Vitamin a Fortification Efforts Require Accurate Monitoring of Population Vitamin A Status to Prevent Excessive Intakes

Eradicating vitamin A deficiency and its related sequelae are important to ensure global health. Various vitamin A status indicators are available, but the most commonly used are not sensitive to changes in body reserves of vitamin A, which concentrate in the liver. Serum retinol concentrations can be misleading in some groups of individuals because of lack of sensitivity to total liver reserves. In addition to vitamin A supplementation to preschool children, many countries add preformed vitamin A to a variety of foods in the process of fortification. Indirect indicators that work in the excessive to hypervitaminotic range of liver reserves are needed to monitor such programs. High liver stores have been determined in countries with on-going sugar fortification programs. The retinol isotope dilution test, using deuterium or 13C, is the only current indirect indicator that works in the excessive range of liver reserves. Evaluating population vitamin A status needs to move beyond the measurement of serum retinol concentrations to ensure that we are not tipping the vitamin A scale too far in the wrong direction with the implementation of multiple interventions in the same population groups.