Orange sweet potato champions biofortified foods in Africa

Two Ugandan children dig in to a plate of orange sweet potato (Credit: HarvestPlus)

According to a study published in the Journal of Nutrition this month, eating orange sweet potato reduces the prevelance 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 commercialising orange sweet potato crops. Local women were also given recipes and information about hygiene practices.

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 are scaling it up to reach 255 000 households by 2016 and the International Potato Centre 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 commercialise 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 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 endeavours with biofortified foods, like soybean containing high omega 3, may make faster progress if they use the OSP project as a model as far as possible.

Teaching resource: Plants, food and human health: You are what you eat? presentation for children and students from The Plant Cell teaching resources team.

Image credit: both images from HarvestPlus on Flickr.

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