Effect of supplementation with iron, vitamin A and zinc on anaemia levels and nutritional status of school children (6-10 years) in Wakiso District

Abstract

Background: Iron deficiency and anaemia during childhood are associated with adverse outcomes like impaired cognitive and motor development and learning difficulties in children. Consumption of diets low in bioavailable iron, vitamin deficiencies and parasitic infections are among the major causes of anaemia in children. School children are a vulnerable group as their growth demands are high. It has been suggested that supplementation with micronutrients may be the best way to improve the nutritional status of children. Objectives: This study assessed the impact of supplementation with iron+ zinc+vitamin A and iron+vitamin A alone on the anaemia levels and nutritional status of school children from a rural setting. Methods: The study was a randomised, controlled longitudinal trial. A total of 156 children were randomly recruited from three government–aided primary schools and randomly assigned to three treatments namely; iron + vitamin A, iron + zinc + vitamin A and a control. The study took a total period of eight months. Structured questionnaires were used to obtain socio-demographic information and Food frequency Questionnaires (FFQ) and 24 hour food recalls were used to obtain the children’s food intake data. Anthropometric measurements (weight, height, MUAC) plus biochemical measurements on blood samples (ferritin and haemoglobin concentrations) of the children were carried out before and after supplementation. Haemogolobin and ferritin concentrations were measured using the HemoCue and Enzyme- Linked Immuno sorbent Assay (ELISA) methods respectively. Epiinfo was used to generate Z-scores for height-for-age (HAZ), weight-for-age (WAZ) and BMI. Nutritional status of the children was classified according to WHO guidelines using z-score below -2SD. WHO guidelines were also used to classify anaemia and iron deficiency of the children. The Students’ t-test was used to test differences in means. Socio-economic data were presented as percentages and frequencies. In all statistical tests, a p-value of <0.05 was considered significant. Results.The mean dietary iron intake was found to be 6.4 mg/day which is below recommended dietary intake (RDI) for children aged 6-10 years of 10 mg/day. The overall prevalence of stunting was 12.5%; underweight was 10% while wasting was 3.7% at baseline. After intervention there were no reductions in the levels of stunting. There was a slight reduction in the underweight levels of the children however this change was not significant. Comparison of mean nutritional status indicators of the treatment and control groups showed no significant differences (p>0.05). The overall prevalence of anaemia was 11.1% and iron deficiency was 10.3% at baseline. After intervention there was a general reduction in the iron deficiency in all the treatment groups. The percentage of reduction was significantly higher in the iron +zinc +vitamin A group than in the iron + Vitamin A alone group (p= 0.01). There was a slight increase in the haemoglobin levels of the children. The increase was higher in the iron +vitamin A group than in the iron + zinc +viamin A group although the change was not significant (p= 0.35). Conclusion and recommendations: The children were found to have inadequate intakes of iron in their diet. Supplementation with iron, zinc and vitamin A did not result in significant positive change in stunting, underweight and wasting levels of the school children. Supplementation with all the three micronutrients together improved the iron status of the children but did not result in a significant increase in their haemoglobin levels. Primary schools should develop programmes for providing nutritious school meals and nutrition education for the children. The practice of backyard farming for both livestock and crops should be promoted in communities to ensure availability of a variety of iron–rich foods. Poverty alleviation programmes should be instituted to enable communities to afford iron-rich foods for their children. More supplementation studies in school children should be conducted to obtain more conclusive evidence of the effect of micronutrient supplementation.