Role of Zinc in Stunting of Infants and Children in Rural Ethiopia

Summary

Stunting is highly prevalent in children in Ethiopia with 57% of infants aged 6-11 mo being affected. The reasons for stunting are poorly understood but zinc deficiency may play a role in its aetiology. The research described in this thesis was carried out in a rural area of Ethiopia. It comprised a cross-sectional study of 305 breastfed infants aged 5-11 mo and their mothers; a double-blind randomised controlled zinc supplementation trial on growth of 200 breastfed infants aged 6-12 mo for 6 mo, in which children were examined at 6 mo at the end of the supplementation period, and 42 mo later; and a study of the mineral, phytate and tannin content of traditional diets of the rural population.

The prevalence of stunting, underweight and wasting of infants aged 5-11 mo was 36%, 41% and 13% respectively. The type, quality and quantity of supplementary foods given to infants were the major factors associated with stunting. Malnutrition was also prevalent among the mothers with 27% being chronic energy deficient (body mass index <18.5 kg/m ²) and 20% being night blind indicating that vitamin A deficiency is a serious problem. Supplementation with 10 mg of elemental zinc daily for 6 mo increased both linear and ponderal growth in both stunted and non-stunted infants and the effect was greater in the stunted children. Zinc supplementation resulted in a markedly lower incidence of anorexia and morbidity from cough, diarrhoea, fever and vomiting in stunted children. When the children were followed up 36 mo after supplementation had been discontinued, the gains in height and weight achieved during zinc supplementation had all but disappeared. The diets of the rural Ethiopian population are relatively high in zinc and iron, but because of the high content of phytate and tannins, the bioavailability of zinc and iron is low. An exception to this is the high content of bioavailable iron and zinc in enjera prepared from fermented cereals, especially from tef.

The findings of this study suggest that stunted children in Ethiopia need a continuous supply of zinc to maintain adequate health and growth. Thus policies and strategies should be developed to address the high prevalence of stunting among children, as stunting is a major barrier to people in rural Ethiopia reaching their full potential.