected improvement in iron blood status.…”

Introducing complementary foods in the first year of life

“…It is clear how the iron intake through breast milk fails to meet these demands. 3 With regard to the timing of introduction of weaning in the past we have witnessed the tendency to wean the baby early (3 th -4 th month of life) in relation to neurological development, suggesting small amounts of homogenised foods (predominantly fruit). 4 Over the years, the evidence revisited this approach, demonstrating that the shift to non-milk foods is indicated for about six months of life in accordance with scientific acquisitions, after comparisons with non-Western cultures, and studies on gastrointestinal maturity.…”