Four scientists have won the 2016 World Food Prize. The scientists are from the International Potato Center. They won the prize for making sweet potatoes healthier. This has benefits for millions of people around the world. The scientists developed sweet potatoes that have extra amounts of Vitamin A. This means they contain more nutrition. One researcher said it was difficult to get farmers to help him with his work. The researcher said: "They told me it was a bad idea." The farmers said their job was to grow more potatoes, kill pests and reduce poverty, not increase nutrition.

The sweet potato could stop people dying from malnutrition. This is not having enough to eat. A lack of Vitamin A is very harmful. Scientists say malnutrition affects over 140 million small children in 118 countries. It also affects over seven million pregnant women. Scientists also say it is a big reason for children becoming blind. Jan Low, from the International Potato Center, said the prize-winning sweet potatoes could make a big difference. Hungry people could get enough Vitamin A. She hopes more scientists will grow vegetables that have extra nutrition.