Category: Nutrition

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Detoxifying cassava

Strategies that minimize one risk…may augment another risk… Peasant farmers are perfectly conversant with such linkages. The neglect of peasant agriculture by both donors and governments is among the deeper causes of current crises, along with the increasing inequality that deprives them of secure tenure to land and other resources, reducing benefits they can expect to receive from stewardship of these resources.

That comes towards the end of a lengthy, information-dense and closely argued paper on cassava’s domestication, evolution and chemical ecology by Doyle MacKey and others. ((McKey, D., Cavagnaro, T., Cliff, J., & Gleadow, R. (2010). Chemical ecology in coupled human and natural systems: people, manioc, multitrophic interactions and global change Chemoecology, 20 (2), 109-133 DOI: 10.1007/s00049-010-0047-1)) Coincidentally — or perhaps not — McKey also has a paper out just now on the evolutionary ecology of vegetatively propagated crops in general. ((McKey, D., Elias, M., Pujol, B., & Duputié, A. (2010). The evolutionary ecology of clonally propagated domesticated plants New Phytologist, 186 (2), 318-332 DOI: 10.1111/j.1469-8137.2010.03210.x)) But that’s something for a future post, perhaps. Back to cassava.

Well, as I say, there’s a lot of stuff in the paper, but let me focus on a just a couple of things here. Some cassava varieties are high in poisonous cyanogens, requiring laborious and time-consuming processing for detoxification, which is almost exclusively done by women and, according to at least one anthropologist, serves to control them, “by limiting their freedom of action, in male-dominated societies.” So let’s replace those high-cyanogen, “bitter” varieties with low-cyanogen, “sweet” varieties, right?

Well, not so fast. ‘‘Interestingly enough, the women that are the custodians of this crop do not perceive the processing or the toxin to be a problem.’’ Bitter manioc is in fact better for food security for at least three reasons: it is protected against pests; immediate processing deters thieving; and the value added through processing reduces the social obligation to share. Overall, therefore, “processing bitter manioc is viewed as a useful and valorizing activity.”

But there are regular epidemics still in some parts of Africa of the paralytic disease konzo, which is “associated with several weeks of almost exclusive consumption of insufficiently processed bitter cassava.” Surely low-cyanogen varieties would be welcome there?

Again, the authors are dubious. They point out that agronomic practices, in particular careful nutrient management, together with adequate processing and a reasonably protein-rich diet are perfectly sufficient to manage the toxicity problem, and in fact normally do so. It is mainly when socioeconomic stability breaks down that konzo erupts. As they trenchantly put it: “This crop needs peace.” And reasonable rainfall. Drought stress tends to increase cyanogen levels. Plus, “[a]s they face food shortage, people may then take short cuts in processing bitter manioc.” In both cases, new, faster, more efficient detoxification methods will have a bigger impact than sweet varieties, with their greater susceptibility to pests.

In general, cassava is expected to be comparatively little affected by climate change, and is being promoted in some quarters as a “food for the future.” Fair enough, say the authors, but this

…will need to be accompanied by the necessary education for processing, as planting less bitter cultivars appears not to be a solution. Farmers have good reasons for preferring bitter varieties.

Indeed they do. So let me end with another heady quote, again from the concluding section of the paper, a little further on from the quote I started with.

We must have the humility and the broad vision to accept that our science can provide essential pieces, but only pieces, of viable solutions. ‘‘Modern’’ science can work in creative ways with folk knowledge. But no technological fix is a ‘‘magic bullet’’.

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Sea buckthorn becoming a success in a land with no sea

The name of the game in Mongolian agriculture is diversification. And one of the things researchers at PSARTI, the Plant Science Research and Training Institute in Darkhan, and others are looking at is a shrubby berry called sea buckthorn (Hippophae rhamnoides) with some interesting nutritional properties. They have put together a small germplasm collection of local and introduced material and are doing agronomic trials of various kinds, trying to find the best varieties for different purposes. In fact, the plant has a pretty long and rich history in Mongolia:

It is said that Genghis Khan, the Mongol conqueror, who established one of the largest empires from China to Eastern Europe in the 13th century, relied on three treasures: well organized armies, strict discipline and Seabuckthorn. Seabuckthorn berries and seed oil made Genghis Khan’s soldiers stronger than his enemies.

There are already some products on the market. Like this delicious icecream, called Ice Doctor.

The natural history museum in downtown Ulaanbaatar has a display featuring a number of locally-made products — a couple of different oils and “globules” — along with a somewhat threadbare diorama.

I guess commercialization still has some way to go, but a start has been made. Another wild species with some commercial potential may be strawberries.

Wild Allium of various kinds is also sold in the market.

