Effects of iron and zinc fortified milk supplementation on working memory of underweight poor-urban school children: A randomized double blind controlled trial

Abstract

Background Undernutrition associated micronutrient deficiencies in children are still prevalent in most developing countries. Iron and zinc deficiencies are the most common micronutrient deficiency globally, which significantly contribute deficits in cognitive function. Fortification with iron and zinc has proven successfully in reducing certain cognitive impairments like memory. Objective To determine the effects of milk fortified with iron and zinc on memory of underweight poor-urban schoolchildren. Methods A double blind randomized controlled trial was conducted on 218 underweight poor-urban schoolchildren aged 7-9 years old; 113 children were supplemented twice daily with 27 gram of milk fortified with iron pyrophosphate (12.15 mg) and zinc sulfate (4.4 mg) for three months, 105 children served as controls. Anthropometry measured including bodyweight, height, sitting height and middle upper arm circumference. Memory was measured using digit span backward test in Wechsler Intelligence Scales III. Statistical analyses were performed with SPSS for Windows, version 11.0. Results Baseline data of digit span backward score in iron and zinc group was 2.4 (SD 1.2), and control group was 3.0 (SD 1.8). After intervention, mean digit span backward score in iron and zinc group was 3 .1 (SD 1.2) and in control group 3.0 (SD 1.3). There was no improvement digit span backward score in control group after intervention, compared with 0.7 point improvement in iron and zinc group (P=0.009). Conclusion Milk fortified with iron and zinc improves working memory of underweight poor-urban schoolchildren.

Keywords

• iron, zinc, underweight, memory