New Scientist (18 August 2012) reports that Golden
Rice can prevent blindness. It contains a precursor to vitamin A deficiency
which blinds an estimated half a million children each year, particularly in
undeveloped countries. The problem is that it is genetically modified, and
therefore there are many opponents to its use.
There is another alternative. A sweet potato,
grown naturally in Uganda, contains a lot more beta carotene than other sweet
potatoes. Beta carotene helps stave off vitamin A deficiency because it is
converted into vitamin A in the body.
About half a million children in Africa and Asia
suffer blindness every year due to the lack of vitamin A in their diet, which
is vital for vision and the immune system. Of those who lose their sight, 66%
die within months.
Aid agencies currently treat vitamin A deficiency with
high-dose vitamin A capsules administered twice a year. However, eating locally
grown food rich in the vitamin would be more practical and sustainable. The orange
flesh of a new strain of sweet potato in Uganda has four to six times more beta
carotene than other sweet potatoes. A two-year project (by the International
Food Policy Research Institute in Washington DC, America) involving 10,000
households in Uganda found that vitamin A intake doubled in women and children
(aged 6 months to 3 years) who ate the new strain of sweet potatoes, compared
with families that ate the regular varieties. By the end of the project almost
90% of the children eating the new strain had prevented vitamin A deficiency,
compared with 50% in the control group (eating other varieties).
Growing the new strain of sweet potato in Uganda
is not controversial because it is grown naturally and locally. However, the solution
for Uganda may not necessarily be a solution everywhere. Some say that as many
different options as possible are required to prevent blindness in children
around the world.
There is another solution, but it is genetically
modified rice called Golden Rice. Golden Rice is genetically engineered to
contain 30 micrograms of beta carotene per gram. Ordinary rice has no beta
carotene. Critics claim that rice is impractical as people would need to eat
huge amounts (as much as 18 kilograms of cooked rice a day) to obtain enough
vitamin A.
A study involving 68 Chinese children refutes the
criticism. Scientists from the University of Boston in Massachusetts, America,
have demonstrated that just 100 to 150 grams of the genetically modified (GM)
rice (about half of the children’s daily intake) would provide 60% of the recommended
daily intake of vitamin A. The children were given beta carotene in the rice,
in pure form in oil, or in spinach (distinguished from the vitamin A already
circulating in their blood). Analyses showed that it took 2.3 grams of beta
carotene derived from rice to make a single gram of vitamin A – only marginally
less efficient than the 2 grams of beta carotene derived from the oil given to
students. Therefore, Golden Rice has the potential to be used widely, despite
objections, to counteract blindness in children.
Opponents to the Golden Rice argue that there are
other options. Proponents say that to address the problem of child blindness,
and potential death, as many options as possible should be considered. They say
that the success of the sweet potato grown in Uganda shouldn’t mean that GM
foods should be definitively or permanently discounted. Other options may take
time, which then places vulnerable children more at risk. They acknowledge that
commercial GM food is risky business but suggest that, as rice is commonly
grown locally in many regions of the world, GM Golden Rice may help an
estimated half a million children a year from blindness and two-thirds of them
from death.
(www.newscientist.com)
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