Micronutrient deficiencies in Ethiopia and their inter-relationships

Abstract

A nationwide study on the prevalence of xerophthalmia was carried out in 6,636 children aged 6 months to 6 years in all the Regions of Ethiopia except Eritrea and Tigrai which were excluded for security reasons. Bitot's spots were observed in 1.0% of all children with higher prevalence in the pastoral (1.6%) and cropping (1.1%) agro-ecological zones than in the cash- crop (0.4%) and ensete ('false banana', Ensete ventricosum (Welw.) Cheesman) (0.0%) zones. Conjunctival xerosis and Bitot's spots were twice as common in boys than in girls and this was seen in all age groups. One case of corneal xerosis and two cases of corneal scar (0.03%) were also found. Serum retinol levels were deficient (It is estimated that there are three quarters of a million blind persons in Ethiopia. Results of a study of the 721 pupils in the six schools for the blind showed that 70% of the blindness was due to corneal opacity or shrinkage of the eye ball. Measles was implicated as a cause of blindness in 40% of the children while a further 13% regarded "mitch" as the predisposing factor. Mitch is an Amharic term used to describe a wide range of vague illness with fever and measles possibly comprising a large proportion of these cases.A nationwide study on 35,635 school children and 19,158 household members showed that the prevalence of gross goitre was 30.6% and 18.7% respectively while that of visible goitre was 1.6% and 3.2% respectively. Prevalence was significantly higher in females than in males and increased with age more in females than in males. Prevalence increased with increasing altitude. Based on an epidemiological model, the numbers of people suffering from various iodine deficiency disorders have been estimated.In Melkaye village of Hararge Region, a high prevalence of symptoms of vitamin A deficiency were found in 240 children examined: night blindness, 28.7%; Bitot's spots 6.7%; corneal xerosis 0.83%; corneal ulceration/keratornalacia 6.3%; and corneal scars 5.8%. Of the children studied, 30.2% had deficient serum retinol levels (In a study of 14,740 children in Shoa Region of Central Ethiopia, goitre, xerophthalmia (Bitot's spots) and clinical anaemia were observed in 34.2%, 0.91% and 18.6% respectively of the children. Based on a sample of 344 children, the median of most biochemical parameters was within the normal range except for haemoglobin, mean corpuscular haemoglobin concentration (MCHC) and urinary iodine excretion where the median was lower, and mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), and immunoglobulins G and M where it was higher. Many significant correlations were observed and these were used as the basis for the formulation of hypothethes. The anaemia found was not nutritional in origin but due to the effect of infestation with intestinal parasites and malaria.The effect of vitamin A supplementation on the treatment of goitre with iodized oil was assessed in a series of studies in Shoa Region. Iodized oil supplementation significantly reduced goitre size in those who had grade IB goitre (observable when neck extended). After 4 and 7/8 weeks post-treatment, concentrations of thyroxin and that of urinary iodine excretion increased significantly, while those of total triiodothyronine and thyrotropin decreased significantly. Vitamin A supplementation increased serum levels of retinol and retinol-binding protein at weeks 4 and 7/8 but had no effect on goitre size or parameters of iodine metabolism.In a similar study on anaemia, supplementation with iron and folic acid significantly increased levels of haemoglobin, haematocrit, red blood cell count, serum iron, transferrin saturation, ferritin and mean corpuscular haemoglobin concentration and significantly decreased levels of total iron binding capacity and transferrin at 4 and 7/8 weeks posttreatment. Only the increase in red blood cell count and decrease in mean corpuscular volume were significantly greater in those supplemented with vitamin A than those who were not supplemented.In the Gurage area in Central Ethiopia, cultivation, harvesting, yield and processing of ensete were studied in 60 households in six villages. Ensete was propagated vegetatively and has a six-year growing cycle in which it was transplanted three or four times. The yield of ensete food ("ko'cho") was 9.5 tons/yr/ha (6.1 MJ/m 2/yr). Except for cassava, the energy yield of ensete was higher than that from all other crops grown in Ethiopia while the protein yield (11.4 g/m 2/yr) was higher than that of all crops except banana and Irish potato although the protein density is very low (12 g/kg). The pseudostem and corm provide a starchy pulp which is fermented and can be stored for up to 5-7 years in an earthen pit. It can then be prepared for consumption in a variety of ways which have been studied in detail. The mean intake of ensete was 0.55 kg/day and provided 68% of total energy intake, 20% of protein, 28% of iron but no vitamin A. Energy intake from all food consumed was extremely low in Gurage, being only 60% of requirements