Momentum builds for role of trees in health and nutrition
There is growing recognition that trees can help to sustain human health across the globe, but more research and attention is still needed to exploit the full potential of food-producing trees in diversifying diets and supplying micronutrients.
Recently, the World Agroforestry Centre published information on its fruit tree portfolio approach, outlining how farmers in Machakos, Kenya can achieve a year-round supply of nutritious fruits through planting just 10 suitable tree species. There are plans to expand the fruit tree portfolio approach to several other locations in Africa to diversify diets year-round and improve health.
In related work, scientists from the Centre contributed to a groundbreaking publication, released earlier in 2015, on the human health benefits that come from conserving and sustainably using biodiversity.
Connecting Global Priorities: Biodiversity and Human Health is a joint publication by the Secretariat of the Convention on Biological Diversity (SCBD) and the World Health Organization (WHO) which outlines how elements of biodiversity and the products and services derived from it, such as water and air quality as well as nutrition and medicines for humans and livestock, positively benefit our health.
Chapter 6 on ‘Biodiversity and Nutrition’ was co-authored by Centre scientists, Stepha McMullin, Katja Kehlenbeck and Ramni Jamnadass together with colleagues from the Center for International Forestry Research (CIFOR) and Bioversity International. It looks specifically at how a diversity of species, varieties and breeds, as well as wild foods (such as indigenous tree species) and medicinal sources underpins dietary diversity, good nutrition and health.
“Human health is intertwined with biodiversity,” says Stepha McMullin. “We can’t isolate the health of humans from the health of ecosystems.”
“If our ecosystems become degraded or we lose the diversity of foods upon which we depend, then we will be presented with a major public health challenge.”
Wild food such as leafy vegetables, mushrooms, nuts, indigenous fruits, insects and bushmeat make a major contribution to dietary diversity and nutrition across the world, especially in poor countries.
“There are indigenous communities that continue to use 200 or more species in their diets, but the global trend is towards dietary simplification focusing on just a few species,” explains McMullin. “This narrowing of diets to focus in on staples has had a negative impact on human food security, nutritional balance and health.”
Trees are among the wild foods which are largely being neglected despite the fact that they provide direct and indirect benefits for human nutrition, including supplying fruits that have a high nutrient content, fuel wood that can be used to cook foods as well as possibilities for income generation and greater environmental stability and resilience of farming systems.
The potential for many wild food tree species to contribute to better diets and income generation across the globe is relatively untapped. McMullin suggests this is mainly due to the fact that there has been little research on their nutritive and economic value, combined with a general lack of recognition among development programs and donors about the contribution that biodiversity makes to food security, nutrition and health.
One species with high potential is the African Baobab (Adansonia digitata), the subject of ongoing research by the World Agroforestry Centre and partners. The fruit of this distinctive tree, which commonly occurs in African savannas, contains far higher amounts of Vitamin C, calcium and iron than more common tropical fruits such as mango and orange. Oil derived from the seeds can be eaten, as can the leaves which are highly nutritious.
“Baobab offers an opportunity to improve nutrition in the savannas, scrublands and semi-deserts of sub-Saharan Africa,” says Katja Kehlenbeck, adding that it is just one of hundreds of wild food trees in Africa that can contribute to food and nutritional security.
The food tree team at the World Agroforestry Centre has selected baobab as a model species for the many underutilized wild fruit tree species. As a first step towards domestication of the baobab, the team has developed a Descriptor for Baobab in collaboration with Bioversity International. Now the team is studying the morphological and genetic diversity of baobab in Kenya and analyzing the nutrient content of its pulp to identify the most valuable trees that can be used for domestication.
Grafting experiments are being undertaken to reveal the best propagation methods so that improved grafted baobab seedlings can be distributed to farmers. At the same time, the team is conducting a value chain analysis and working with colleagues from Jomo Kenyatta University of Agriculture and Technology to explore novel food products such as yoghurt from baobab pulp.
“If Kenyan farmers are linked to domestic and export markets for baobab pulp, and consumers in Kenya and elsewhere are aware of the health benefits of this ‘super fruit’, the iconic baobab tree could contribute to poverty alleviation and malnutrition in rural dryland communities,” says Kehlenbeck.
McMullin, Kehlenbeck and colleagues are hopeful that initiatives such as the fruit tree portfolio approach and the CBD-WHO publication which help to build greater momentum for research and an increased focus on the role of indigenous species in improving diets.
Download the publications:
Kehlenbeck K and McMullin S. 2015. Fruit tree portfolios for improved diets and nutrition. How to use the diversity of different fruit tree species available in Machakos county to provide better nutrition for smallholder farming families. Nairobi: World Agroforestry Centre.
Romanelli C. Cooper D. Campbell-Lendrum, D. Maiero M. Karesh W.B. Hunter D. Golden C.D. 2015. Connecting global priorities: biodiversity and human health: a state of knowledge review. World Health Organization / Secretariat of the Convention on Biological Diversity.
Kehlenbeck K. Padulosi S. and Alercia A. 2015. Descriptors for Baobab (Adansonia digitata L.). Bioversity International, Rome: Italy and World Agroforestry Centre, Nairobi: Kenya.