Sadly, while rice grains contain other important nutrients, they do not contain provitamin A, not even the unpolished grains. Plants produce provitamin A, which is a precursor of vitamin A, as well as other related compounds, called carotenoids. Hence, dependence on rice as the predominant food source unavaoidably leads to vitamin A deficiency, most severely affecting children and pregnant women.
A major goal of the Golden Rice Project is to be capable of supplying the recommended daily intake of vitamin A to
people living in rice-based societies. The tools necessary to achieve this goal are available since the development of an advanced
version of Golden Rice known as GR2.The picture above shows the pleasant orange, translucent colour of GR2, which stems
from an increased accumulation of beta-carotene in the grain as compared to the earlier GR1.
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Golden Rice, which is the result of targeted genetic engineering, offers a partial solution to a world-wide problem. The approach is based on using precursor molecules present in the grain by filling an enzymatic gap in the pathway to beta-carotene production. This pathway is active in rice leaves but not in the grain. Thus, no new substance is being produced. The modification only consists in producing beta-carotene in a tissue where the plant normally doesn't produce it. The reason why it doesn't is because for the plant beta-carotene is only needed in photosynthetic tissues. Beta-carotene accumulation in carrots is the result of a mutation selected by a breeder and not the natural state of carrots, which are either white or dark purple. In the quest for more nutritious or higher yielding crops, farmers and breeders over the last ten-thousand years or so have selected characteristics that are not always of benefit to the plant but to humans, exactly as we're doing now with Golden Rice.
Our goal is to offer a useful tool to ongoing health programs, by increasing the coverage of vitamin supply, especially to remote rural areas. Our hopes are rooted in the fact that seed represent a sustainable approach to biofortifiied crops. Once farmers start growing Golden Rice, funds used to run some supplementation programs (in the form of pills and capsules) could be freed and redirected to other much needed programs. Experience over time has demonstrated that rice will stay a main caloric intake source for billions of people, because it is easy to grow, well adapted for long term storage, and cheap to obtain. Good beta-carotene sources are not grown everywhere where vitamin deficiency is a problem. Moreover, now know that bioavailability of beta-carotene from vegetables is more inefficient than previously thought, and thus the required increase in daily vegetable intake would be economically unattainable for many poor people.