GM foods engineered to contain high levels of nutrients could be a neat solution to micronutrient deficiencies in poor countries, but there are many scientific, social and political hurdles.
The UN estimates that more than half the world's population is nutrient deficient. People may consume enough calories but their food might not contain enough nutrients.
The quest to develop fortified genetically modified (GM) plants has yielded mixed results. 'Golden Rice', rich in beta-carotene, has met with anti-GM, political and technological obstacles and has yet to be widely introduced in developing countries.
Others, such as the BioCassava Plus programme which aims to develop cassava with boosted levels of iron, zinc, protein, vitamins, and resistance to plant viruses, are well underway but face similar barriers.
Other crops highlight the need for nutritional tests. A calcium-rich carrot is no use unless the calcium is effectively absorbed by the people eating it. "None of these improvements are any good until we actually show they're good in the food supply," says Kendal Hirschi, creator of calcium rich carrots.
There are also practical issues — nutrient-rich crops cost more than non-modified versions meaning that those most of in need of them cannot afford them. Hirschi is trying to do a deal with a large food company, the profits of which could fund its distribution in developing countries.
But many scientists remain confident that such obstacles will be overcome. "Biotech will, in time, become the new conventional agriculture. The question is: how long will it be until that happens," says Val Giddings, president of Prometheus Agricultural Biotech.