This investigation protocol uses an isotope reference method to evaluate bioavailability of
ß-C in rice and its bioconversion to vitamin A.
A well-nourished population will be fed hydroponically grown Golden Rice containing ~ 1 mg
of β-carotene at day 8 after a reference dose of vitamin A at day 1. The blood samples will
be collected up to 33 days after the doses. The absorption kinetics will be determined by
tracking both vitamin A and β-carotene in human serum. Blood responses to Golden Rice
β-carotene will be determined and evaluated. The vitamin A value of Golden Rice can thus be
Recently, scientists have genetically engineered "golden rice" that contains 1.6 ug
ß-carotene in a gram of dry rice (12). Since the vitamin A equivalency varies from 2 ug
(oil dose) to 27 ug (vegetable) carotene to 1 retinol equivalent and the equivalency is
matrix dependent, it is necessary to know what the vitamin A equivalency of golden rice
beta-carotene is. The determination of the absorption and conversion of golden rice
beta-carotene is of importance for designing food programs in many rice-eating regions of
the world, where vitamin A deficiency is common.
To evaluate the absorption and intestinal conversion of rice beta-carotene after an acute
dose of golden rice, an intrinsically labeled Golden Rice with a labeled reference dose of
vitamin A are used. We propose to conduct a pilot study on the US adults with normal vitamin
A status (n = 15).
The specific aims of this pilot study are:
1. To determine ß-carotene response kinetics following a meal of golden rice with 0, 5, or
10 g fat (butter);
2. To determine retinol kinetics from the golden rice and from the labeled vitamin A dose;
3. To determine vitamin A value of golden rice ß-carotene in adults with normal vitamin A
status. The determination of the absorption and conversion of golden rice ß-carotene is
of importance for designing food programs in many rice-eating regions of the world,
where vitamin A deficiency is common.
- healthy health
- GI track problems