A couple weeks ago, we were lucky enough to set up a Skype call with Tawanda Muzhingi, of the International Potato Center (IPC) in Kenya. Despite the time difference and a couple “quirks” of international video calls, we had a fruitful discussion around Tawanda’s work in the fascinating field of biofortification, centered around the nutrient-rich orange-flesh sweet potatoes that he’s been working to distribute among farmers across Sub-Saharan Africa.
What’s more, Tawanda got his PhD in Biochemical and Molecular Nutrition and his MS in Nutrition Science from our very own Tufts University – it was all at once impressive, reassuring, and totally expected to find out that Friedman grads go on to do exciting work like his.
The idea behind biofortification is simple: improve food crops by upping their nutritional value. But biofortification in general is a pretty broad domain – Tawanda was quick to explain that although the term can indicate both conventional plant breeding and genetic modification, his work deals exclusively with conventional breeding, at least for now. The most notorious examples of nutritionally-guided GM crops are probably the most well-know examples of biofortification as a whole – think of golden rice – but there are many more examples of traditional breeding programs for nutritional improvement.
The GM approach is a hot topic that has been beaten to death in the mainstream media, and certainly has both benefits and detriments, but the orange-flesh sweet potato initiative manages to sidestep any such pitfalls by providing extra vitamin A (in the form of ß-carotene) as part of a culturally-incumbent diet. Although here in the United States, we’re used to our sweet potatoes bright orange interior, Sub Saharan Africans and many Asians have tended to prefer white-fleshed sweet potatoes. Tawanda’s project aims to convince farmers to switch to the IPC’s hybrid sweet potato, which combines the vitamin A-rich orange trait from North Carolina sweet potatoes with climactically- and regionally-appropriate varietals from various regions in Africa. By doing so, you end up with a best-of-both-worlds scenario: nutritional benefits without the sensitivity surrounding trying to get GM crops in to use.
The approach of the IPC recognizes the need for a new crop to fit in with the existing system. To that end, Tawanda stressed the need for any biofortified crop to also be a cash crop. Essentially, for a cultural adoption of something like the orange flesh sweet potato to be sustainable, farmers must be able to both eat the crop and make money from it. After all, these farmers still need to send their kids to school, and you can’t pay for school with vitamin A.
Tawanda mentioned a great advantage of biofortification of crops is that they are “pro-poor.” The foods targeted to carry additional key nutrients are staples – potatoes, maize, rice, etc. – crops that the poorest communities eat every day. In comparison with other nutritional strategies, like supplementation via capsules, encouraging the adoption of biofortified crops has much larger coverage and much more robust sustainability. Because the farmers have incentive to sell the crops, they act as their own distribution network. Many governments in Sub Saharan Africa don’t have the money to hold up supplementation programs, so fitting the delivery of nutrition within the existing community network is far more effective.
Additionally, the sweet potato is a versatile staple crop that finds its way on to the plate in many forms. In parts of Africa, a puree made from the tuber is prized by bakers as a wheat substitute in bread and cookies (naturally, we asked Tawanda to send a recipe after his presentation), and other producers are making chips out of the biofortified potatoes. In fact, a number of those chips end up sold in Europe. By substituting sweet potato puree for wheat flour, bakers can make products that have a lower glycemic index and less sugar, so the improvements on nutrition aren’t just from the additional micronutrients. Furthermore, use of sweet potato puree has reduced wheat imports by 45% in some countries, proving that these crops can fortify both nutrition and economies.
This entire value chain – from education and dissemination to the poorest farmers to local markets to internationally traded value-added products – is the raison d’être for the orange-flesh sweet potato. Because it is used in so many ways, both culinarily and economically, it has a pretty strong foothold in terms of sustainability.
In fact, as we asked more about the uses of sweet potato, Tawanda revealed that the greens of the plant are also consumed. Although not the target of biofortification, the greens are another food source. Different groups of people tend to prize different traits in the leaves – some prefer a short, thick leaf, while others find the thinnest leaves tasty. Since the program serves a huge swath of Africa, it is important for breeders to consider these aspects of desirability in both the creation and the distribution of the new varietals. While the climactic needs of different growing regions are obvious – Tawanda pointed out that areas with high rainfall tend to pose a threat to the vines from mold – the societal needs are just as critical if you want a plant to really take root.
Despite all the research, trials, and planning that goes in to getting the new crop ready for distribution, biofortification isn’t a panacea. First of all, although the IPC’s team has achieved the same yield from their new sweet potatoes under experimental conditions, those high yields are not necessarily achieved in the field. Sweet potatoes are particularly susceptible to weevils, and although some groups are using transgenic Bt varietals to address pest problems in other crops, research of this option for sweet potatoes is still nascent. Even among those farms that flourish with the new potato, the vitamin A provided by a normal daily consumption of sweet potato is not enough to meet the total requirements. Tawanda was careful to note that they promote this new source of vitamin A as part of an otherwise healthy diet.
What I gathered from all of this was that biofortification is a varied approach, among many other equally varied approached to improving nutrition. Even disregarding the sticky issue of using genetic modification to improve nutrition, biofortified crops have some drawbacks. However, what impresses me most about this program’s approach is that they seem to have a great understanding of the way that orange flesh sweet potatoes can fit in to the system-wide value chain. It strikes me not quite as a bottom-up approach, but certainly a far cry from the top-down approaches to improving nutrition that have come from governments and other groups.
While I imagine that biofortificaiton has a lot of space to expand in terms of improving nutrition the world over, I wonder what its limitations will prove to be? Tawanda already told us that a single improved crop isn’t expected to cure an entire nutrient deficiency, but could a combination of such crops ever stamp out vitamin A deficiency? Are there other approaches that must also come in to play in order to create a sustainable, independent food system in these areas? If so, what are they, and where will they come from? So far, many governmental and NGO attempts to solve nutritional problems have petered out in to failure, at least in terms of sustainability. As Tawanda asked us, what can a research organization do to convince the government to do what is necessary?