On Fri, 25 Feb 2000 15:06:13 -0600, E. Ann Clark wrote:
>Consider, for example, one of the most heavily promoted magic bullets - golden
>rice, enriched with Vit A. This seems, on the surface, to be a completely
>defensible use of biotechnology. Vandana Shiva recently released a piece on
>The rice is being promoted as a cure for blindness since Vitamin A
>deficiency causes vision impairment and can lead to blindness . According
>to the UN, more than 2 million children are at risk due to Vitamin A
Dr. Shiva has made at least two substantial errors in his piece,
serious enough that they reduce the credibility of an otherwise
>Vitamin A from native greens and fruits is produced without irrigation and
>wastage of scarce water resources. Introducing Vitamin A in rice implies a
>shift from water conserving alternatives for Vitamin A to water a intensive
>system of production since so called high yielding rice varieties are
>highly water demanding. Vitamin A rice will therefore lead to mining of
>ground water or intensive irrigation from large dams with all the
>associated environmental problems of water-logging and salinisation.
I have never worked in Asia, but have worked with about 7,000 hectares
(17,000 acres) of rice in the US, and to a much lesser extent in Latin
America. Dr. Shiva addresses this issue here as if rice will be grown
to replace native vegetables, yet elsewhere he bemoans the loss of
traditional rice cultivars to the new yellow rice.
Part of the problem is that people are simply not eating the vegetable
sources of vitamin A. I have encountered this as a common phenomenon in
much of Latin America and the Caribbean. The logic is that yellow rice
will replace white rice, is it not? And while there are people who may
try to grow it as upland rice, I would assume that the majority of
growers will already be producing paddy rice, and already using
substantial volumes of water. The change in water use from the
introduction of yellow rice is likely to be minor, but the change in
nutrient intake of people eating the rice is likely to be significant.
>Since rice is a staple eaten in large quantities in Asian societies,
>vitamin A rice could lead to excessive intake of vitamin A especially among
>those who do not suffer from vitamin A deficiency. Excess vitamin A can
>lead to hypervitaminosis A or vitamin A toxicity.
This statement is as wrong as it can get. Beta-carotene is *not*
vitamin A, and can not cause hypervitaminosis A. Lucky for me, given
that I consume industrial quantities of carrots, squash, and sweet
potato! Carotene must be converted by the body to vitamin A, and
because it is fat soluble, the body can store it for long periods of
time. The worst that can happen is that your skin tends to turn
yellow-bronze, and in fact this is the operative principle of several
brands of "tanning" pills sold to the pink folks in North America and
Europe. This is an absolute non-issue in the yellow rice discussion.
Dr. Shiva's most legitimate point is the narrowing of the gene pool to
be engendered by introduction of such a rice. That's a trend
well-entrenched since long before genetic engineering, so it's not
really reasonable to attribute the problem to GMOs. Serious problem, to
be sure. But so is blindness in the developing world.
Given that a huge percentage of kids *die* within 2-4 years of going
blind from lack of vitamin A, this is more than an academic discussion.
In the English Caribbean there is an old expression that says, "The
rich man says 'Ripe mangoes have worms.' The hungry man says, 'Let's
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