In Ethiopia and several other developing countries, stunting is very predominant but the reason is poorly understood. Zinc is very important for growth and development but in such countries their diets often don’t contain zinc in appropriate quantities or of necessary bioavailability. Therefore, zinc deficiency might play a major role in stunting. The objective of this study is to determine whether the low rate of linear growth of healthy breastfed infants in a rural village in Ethiopia can be improved by zinc supplementation.

A randomized, placebo-controlled and double-blind trial was conducted on apparently healthy breastfed infants aged 6-12 months. 100 non-stunted (length-for-age, Z score < -2) were coordinated for age and sex with 100 randomly selected stunted (> -2) infants. Infants, both stunted and non-stunted, were matched by sex, recumbent length (within 3 cm) and age (within 2 months) for random task, to receive a zinc supplement (10 mg zinc sulphate per day) or placebo for 6 days a week for 6 months.

The results of the trial stated the following:

• The length of stunted infants increased more significantly (p<0.001) with zinc supplementation (7.0 cm) than with placebo (2.8 cm). The effect was greater (p<0.01) than in non-stunted infants (6.6 vs 5.0 cm for the zinc and placebo groups respectively, p<0.01).
• Zinc supplementation increased the weight of stunted children (1.73 vs 0.95 kg for the corresponding placebo group, p<0.001) and of non-stunted children (1.19 vs 1.02 kg for the corresponding placebo group, p<0.05).
• Zinc supplementation caused an evidently lower prevalence of anorexia and morbidity from fever, cough, diarrhoea and vomiting in the stunted children.
• The total number of these conditions in each child was 1.56 and 1.11 in the stunted and non-stunted zinc supplemented children versus 3.38 and 1.64 in the stunted and non-stunted placebo-treated children, respectively.
• The concentrations of zinc in serum and hair of stunted infants, who were not supplemented with zinc, were lower than the corresponding concentrations of zinc in serum and hair of their non-stunted counterparts at the end of the intervention period.

The study concluded that combating zinc deficiency can increase the growth rate of stunted children as compared to non-stunted infants.

Source: Umeta M, West CE, Haidar J, Deurenberg P, Hautvast JG. Zinc supplementation and stunted infants in Ethiopia: a randomised controlled trial. Lancet. 2000 Jun 10;355(9220):2021-6. doi: 10.1016/S0140-6736(00)02348-5. PMID: 10885352.