May 3, 2018 | By Cathy Watson

Guest Commentary - Indigenous Trees and Crops Hold Keys to Nutrition in Africa

By Cathy Watson, chief of program development, World Agroforestry Centre (ICRAF), one of the 15 members of the CGIAR, a global partnership for a food-secure future.

Indigenous fruits of Balinites and Ziziphus and the pods of tamarind for sale in a market in Shire, Northern Ethiopia  (ICRAFCWatson)

In 2011, a professor at Harvard caused a stir when he analyzed the heights of women in 54 low-to-middle income countries and found it had decreased in 14 countries, all of them in Africa. This was shocking.

Adult height is a measure of standard of living, biological well-being and life expectancy, and a reliable indicator of childhood nutrition, disease, and poverty. Yet the study of 364,538 women aged 24 to 49 established that those born in the last two decades in Rwanda, Zambia, Comoros, Madagascar, the Democratic Republic of Congo, Mozambique, Nigeria, Chad, Namibia, Benin, Liberia, Mali, Niger, and Malawi were on average shorter than their mothers or grandmothers born after World War II.

“It’s a sobering picture,” Professor S.V. Subramanian told the New York Times, which ran the story on its front page. Worse still, he said, it was happening amid an overall global increase in height. In 19 of the 54 countries he had analyzed, largely the middle-income ones, women were taller than their grandmothers. And a plethora of other studies showed a global height increase in men too.

I wrote up the study for papers in East Africa. When I interviewed Subramanian, he said that this was not the first time that heights had dipped. He cited the Dutch famine in 1944-45 when the population subsisted on tulip bulbs and beechnuts. But never, he said, had such a widespread long-term decline been seen. He needed to understand one thing though. Only in Uganda are the poorest people the tallest. How could that be? There I could help. That’s the population in the north, I told him. They are emerging from war. But even before it, they were historically poorer than the rest of the country. Despite that, their diet is exceptionally rich and diverse.

In NW Uganda a refugee from South Sudan collects Balinites leaves for a stew. (ICRAFCOkia)

I described daily bowls of one or another of a multitude of indigenous vegetables, always swimming in sesame and peanut sauce and drizzled with the oil of the shea butter tree. Sometimes meals include bowls of smoked fish or meat, which is also “pasted” with sesame and peanuts. The staple, I concluded, is usually millet, its purple color a sign of a high content of iron. Later, research confirmed this impression of a diet of abundant products, many of them nutrient-dense. Farms are indeed exceptionally diverse in northern Uganda, with well over a dozen food crops not unusual. Culinary heritage and traditional farming had emerged intact from war. This story of the height of Uganda’s poorest people and the diversity of their farms is testimony to the power of indigenous crops to trump poverty.  

At the World Agroforestry Centre, we take indigenous species seriously. We believe that a greater focus on them can provide many of the micronutrients needed to address Africa’s pervasive in utero and childhood malnutrition that leads to the tragically shorter women that Subramanian found – and some of the calories as well.

One particularly compelling example is Balinites aegyptiaca or desert date. Every population group living in the almost 5000-mile band where it grows -- from Ethiopia to Senegal -- treasures its fruit, collecting it from the wild or trees on their land or buying it. Dinka pastoralists stock it in granaries. Per gram, the tangy pulp has twice the Vitamin C of an orange.

And that’s not all. The leaves are a dry season vegetable, rich in iron and protein. They are definitively not a famine food, as tree leaves are often characterized to be, but instead part of a nutritious, delicious, culturally-treasured fare. Finally, the kernels hold an oil that is high in omegas. Women in many areas extract it to cook with, sometimes feeding the crushed seed to livestock or frying them as a crunchy snack.

We are raising Balinites seedlings in a refugee settlement in northwest Uganda, encouraging its natural regeneration, and arguing that it be spared as firewood for – paradoxically – the feeding centers.

We have found that it is just one of over a dozen tree species there that provide nutrition to the vulnerable refugee and host population. Others are tamarind, figs of various sorts, shea butter trees, and dryland trees such as Ziziphus mauritania, which has a fruit that tastes like apricot, and Vitex doniana, the fruit of which resembles a black plum.

In a further burst of nature’s generosity, many of these tree species also contribute to food security by fixing nitrogen, increasing soil carbon, improving the soil biota, sustaining pollinators, maintaining soil moisture, and regulating rainwater, thereby improving yields of the crops that grow around them.  

We work on these trees under the African Orphan Crop Consortium (AOCC).  Led by the African Union and supported by many groups, including Mars, Illumina, and Google, AOCC is developing new generation genomic tools to make 101 orphan crops – about half of them trees - even more nutritious, climate smart, and productive than they already are.

Additionally, we host the trainings of the African Plant Breeding Academy (APBA). Led by UC Davis, it strengthens plant breeders from across the continent to unlock the potential of these trees and annuals, such as the African yam bean, which has both tubers and beans, and the fluted pumpkin, the leaves and seeds of which make a staggeringly nutritious sauce.

AOCC and APBA are rare beams of light shining on these crops, which have been profoundly neglected by donors, governments, aid agencies, and conventional plant improvement schemes. The last have long focused on a perilously narrow range of staples, including rice, wheat and maize.

Yet traditional crops and “food” trees could help prevent stunting, giving women greater wellbeing.

Africa’s biodiversity gives rise to diets that, at their best and most complete, as in northern Uganda, are among the world’s healthiest. Nine out of the world’s ten healthiest diets occur in Africa with people in Mali, Chad, Senegal and Sierra Leone enjoying healthier diets than their counterparts in the United States, the United Kingdom, Japan or Canada, according to The Lancet’s definitive report.

It is a race against time. Africa’s biodiversity is under threat, 65 percent of its land is  degraded, populations are growing, and trees are pouring into cities in the form of charcoal, with a consequent loss of nutrition as well as of the ecosystem services that support life.

To push back malnutrition, it is important to make staples more productive and fortify them. But a focus on this to the exclusion of other approaches could have dire costs, the implications of which are starting to be seen. These include the plowing up of nutrition-providing trees as large fields are created, the squeezing out of wild and on farm biodiversity, and a dangerous simplification of diets, when dietary diversity is a determinant of diet quality, especially micronutrient intake.

For sustainable food systems and health, the FAO recommends diversification of crops including underutilized traditional crops. Let us give tree-based diets and indigenous species their place in our programming, policies, research, and targets for nutrition and food security.


The Global Food and Agriculture Program aims to inform the development of US policy on global agricultural development and food security by raising awareness and providing resources, information, and policy analysis to the US Administration, Congress, and interested experts and organizations.

The Global Food and Agriculture Program is housed within the Chicago Council on Global Affairs, an independent, nonpartisan organization that provides insight – and influences the public discourse – on critical global issues. The Council on Global Affairs convenes leading global voices and conducts independent research to bring clarity and offer solutions to challenges and opportunities across the globe. The Council is committed to engaging the public and raising global awareness of issues that transcend borders and transform how people, business, and governments engage the world.

Support for the Global Food and Agriculture Program is generously provided by the Bill & Melinda Gates Foundation.


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