Certainly, a high priority for research is an evaluation of the bioavailability and
bioefficacy of the pro-vitamin A contained in Golden Rice.
This research has been severely hampered in the past by the
necessity of producing a sufficient quantity of grain (multiple
kilograms) to be used in feeding trials in accepted model
systems (pig, preruminant calves and ferrets) in safety greenhouses
in Europe and restrictions prohibiting field trials outside
of greenhouses. However, novel analytical methods have
become available (utilizing HPLC-linked electrochemical detection
or deuterium labeling in combination with HPLC and
mass spectrometry) significantly lower amounts of rice. Efforts
are currently underway to allow Golden Rice to be imported
into the United States, where bioavailability investigations
using these techniques can be conducted.