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

ObjectiveTo assess the effects of zinc and iron–folic acid supplementation on motor and language milestones in Nepali children.MethodsFive 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.ResultsAdjusted 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.ConclusionAfter 1 y, neither zinc nor iron–folic acid supplementation in Nepali children improved the attainment of motor or language milestones.