Vitamin A is vital for preventing childhood blindness, which affects 500,000 children worldwide each year. Greenpeace is against using genetically modified rice which is enriched with a lot more Vitamin A. There are now clinical studies that show the rice is 100-150 grams of rice (half a child's daily intake) provides 60 per cent of the vitamin A that is needed.
More controversial than the naturally bred sweet potatoes is Golden Rice - genetically engineered to contain 30 micrograms of beta-carotene per gram. Ordinary rice has none.
Critics had claimed that the rice is impractical. According to calculations by Greenpeace, people would need to eat huge amounts - as much as 18 kilograms of cooked rice a day - to obtain enough vitamin A, but they are wrong by over 100 times.
A study involving 68 Chinese children demolishes the criticism. Guangwen Tang of Tufts University in Boston, Massachusetts, and colleagues have demonstrated that just 100 to 150 grams of the rice - about half the children's daily intake - provided 60 per cent of the recommended daily intake of vitamin A.
A two-year project involving 10,000 households in Uganda found that vitamin A intake doubled in women and in children aged 6 to 35 months who ate the improved sweet potatoes compared with families that continued eating regular varieties. By the end of the project almost 90 per cent of the kids eating the new strain had escaped vitamin A deficiency, compared with just 50 per cent in a control group.