WASHINGTON — The sweet potato, that Thanksgiving staple, is starring in a new agricultural revolution that aims not just to produce more food but to create more nutrient-enriched foods that can help save the world's poorest people from blindness, stunted growth and disease.
Agricultural researchers and nutrition and health experts from around the world have gathered in Washington this week for a conference on the benefits of adding essential vitamin A, zinc and iron to ordinary foods such as sweet potatoes, corn, wheat and rice in a process known as biofortification.
The research has been going for more than a decade at universities and research stations around the world lead by the donor-funded organization HarvestPlus. In the next few years, nutrient-rich staple crops such as beans, rice and corn will be ready for farmers to try.
The first HarvestPlus food to go into the marketplace has been the orange sweet potato.
Traditional African sweet potatoes are red outside and white inside. They're not a source of beta-carotene, which the body converts to vitamin A.
Experts estimate that vitamin A deficiency blinds 500,000 preschool children globally each year, and that about two-thirds of them die within months of going blind because the deficiency destroys their immune system and makes them vulnerable to diseases.
Jan Low of HarvestPlus, an American agricultural economist who's worked in Africa for 24 years, has helped get orange sweet potatoes bred to meet the needs of two target countries, Uganda and Mozambique. It took years of work using conventional breeding to get the varieties right.
Orange sweet potatoes now are available in parts of the two countries. HarvestPlus found women willing to make the change once they learned how it would help their children.
"Orange is a great color," Low said. "So we had orange-painted buildings, orange billboards, orange vehicles, and orange hats and T-shirts decorated with the message."
Plant breeding to add vitamin A, zinc and iron is "exactly what we need to improve global health," said William Garvelink, a former ambassador to the Democratic Republic of Congo who heads a new U.S. government program on global hunger called Feed the Future.
"The time has come to mobilize modern agricultural technology to reduce the single largest health problem in the world — malnutrition," he said.
An estimated 3 billion people suffer from not getting enough vitamin A, zinc and iron. Like vitamin A deficiency, not getting enough zinc and iron also weakens the immune system. Low iron also limits children's ability to learn, saps the strength of adults and increases women's risk of dying in childbirth.
For a long time, the green revolution was all about increasing yields. HarvestPlus director Howarth (Howdy) Bouis said that in the 1990s, when he started talking about breeding staple foods that helped meet nutritional needs, breeders said it wouldn't work because yields would be too low. Over time, HarvestPlus found ways to breed in the nutrients without raising the cost of the food or sacrificing other qualities such as drought-resistance.
The fortified staple foods are conventionally bred and aren't expected to be more expensive than the traditional ones they replace. Farmers can save seeds for planting and get the same benefits crop after crop
The organization got started in 2004 with a $25 million donation from the Bill and Melinda Gates Foundation.
HarvestPlus also is developing pumpkin-colored beta-carotene-rich corn. Kevin Pixley of the University of Wisconsin heads the corn research in collaboration with seed companies in Zambia. Orange corn now must go through two years of trials under Zambian regulations. Pixley said they hope to learn from the success story of sweet potatoes when it's ready for use.
Other crops being developed are vitamin A-rich cassava and iron-rich beans for Africa and iron- and zinc-fortified millet, rice and wheat for Asia. Another biofortification program, Agro Salud, improves the nutritional quality of staple foods for Latin America and the Caribbean.
"We've made all this scientific progress," Bouis said. The next step is demonstrate that the food will get used and then scale up.
In the 1980s, 25 percent of U.S. foreign aid was for agriculture. Last year, it was 1 percent. The World Bank's share of development aid targeted for agriculture also declined.
Feed the Future, on its website, said not only the U.S. but also developing countries and donors have been giving less money for agricultural development in recent decades, "despite new threats such as the decline in soil fertility and the challenges of climate change."
Garvelink said the U.S. government has supported HarvestPlus from its beginnings in 1994.
President Barack Obama in September pledged $3.5 billion over three years for development aid focused on small farmers. The government also expects innovation from the private sector and universities on food production.
Staple crops should deliver nutrients because they're the main source of food for the vast majority of the world's people, Garvelink said. Other challenges ahead will be how to grow more food for a growing population on the same amount of land — in order to spare the rain forests — and how to do it in a world that will have less water.
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