Provitamin A from Golden Rice is as effective as provitamin A in oil to children

Abstract

Spinach and pure β‐carotene (β‐C) in oil capsule are good sources for vitamin A. A new transgenic product, Golden Rice (GR), is enriched with β‐C genetically. To determine its vitamin A value as compared with spinach or pure 2H8 labeled β‐C (M+8), we conducted a study with healthy Chinese school children (age 7–8y). Intrinsically labeled GR and spinach were obtained by growing plants in a nutrient solution containing ~25% 2H2O. The GR β‐C and spinach β‐C were enriched with deuterium with the highest abundance at M+9. An oil capsule of 13C10 ‐ retinyl acetate (M+10) was taken as a reference dose to determine the β‐C to retinol conversion factors. Serum samples collected from the subjects were analyzed using GC/ECNCI‐MS for the enrichments of labeled retinol by monitoring the isotopes of M+4 (derived from 2H8 β‐C), M+5 (from GR or spinach β‐C) and M+10 (from 13C10 ‐ retinyl‐acetate). By using the response to the dose of 13C10 ‐ retinyl acetate (0.5 mg) as a reference, our preliminary results (using area under the curve of percent enrichment at days 1, 3, 7, 14, and 21 after the labeled doses) showed that the conversions of pure β‐C (0.5 mg), GR β‐C (0.6 mg), and spinach β‐C (1.4 mg) to retinol were 2.0, 2.1, and 7.3 to 1 by weight, respectively. These results indicate that GR can be as effective as β‐C in oil in contributing to the daily vitamin A requirements of children, thus, to improve population‐based vitamin A adequacy.