Orange sweet potato champions biofortified foods in Africa

Written by Charis Cook

Ugandan children enjoying orange sweet potato. Image by Harvest Plus.
Ugandan children enjoying orange sweet potato. Image by Harvest Plus.

One of the important ways that plant scientists are working to improve the lives of malnourished people in developing countries is through the development of staple crops that improve human nutrition. The most successful of these “biofortified” crops in Africa is the orange sweet potato, which should serve as a model for future enhanced varieties.

According to a study published in the Journal of Nutrition this month, eating orange sweet potato reduces the prevalence of vitamin A deficiency in children in Uganda and Mozambique. Vitamin A is critical for the development of good vision as it is an essential component of rhodopsin, a pigment in photoreceptor cells in the eye. Consequently in poor communities in Africa and south-east Asia, where diets poor in vitamin A are widespread, vitamin A deficiency is the leading cause of preventable blindness. Healthy levels of vitamin A are also necessary for normal organ formation and maintenance. Orange-fleshed sweet potato varieties contain more than 50-fold more β-carotene, which is converted to vitamin A after ingestion, than the yellow or white varieties commonly eaten in African countries.

The study monitored the effects of the Orange Sweet Potato (OSP) project, which was funded by the Bill and Melinda Gates foundation and coordinated by HarvestPlus. The conclusions predict a promising future for the use of biofortified foods bred for increased nutritional value. It was the first large-scale study of its kind, involving 24,000 households from Uganda and Mozambique. Nutritionists and farmers educated communities on the health benefits of orange sweet potato and on growing, storing, and commercializing orange sweet potato crops. Local women were also given recipes and information about hygiene practices.

A Ugandan retailer marketing her orange sweet potatoes. Image by Harvest Plus.
A Ugandan retailer marketing her orange sweet potatoes. Image by Harvest Plus.

When the OSP project started, less than 10% of sweet potato crops in Uganda and Mozambique were orange-fleshed varieties. Two years later, roughly 50% of sweet potatoes grown were orange sweet potatoes. Children and women were eating two thirds more orange sweet potato than previously and in Mozambique, sweet potato provided 78% of their vitamin A uptake. This figure was 53% in Uganda.
The OSP initiative is undeniably a success. HarvestPlus is scaling it up to reach 255,000 households by 2016 and the International Potato Center hopes to introduce orange sweet potato to 600,000 households across 10 countries by 2015.
Future attempts to introduce biofortified crops would be wise to use the OSP model. The initial education phase was crucial for local participation in the project and for sustainable orange sweet potato production. HarvestPlus understood the necessity of communicating to the women who feed their children and grow the sweet potatoes, as well as the men, who control the family income and can commercialize the crop. Additionally, orange sweet potato was embraced easily because children like its taste and appearance, and their mothers were comfortable preparing and cooking it.
Importantly, orange-fleshed sweet potatoes are naturally occurring and the biofortified varieties used for the OSP project were specifically bred by plant breeders. There was no ‘frankenfood’ stigma, unlike the much-hyped golden rice project, which so far has been a non-starter.
The vivid orange of pro-vitamin A. Image by Harvest Plus.
The vivid orange of pro-vitamin A. Image by Harvest Plus.

The use of genetically engineered crops is highly regulated and will never be straightforward, but if the OSP model is adapted, future successes with synthetically biofortified foods may be possible. The only difference between OSP and golden rice is genetic intervention: golden rice also improved vitamin A uptake in children who needed it, and both foods are easily incorporated into normal diets. Presumably, though I was unable to verify this, the orange sweet potato varieties are registered to an owner, but no one seems to have a problem with that – while they do with patented GM plant products like golden rice. While gene transfer between GM rice and other rice crops is possible, a perimeter of a few meters around the crop is enough to prevent this.
Perhaps if a strong emphasis had been placed on delivering high standards of information and education about golden rice, more progress would have been made toward its use in the real world. Future endeavors with biofortified foods, like soybeans containing high omega 3, may make faster progress if they use the OSP project as a model as far as possible.
This post is cross-posted from Weeding the Gems.

Written by Guest Expert

Charis Cook has a PhD in Biological Sciences from Royal Holloway, University of London. She has used her scientific expertise in a variety of science communication roles, including as Senior Business Interaction Manager at the Biotechnology and Biological Sciences Research Council (BBSRC) and Communication Officer for GARNet, a network to support UK plant scientists.


  1. Isn’t it about time we stopped trying to improve the vitamin content of existing crops by genetic engineering, which will always have a stigma attached to it? The use of the vast amounts of money directed towards GMO research would be better spent in more meaningful ways, such as encouraging the production and consumption of foods that have naturally occurring high vitamin content. What has happened to information extension on the basics of agriculture/horticulture to growers? Instead we have governments and research organizations pushing high profile, well-hyped, high-tech solutions that fail more often than they succeed? The world has gone mad!

  2. Did it escape your notice that people are actually doing something to remediate chronic endemic malnutrition? Since malnourished people have less resistance to disease, this reduces disease also. I also have some trepidation about highly modified crops ,but since it is almost impossible to import enough food to make up nutritional deficits anywhere, and since the people who need them most are too poor to afford them if you did, I don’t think anything other than homegrown super food is a reasonable way forward. We should trust the very dedicated and incredibly selfless people who have undertaken this work to exercise every caution needed in the development of such crops

  3. This is really awesome. It makes you wonder why this wasn’t done a long time ago – since this non-GMO high-vit A “Orange sweet potato” has been available for many years. I think that once we all agree that it’s important to try to help poor people overcome hunger and malnutrition, we’ll be able to do it. We need to focus on what works. Elsewhere in Africa, Helen Keller International has been fortifying cooking oils with Vit A with great success. Instead of investing many millions of dollars in high-tech approaches that can be difficult to implement, maybe we should start investing in the scientists and organizations who are working to develop the skills and crops that indigent farmers need to improve the health of their communities. While Golden Rice may be the ultimate answer in some areas, people are dying in the meantime.

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