Effect of daily and weekly micronutrient supplementation on micronutrient deficiencies and growth in young Vietnamese children

Background: Micronutrient deficiencies remain common in preschool children in developing countries. Interventions focus on single micronutrients and o ften lack effectiveness. Weekly instead of daily supplementation may improv e effectiveness. Objective: The efficacy of weekly and daily supplementation in reducing ane mia prevalence and in improving the zinc, vitamin A, and growth status of 6 -24-mo-old Vietnamese children was investigated. Design: In this double-blind, placebo-controlled trial, the daily group (n = 55) received 8 mg elemental Fe (as iron sulfate), 5 mg elemental Zn (as z inc sulfate), 333 mu g retinol, and 20 mg vitamin C 5 d/wk for 3 mo. The we ekly group (n = 54) received 20 mg Fe, 17 mg Zn, 1700 mu g retinol, and 20 mg vitamin C once a week. PI third group (n = 54) received a placebo only. Venous blood samples were collected at the start and end of the supplementa tion period and anthropometric measurements were taken at the start and 3 m o after the end of supplementation. Results: At baseline, 45.6% of subjects had hemoglobin concentrations <110 gn, 36.3% had zinc concentrations <10.71 mu mol/L, and 45.6% had retinoI co ncentrations <0.70 mu mol/L. Hemoglobin, retinol, and zinc concentrations o f both the weekly and daily groups increased similarly compared with the pl acebo group (P < 0.001). There was no significant difference in growth betw een the supplemented groups and the placebo group. However. the height-for- age of subjects stunted at baseline increased with z scores of 0.48 (P < 0. 001) and 0.37 (P < 0.001) for the daily and weekly groups, respectively. Conclusions: Weekly and daily supplementation improved hemoglobin, zinc, an d retinol concentrations similarly. Neither intervention affected growth of the overall population, but growth of children stunted at baseline was imp roved through both types of supplementation.