How much Golden Rice is needed to combat VAD?
This is not yet known, and depends on further testing with the events that have been and are being developed. It is important to establish the optimum level of carotenoid delivery consistent with other considerations such as behaviour during harvesting, processing and cooking, bioavailability, and taste. Work with other carotenoid-containing plant foodstuff has shown that provitamin A is relatively stable at high temperatures and hence losses due to cooking are expected to be low. The optimum level at which Golden Rice can play a significant role in helping to combat VAD has not been established yet. The professional and authoritative nutritional advice received by the Golden Rice Humanitarian Board is that even the original 1.6 microgram per gram result of the first-generation Golden Rice would have a positive and beneficial effect on reducingVAD.
Most people affected by VAD have a so-called sub-clinical vitamin deficiency level. As would be expected, these people ingest some provitamin or vitamin A with their foods, but blood vitamin levels are not high enough to sustain a healthy status. What is needed is a top-up of provitamin A to a healthy level. A GR2 line has been selected with provitamin A levels somewhere between the best GR1 and the best GR2 carotenoid levels obtained. This line was selected based on feeding trials that showed that provitamin A contained in such grains was extracted by the digestive system with high efficiency and were capable of fulfilling that top-up function. Regarding stability during processing, it is known that provitamin A is rather stable at high temperatures and hence losses due to cooking are low.