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Genebanks shenebanks

Why bother building and maintaining huge robotic genebanks, I hear you ask? They’ll just take over the world and we’ll end up having to deal with the Terminator in a few years’ time, no? Well, as it happens there are two pieces today on the Worldwatch Institute’s blog which explain the reasons. Yassir Islam of HarvestPlus says that researchers are “scour[ing] seed banks to find seeds that contain the desired nutrients and then breed these into popular varieties using conventional methods.” And Cary Fowler of the Global Crop Diversity Trust turns to Ug99:

Where do you suppose scientists are looking for a way to deal with the disease? Just as Professor Borlaug did, they are screening hundreds of varieties of wheat to find one that shows resistance to the disease. Where would we turn if we did not have that diversity available in genebanks?

What more do you need? Oh yeah:

The UN Food and Agriculture Organization (FAO) estimates that a third of all genetic resources for food and agriculture have already been lost in the last 100 years.

Right. But at least it’s an improvement on 75%.

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Nibbles: FAOSTAT, Drought, Seeds, Helianthus, Coffee trade, CePaCT, Figs, Old rice and new pigeonpea, Navajo tea, Cattle diversity, Diabetes, Art, Aurochs, Cocks

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From fiasco to food systems

A contribution from Jessica Fanzo of Bioversity International. Many thanks, Jess!

As of 2010, one billion people are hungry, and 129 and 195 million children under five years of age are underweight and stunted respectively, with 90% of these children living in just 36 countries. Vitamin A and zinc deficiency alone contribute to over half a million child deaths annually. How could things have gone so wrong? Why is hunger and poor nutrition increasing or at least stagnating in much of the developing world?

Much of this falls on the nutrition and development community themselves. Although the prevention and treatment interventions highly endorsed in the 2008 Lancet series on maternal and child undernutrition provided some consensus among the global nutrition community, not all are comfortable with the current interventions being put forth to scale, which are predominantly health- and clinic-based interventions. To add more complications, the “how” to implement interventions from country to country in the developing world remains elusive. But then the international nutrition community has always been contentious.

The latest debate is coming from Michael Latham’s recent paper in World Nutrition, which is rebuking an often regarded “life saving” and cost effective intervention of giving children ages 6 to 59 months of age two high doses of vitamin A. Pioneering work by colleagues such as Professors Alfred Sommer and Keith West demonstrated very effectively that vitamin A can save children’s lives and prevent vitamin A caused blindness. And it certainly does, particularly in places where vitamin A deficiency has wreaked havoc on the lives of children. And we know that there are pockets where vitamin A deficiency still does.

Latham reported that what was thought of as a stop gap or short-term approach in preventing vitamin A deficiency, became THE only recommended approach to treat such deficiencies. He contests the evidence that the supplements reduce child morbidity: they not only have little effect on mortality, but can have adverse effects on respiratory infections, he says. Latham argued that the International Vitamin A Consultative Group and UNICEF pushed for the “magic bullet” capsule approach, in collaboration with industry, with little regard for other approaches, including plant-based foods.

So the debate continues. What PREVENTATIVE approaches should be undertaken? Prevention and treatment-based interventions, such as vitamin A supplementation, form a necessary and important dimension of addressing immediate needs and undernutrition. But more durable reductions in hunger must be accompanied by strategies that enhance food and livelihood security, including food production-based approaches aimed to enhance food availability and diet quality through local production and agricultural biodiversity.

There are food-focused interventions that can be integrated into the agriculture investments (largely staple crop food production) that could improve diet diversity and quality of diets rich in vitamin A sources, directly impacting the nutritional status of children. Promotion and usage of diverse homegardens and intercropping of plant foods rich in carotene, such as leafy greens and fruits such as mango, papaya, bananas, and pumpkin, along with plant oils, can provide rich sources of vitamin A for family diets, especially for complementary foods for young children. Livestock and small animal rearing can provide rich sources of vitamin A even if consumed a few times during the week. Introduction of nutrient-rich foods such as orange-fleshed sweet potato have been shown to increase vitamin A intake and serum retinol concentrations in young children in east Africa.

However, there is more than one way to skin a mango. The food-focused interventions are as essential as the vitamin A supplements as stop gaps in areas with documented vitamin A deficiency. But we need to go further. Recent calls for greater attention to hunger and undernutrition highlight the importance of integrating technical, well-coordinated interventions with broader strategies that address underlying causes of food insecurity – incorporating perspectives from agriculture, health, water and sanitation, infrastructure, gender and education. We need to think beyond “interventions” and more about systems approaches – in particular, food systems. How can food be better grown to improve the quantity and quality of the diet and of livelihoods. Food systems involve not only the land itself, but also water, natural resources, the ecosystem as a whole, and of course food, but all tethered to together with gender equity, better education, and legal reform and land tenure. Long-term investments in ensuring food systems are protected, conserved, rebuilt or promoted will be critically important to making real progress in preventing vitamin A deficiency, undernutrition and hunger, and ultimately the big culprit of them all, poverty.