b-Carotene in Golden Rice is as good as b-carotene in oil at providing
vitamin A to children1

Guangwen Tang, Yuming Hu, Shi-an Yin, Yin Wang, Gerard E Dallal, Michael A Grusak, and Robert M Russell

The study was carried out in an elementary school in the
Hunan province of China in healthy schoolchildren (with normal
biochemical test results; see below) aged 6–8 y either initially
free of parasitic infection or verified free of infection after
treatment with 400 mg albendazole (GlaxoSmithKline). Most
area residents were local, middle-income, rural, and working
people. Forty-eight percent of the study subjects who were treated
(no side effects) were recruited to participate in the study
1 mo before the start of the study meals. Thus, all of the study
subjects at the time of study were free of parasitic infection by
the laboratory test. Local annual health evaluations were performed
in all children, and biomedical tests were performed
(white blood cell count, hemoglobin count, platelet count, red
blood cell count, and hematocrit).
To estimate the sample size for the study, we used our previous
studies in the United States with spinach or b-carotene capsules
(26, 27) and studies in China (28) for dark-green vegetables for
the power calculations.We found that to determine the differences
for 2 categories—marginal and normal vitamin A intakes—we
would need a sample size of 30 per category, and to evaluate the
effect of food matrix among sources (spinach, GR, and b-carotene
capsules) we would need 10 per group. Considering the possibility
of subject withdrawals from the study, we proposed 36
subjects for the marginal vitamin A group and 36 subjects for the
normal vitamin A group, with 12 each per group for the spinach
group, rice group, and b-carotene capsule group.
From a total of 112 subjects screened, 72 were enrolled in the
study, and sufficient serum samples to facilitate both the HPLC
and gas chromatography–mass spectrometry analyses were
collected from 68 subjects (this varied from 1 to 5 time points
per subject). The anthropometric measurements of the subjects
were within the range of the data reported for all of China for
this age group (29). The study recruitment processes and protocol
were approved by the Institutional Review Board–Tufts
Medical Center in the United States and by the Ethics Review
Committee of Zhejiang Academy of Medical Sciences in China.
Both parents and pupils consented to participate in the study.