Vitamin A deficiency is widespread in Sub-Saharan Africa (WHO, 2009) and is a cause of xerophthalmia, blindness, night blindness, impaired growth, weakened immune systems and increased risk of death due to infection among children (West, 2002). Among women in pregnancy, vitamin A deficiency may also contribute to increased risk of morbidity, increased risk of neonatal mortality, and nightblindness (West 2002). As a result, vitamin A deficiency contributes importantly to the burden of disease in this region (Black et al., 2008). HarvestPlus proposes to reduce the risk of vitamin A deficiency in at-risk populations through the introduction of improved crop varieties biofortified with provitamin A (Bouis et al., 2011). Zambia was selected as a country that might benefit greatly from the introduction of provitamin A rich maize.
In Zambia, over half of children under five years of age are considered to be vitamin A deficient, as indicated by low plasma retinol concentrations (NFNC/CDC, 2004). Plasma retinol, however, is a biochemical indicator of vitamin A status that is altered by current infection and the presence of infection should be corrected for when interpreting plasma retinol results (Thurnham et al., 2003). To better evaluate the potential impact of food-based vitamin A interventions, including biofortification and food fortification, information on the adequacy of vitamin A intakes and of the intake of food vehicles for these interventions is required. Relatively little information on dietary intakes of food and adequacy of micronutrient intakes combined with biochemical assessments of micronutrient status exist in Sub-Saharan Africa. Further, the available data on the prevalence of vitamin A deficiency derived from plasma retinol measures have not accounted for the presence of infection. More accurate estimates of the prevalence of vitamin A deficiency, and its dietary causes are thus required.
Reliable estimates of population vitamin A status and dietary intake patterns is critical for the appropriate design of interventions to correct dietary deficiencies. Fortification of select food products with vitamin A (i.e., margarine, sugar) has already been implemented in Zambia, while the fortification of maize flour and the biofortification of maize or other staple food crops with vitamin A and other micronutrients are considered as additional strategies. The potential for these strategies to improve vitamin A intakes will partly depend on the access to and consumption of these products by those at greatest risk of deficiency. These factors also require quantification.
HarvestPlus proposed to undertake a comprehensive background nutritional survey in rural Zambia to inform on the potential impact of provitamin A biofortified maize. This survey was carried out in collaboration with the National Food and Nutrition 2
Commission (Lusaka, Zambia) and the Tropical Diseases Research Centre (Ndola,