Zinc supplementation for four months does not affect growth in young north Indian children

Our objective in this trial was to assess the impact of daily zinc supplementation on growth in young children. A double-blind, randomized, placebo-controlled trial was conducted in New Delhi, India. We enrolled 2482 children aged 6-30 mo who were supplemented daily with placebo or zinc (10 mg elemental zinc to infants and 20 mg to older children) for 4 mo. At enrollment, all children also received a single dose of vitamin A (104.7 micromol for infants and 209.4 micromol for older children). Weight and length were measured at enrollment and 4 mo later. Weekly visits were conducted by field workers to ascertain morbidity in the previous 7 d. Change in length, weight, length-for-age Z-scores (LAZ), and weight-for-length Z-scores (WLZ) after 4 mo of supplementation were assessed in the zinc and placebo groups. After 4 mo of supplementation, the weight and length gains in the 2 groups did not differ and there was no impact on LAZ, weight-for-age, and WLZ in the 2 groups. There was no substantial effect in any of the subgroups defined for age, income, gender, zinc levels in the crude analysis nor after adjusting for age, gender, income, breast-feeding status, and baseline anthropometric status. Despite successful zinc supplementation reflected in increased plasma zinc concentration and a substantially reduced incidence of diarrhea and pneumonia in zinc-supplemented children, the intervention did not have a beneficial effect on growth.