Vitamin A Equivalence of Plant Carotenoids in Children

Overview

Our objectives will be to test the following hypotheses and to make the following determinations: (1) The absorption and bio-conversion of provitamin A carotenes taken by children are different between spinach, Golden Rice, and ß-C in oil capsules. (2) The absorption of provitamin A carotenes and their bioconversion to vitamin A are different in children with or without adequate vitamin A nutrition. (3) To define the vitamin A equivalence(s) of dietary spinach, Golden Rice, and a ß-C in oil dose by using an isotope reference method in children with or without adequate vitamin A nutrition and to compare those values with values derived from model based compartmental analysis. (4) To determine the number and time of blood samples needed for future studies in various field settings on the retinol equivalence of a large number of plant sources.

This project is to determine the vitamin A value (equivalence) of dietary provitamin A carotenes from spinach, Golden Rice, and pure ß-carotene (ß-C) in oil. These experiments will be conducted in children (ages 6-8) with/without adequate (marginal deficiency) vitamin A nutrition. As plant provitamin A carotenoids are a major and safe vitamin A source for a vast population in the world, it is essential to determine the efficiency of provitamin A carotenoid (mainly ß-C) conversion to vitamin A. By introducing ß-C into rice endosperm, Golden Rice may directly benefit consumers by providing vitamin A nutrition. Our investigation uses hydroponically grown, deca-deuterium labeled spinach and Golden Rice, synthetic ß-C-d10 and a vitamin A isotope reference, C13 labeled retinyl acetate (13C10-RAc), to evaluate the bioavailability and the bioconversion of plant provitamin A carotenes to retinol as compared with ß-C in oil capsules in vivo. Seventy-two children each will take two meals, breakfast containing 13C10-RAc dose (0.5mg in 0.2g oil capsule) and lunch containing spinach containing 1 mg ß-C (along with white rice), or Golden Rice containing 0.5mg ß-C (along with light colored vegetables), or ß-C oil capsules containing 0.5 mg ß-C in 0.2g oil (along with white rice and light colored vegetables) on the first day of the study. Blood samples will be collected at 1 3, 7, 14, and 21 days after the study doses. The enrichment of labeled ß-C and labeled retinol in human circulation will be determined using advanced liquid chromatography / mass spectrometry and gas chromatography / mass spectrometry. Through the applications of these novel technologies, we will be able to determine the relative biological activities of endogenous carotenoids; that is, the vitamin A value of spinach, Golden Rice, and ß-C in oil capsules for children with/without vitamin A malnutrition. This study will be of importance in planning vitamin A deficiency prevention strategies and also will provide useful information regarding the potential efficacy of a bioengineered crop to provide vitamin A nutrition.