Effects of Daily Zinc, Daily Multiple Micronutrient Powder, or Therapeutic Zinc Supplementation for Diarrhea Prevention on Physical Growth, Anemia, and Micronutrient Status in Rural Laotian Children: A Randomized Controlled Trial

Objectives To evaluate the optimal zinc supplementation strategy for improving growth and hematologic and micronutrient status in young Laotian children. Study design In total, 3407 children aged 6-23 months were randomized to receive either daily preventive zinc tablets (7 mg/d), high-zinc, low-iron micronutrient powder (10 mg/d zinc, 6 mg/d iron, and 13 other micronutrients), therapeutic zinc supplementation for diarrhea (20 mg/d for 10 days per episode), or daily placebo powder; all were followed for similar to 9 months. Anthropometry, hemoglobin, zinc, and iron status were assessed at baseline and endline. Analyses were by intention-to-treat, using linear and modified Poisson regression. Results At baseline, mean (+/- SD) age was 14.2 +/- 5.1 months and stunting and anemia prevalence were 37.9% and 55.6%, respectively. At endline, zinc deficiency in the preventive zinc (50.7%) and micronutrient powder (59.1%) groups were significantly lower than in the therapeutic zinc (79.2%) and control groups (78.6%; P < .001), with no impact on stunting (37.1%-41.3% across the groups, P = .37). The micronutrient powder reduced iron deficiency by 44%-55% compared with other groups (P < .001), with no overall impact on anemia (P = .14). Micronutrient powder tended to reduce anemia by 11%-16% among children who were anemic at baseline (P = .06). Conclusions Despite improving zinc status, preventive zinc and micronutrient powder had no impact on growth. The micronutrient powder improved iron status and tended to reduce anemia among the subset of previously anemic children.