Long‐term effects of micronutrient supplementation on intellectual and motor functions

Abstract

Few data exist on long term consequences of micronutrient supplementation on cognitive/motor development. We examined cognitive/motor functioning of 7–9 y old Nepali children (n=694) who received micronutrient supplementation from 12–36 mo of age. In the initial study, children were randomized to daily iron-folic acid (IFA); zinc (Zn); iron-folic acid+zinc (IFAZn); placebo (PL). Follow-up outcomes were: Intellectual function (Universal Nonverbal Intelligence Test - UNIT), executive function (Go/no go, numbers Stroop test, and backward digit span), and motor function (Movement Assessment Battery for Children and a finger tapping test - FTT). Differences in test scores were examined relative to the PL for each supplementation group. In unadjusted analyses, children who received IFA and IFAZn did not score differently on any test compared to the PL group. Children who received Zn scored significantly better on the UNIT (3.03, 95%CI: 0.03, 6.03) and the FTT (2.17, 95%CI: −0.02, 4.37). They also had fewer % failures on the Stroop test (−0.18, 95%CI: −0.36, −0.01). In adjusted analyses, significantly fewer children in the IFA and Zn groups failed the Stroop test (−0.09, 95%CI: −0.17, −0.02 and −0.10, 95%CI: −0.16, −0.03, respectively). We conclude that zinc supplementation between 12–36 mo of age may have modest positive effects on aspects of executive functioning. Support: NICHD and Gates Foundation.