That's the title of Chapter 5 of Unnaturally Delicious, which discusses a variety of efforts to combat malnutrition in the developing world by breeding crops with higher vitamin and mineral content.
I talk about the organization Harvest Plus, and about one of my former students Abdul Naico who's back home in Mozambique working to increase adoption of sweet potatoes that are higher in beta carotene. Here are a couple pictures he sent me.
While the efforts of Harvest Plus and other organizations have utilized conventional breeding techniques to create, for example, "high iron beans" in Rwanda, others have used biotechnology. The most famous example is the work of Ingo Potrykus, who graciously answered some questions for me about golden rice, which contains a daffodil gene so that the rice produces beta carotene (which the body converts to vitamin A).
The Golden Rice Humanitarian Board shared the following photos with me.