Investigation of factors impacting provitamin A bioavailability and indicators of micronutrient status

Vitamin A is an essential nutrient that is important for visual, reproductive, developmental, and immunological health. Vitamin A deficiency is a major global health concern, impacting 190 million children under 5 years of age. The introduction of provitamin A carotenoid biofortified staple crops may provide a sustainable and cost effective solution for alleviating vitamin A deficiency, particularly in the rural poor who are disproportionately missed by supplementation interventions.;In order to develop biofortified crops that serve as effective vehicles for the delivery of vitamin A to target populations, the investigation of factors impacting the bioavailability of provitamin A carotenoids from plant foods is essential. Cis- isomers of beta-carotene are increased by up to 50% percent during thermal processing of plant foods and are currently assigned a vitamin A value equivalent to 50% that of all- trans beta-carotene. However, the unique bioefficacies of 9- cis- and 13-cis-beta-carotene have not been evaluated using physiological doses in an animal model that metabolizes vitamin A and carotenoids similarly to humans. Bananas are a staple crop, which contain varying levels of provitamin A carotenoids, in many tropical and subtropical regions where vitamin A deficiency persists. It is important to elucidate the impact of matrix effects on provitamin A carotenoid bioavailability in different cultivars and preparations of banana so as to assist plant breeders in biofortification efforts.;The burden of infectious disease is high in many regions where vitamin A deficiency is prevalent. Infection suppresses appetite and alters blood-based indicators of micronutrient status. Few studies have quantified the effect of common infections, such as malaria, on dietary intake. As provitamin A carotenoid biofortification targets are currently set to meet 50% of the EAR in children and based on food intake, infection-related appetite suppression is important to consider. Alterations to micronutrient status indicators can lead to inaccurate estimations of deficiency in populations with high or unknown prevalence of infectious disease. Quantitative investigations into the impact of infection by time stage on blood-based micronutrient status indicators will support the development of a standardized method for adjustment.