Effects of zinc and iron supplementation fail to improve motor and language milestone scores of infants and toddlers

Objective: To assess the effects of zinc and iron-folic acid supplementation on motor and language milestones in Nepali children. Methods: Five hundred forty-four children 4 to 17 mo old residing in Ishwarpur, Nepal were randomized to receive placebo, iron-folic acid, zinc, or zinc plus iron-folic acid daily. Data were collected at baseline and at 3-mo intervals for 1 y. The main effects of zinc and iron folic-acid supplementation were estimated for motor and language milestones. Crude and adjusted mean cumulative changes in scores from visits 1 to 5 and adjusted rates of change were modeled. Results: Adjusted differences in motor milestone scores from visits 1 to 5 and rates of change were not significantly different for the zinc and non-zinc groups (adjusted β = -0.7, 95% confidence interval [CI] -1.4 to 0.01; adjusted β = -0.1, 95% CI -0.5 to 0.3, respectively). Motor milestones in children receiving and not receiving iron supplements were not significantly different (adjusted β = 0.1, 95% CI -0.7 to 0.8, from visits 1 to 5; adjusted β = 0.1, 95% CI -0.3 to 0.5, for rate of change). Children receiving zinc had a 0.8 lower mean crude change in language score from visits 1 to 5 compared with children not receiving zinc (95% CI -1.3 to -0.3), but the significance was lost after adjustment (adjusted β = -0.2, 95% CI -0.6 to 0.2, for visits 1 to 5; β = -0.1, 95% CI -0.3 to 0.2, for rate of change). No significant difference in motor or language milestone scores from iron supplementation was observed. Conclusion: After 1 y, neither zinc nor iron-folic acid supplementation in Nepali children improved the attainment of motor or language milestones.