ARS | Publication request: Quantitative Determinations of Vitamin A Value of Golden Rice Given as Single or Multiple Meals

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 27, 2006
Publication Date: April 18, 2007
Citation: Tang, G., Qin, J., Grusak, M.A., Russell, R. 2007. Quantitative Determinations of Vitamin A Value of Golden Rice Given as Single or Multiple Meals. Micronutrient Forum. W29.

Technical Abstract: To determine vitamin A value of Golden Rice, we grew Golden Rice in heavy water (25 atom %) and produced intrinsically labeled rice to be fed to subjects. Due to our dietary practices (50 to 200 g per meal, uncooked dry weight) and the sensitivity of trace analysis using mass spectrometry, the rice may be given as one meal when the B-C (beta-carotene) level is high (20 ug/g). On the other hand, when the B-C level is below 5 ug/g rice, it should be given as multiple meals to ensure the tracers will be detectable. We designed protocols given either single or multiple meals of rice to evaluate the conversion of Golden Rice B-C to vitamin A in humans. For quantitative determination, a known amount of vitamin A dose with different labeling was given as a reference.The protocol using single meal was designed to give a reference dose of 13C retinyl acetate with the white rice breakfast at day 1 and a Golden rice meal (200 g dry weight, 1 mg B-C) with 10 g fat, low vitamin A, and low B-C breakfast at day 4. A total of 30 serum samples (10 ml each) were obtained at the 0, 5, 8, 11, and 13 hours and day 2 at 0, 5 and 11 hour, day 3 at 0 and 11 hour, day 4 at 0, 5, 8, 11, and 13 hours, day 5 at 0, 5, and 11 hours, day 6 at 0 and 11 hours, days 7, 9, 11, 15, 18, and 25.The protocol using multiple meals was designed to give 13C retinyl acetate capsule and with a standardized breakfast meal and a lunch with cooked golden rice (50 g dry weight, 0.25 mg B-C) with 2.5 g fat at days 1 to 4. At days 5, 6, 7, 8, 11, 18, and 25, a fasting blood sample was withdrawn into a no-additive VaccutainerTM from a forearm vein. The results from the sample analysis tell us that both acute dose and multiple dose studies showed very effective conversion of B-carotene to retinol. Golden Rice is one of the most bioavailable plant foods for vitamin A.