This is the VOA Special English Agriculture Report.

People who do not get enough vitamin A in their diet may develop night blindness. But in the developing world a lack of vitamin A causes much more serious harm to children. The World Health Organization links vitamin A deficiency to as many as 250,000 child deaths every year.

One excellent source of vitamin A is found in sweet potatoes with orange flesh. Orange sweet potatoes contain high levels of beta-carotene, which the body changes into vitamin A.

Experts say orange sweet potatoes specially bred for growing conditions in Africa could help solve the lack of vitamin A there.

But, first, more people will need to be persuaded to eat them. Jan Low with the International Potato Center, a research organization, says the sweet potato needs a better image in Africa.

JAN LOW: "We do have an image problem with sweet potato in general in sub-Saharan Africa. It is seen as a crop of the poor."

Ms. Low explains that sweet potatoes are mainly grown by poor women to feed their families in case another crop fails. The sweet potatoes commonly grown in Africa have white or yellow flesh. But, more importantly, they are low in vitamin A.

Jan Low took part in a project to study how best to market orange sweet potatoes to Africans. She worked on an information campaign in Mozambique and Uganda.

The campaign included radio messages about the nutritional benefits of the orange sweet potato. They advertised its ability to "fight diseases, make you strong, clear your skin and make you look healthy."

In areas without radio, the campaigners spread the message through community theater. The performances included singing, dancing and storytelling.

And everywhere they went, the campaigners wore orange T-shirts and hats. They even drove orange vehicles. Jan Low says the color of the tuber made it easier to gain public attention.

Dan Gustafson heads the Washington office of the United Nations Food and Agriculture Organization. He points to efforts in the past to increase the popularity of other nutritious crops. He says most of these efforts failed because organizers of the campaigns did not consider what people wanted to eat.

But Mr. Gustafson sees a better chance for the efforts to increase the popularity of the orange sweet potato in Africa. For one thing, except for the color, the vegetable is similar to what people already use.

DAN GUSTAFSON: "I think it is because you have got advertising and you have got a difference that is not radical, that I think it will work."

And that's the VOA Special English Agriculture Report, written by Jerilyn Watson and Steve Baragona. I'm Jim Tedder.

beta-carotene: β-胡萝卜素

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（来源：VOA 编辑：崔旭燕）