Effect of vitamin A-mineral supplementation on serum retinol and overall nutritional status of school children aged 6-10 years in Wakiso District, Uganda: A randomized controlled trial

Abstract

Introduction: School aged children are faced by many nutritional problems including deficiencies of major micronutrients such as Vitamin A, Iron and Zinc. Vitamin A Deficiency is a public health problem in Uganda and efforts for its control have focused mainly on preschool children and lactating mothers but hardly on the school-age children. Supplementation is one way of improving the micronutrient status of children. Multiple-micronutrient supplementation is envisaged as one of the most cost-effective approaches to addressing the micronutrient problems in children. However, research in this area has been scanty.

Overall Objective: To assess the effect of Supplementation with vitamin A and other micronutrients (Iron and Zinc) on serum retinol and the general nutritional status of school children (6–10 years).

Study design: Primary schoolchildren (6-10 years) selected from three day primary Schools in Wakiso district were randomly allocated to two vitamin A-mineral supplementation groups: A (Vitamin A + Iron) and B (Vitamin A + iron + Zinc) in a randomized double-blind placebo-controlled study design. Serum retinol, weight and height were the parameters monitored in four school terms (16 months). Treatment groups were tested for significance at p < 0.05.

Results: Height for age and weight for age increased in all the groups. Body Mass Index for age increased only in the group that received vitamin A and iron without zinc (group A) but decreased in the others. These changes in nutritional status were, however, not significant. The level of stunting in group A (Vitamin A + Iron) remained at 9.5% while that in B (Vitamin A + Iron + Zinc) reduced from 9.8% to 0%. Underweight reduced by 50% in both groups A and B from 9.5% to 4.8% and 4.9% to 2.4% respectively, but increased by 33% in the control. Wasting on the other hand decreased from 4.8% to 2.4% in group A but increased in the other groups. There were significant increases in mean serum retinol in both groups A and B after supplementation but not in the control. Vitamin A Deficiency reduced from 25% to 20.5% in group A, 22% to 18% in group B but increased in the control from 27.8% to 30.6%. The Vitamin A status was not associated with any of the anthropometric indices: stunting, underweight and wasting.

Conclusion and recommendations: Supplementation significantly reduced the prevalence of underweight but not stunting among the children. Serum retinol levels of the children were significantly increased in the supplemented groups and not in the control. The supplementation, irrespective of the regimen, produced significant eductions in the prevalence of Vitamin A Deficiency. Vitamin A status was not associated with weight-, height- or BMI for age in the school children. Supplementation with multiple micronutrients including vitamin A, Iron and Zinc was found to have beneficial effects in this cohort of school children. More studies are needed to better understand the contribution of schoolchild supplementation with micronutrients in areas where deficiencies of these nutrients are common, before a recommendation to supplement school children with multiple micronutrients can be considered.