An insidious form of hunger stalks the world's poor: not starvation, but vitamin and mineral deficiencies, which cost developing nations $6 billion a year in lost productivity while physically and intellectually stunting a third of the planet's children. Geneva-based Global Alliance for Improved Nutrition (GAIN), along with food giants such as Groupe Danone, Unilever, and Cargill, are working to fight this "hidden hunger." Unlike traditional aid campaigns, GAIN looks to build new and sustainable markets for nutritious foods. For example, the group is working with Swedish packaging giant TetraPak to produce a vitamin-rich corn- and soy-based drink dubbed NutriSip, which will be made with local ingredients for distribution in Nigerian schools. "Our job is really to be a catalyst and make sure the private sector delivers food to the poor in the long term," says Bérangére Magarinos, senior manager of GAIN's Investments and Partnerships Program. "If the company defines the project as charitable only, we would not be involved. It's got to go through a business model."