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Appropriate uses of Vitamin A Tracer (Stable Isotope) Methodology
Vitamin A Tracer Task Force Vitamin A deficiency (VAD) is a public health problem in developing countries and is one of the leading cause of blindness in children. Women in developing countries are also at risk of VAD especially during pregnancy and lactation. VAD is associated with a higher risk of death in preschool-age children because of its role in immunity. Public health programs to control VAD include high-dose supplementation, food fortification, and dietary diversification. New approaches such as biofortification are being explored. Supplementation has resulted in a significant improvement in reducing overt clinical deficiency. However, the effect of supplementation on improving marginal vitamin A (VA) status, which is more prevalent, is more difficult to assess. Populations with marginal VA status are more susceptible to infection, and a single bout of infection can rapidly deplete VA stores in the body without affecting serum retinol concentrations. Tracer dilution techniques have emerged as a select method for estimating total body VA pool size and for answering specific biological questions related to VA metabolism. They can be used to estimate quantitatively the amount of VA retained in the body in response to increased intakes of preformed and provitamin A—whatever the source—and to estimate the impact on total body VA stores. Although tracer methodology is a powerful tool for assessing VA status, and the efficacy and effectiveness of interventions, the costs are not trivial. Therefore, studies must be carefully designed and implemented to obtain meaningful results.
Published: 2004
Cost: $3.50
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