Bill & Melinda Gates Foundation

Giving Thanks to the Sweet Potato

November 23, 2011

In two days, sweet potato will be served on Thanksgiving dinner tables throughout the United States. Whether boiled or roasted, we should give thanks to this bright orange root crop which is helping African children lead healthier lives.

Africans traditionally eat white or yellow sweet potatoes that are starchier and drier than the orange ones we are most familiar with. Orange sweet potatoes (OSP) have now been adapted to African fields—and tastes. Many organizations are making huge efforts to get farmers to grow these instead. 

But why? It's all in the color. Like carrots—and unlike white and yellow sweet potatoes—OSP contain healthy doses of vitamin A. 

Without vitamin A the body's immunity is lowered, inviting illness. Kids can suffer from night blindness—they can't see when it gets dark, and can eventually go blind.  Up to half a million children tragically go blind this way every year.

All this can be prevented by less than a gram of vitamin A a day.

It's easy enough if you eat a variety of fruits and vegetables every day, or even some eggs, dairy products, or processed foods with extra vitamin A added.

But for millions of poor people, especially in rural areas of Africa, such luxury is out of reach. A monotonous diet of starchy staples is the norm.

When farmers understand that OSP can improve their family's health, however, they're willing to give it a go.

In fact, this was the finding of a project in rural Mozambique which distributed orange sweet potatoes to more than 10,000 poor households in the region.

At the project's end, more than 65 percent of households were growing OSP—many for the first time—and also instead of white or yellow varieties.

The project had amazing results. Thanks to the OSP, women and children got twice as much vitamin A than before, closing the vitamin A deficiency gap in many cases.

All it takes is one small sweet potato to provide a five year old child with all the vitamin A they need that day.

"Often poor people in rural areas of Africa have to rely on outside sources to obtain any sort of goods or services that can improve their health, but this approach puts some power into their hands and it doesn't create any additional work," says Dr. Christine Hotz, who led the study on nutritional impact. "They get it."

OSP is just one of many staple food crops that scientists are looking at in a new light.

Plant breeders have typically focused on increasing crop yield along with drought, disease, and pest resistance. The assumption was that if you tried to increase nutrients, yields would go down. But that's been proven wrong—you can have your yield and nutrition too.  

"This is a big deal," says Dr. Hotz, “it's cheaper, and you get to the root of the problem, because rather than relying on pills or additives, we are finally starting to improve nutrition through better food.”

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