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Modelling underutilized foods into diets that boost health and food security

Kenyan mother feeding her child. Credit: Bioversity International/S.Collins

Scientists working with communities in Kenya have demonstrated an innovative approach to boosting the nutritional quality of local diets while also reducing their cost.

Scientists working with communities in Kenya have demonstrated an innovative approach to boosting the nutritional quality of local diets while also reducing their cost.

Their work capitalized on the opportunities presented by a seemingly unlikely situation: high rates of malnourishment in an area with high agricultural biodiversity. This incongruity results from shifting dietary norms and influences over a number of years.

The recently published open access paper Assessing the potential of wild foods to reduce the cost of a nutritionally adequate diet explains how the research made use not only of up-to-date modelling and assessment techniques but also of ethnobiology and the traditional knowledge held within communities. This unusual combination enabled the scientists to recommend dietary improvements that, uniquely, include wild or under-used local plant foods. The outcome of their work to date is two-fold: a set of guidelines for an optimized, cost-minimized diet relevant to the health needs of the community and the local ecology, and a promising new method for producing equivalent recommendations for other regions.

The scientists from Bioversity International, in collaboration with Save the Children UK, focused on young children and their mothers in the eastern region of Kenya's Baringo District in Rift Valley Province. This is an ecologically diverse area that features a wide variety of edible, wild and cultivated plant and animal species. It is also an area with demonstrably high levels of malnutrition: 36% of children in the province suffer from stunted development attributed to nutritional deficiencies.

Focusing on pregnant and lactating mothers and children up to two years of age, the scientists set out to improve dietary quality while simultaneously reducing food costs, and explore the potential of under-used biodiversity for achieving this. The team already had a modelling tool designed to meet similar challenges at their disposal, developed by Save the Children.

The 'Cost of Diet' tool employs a numerical method called linear programming. It runs within Excel and incorporates internationally agreed databases that provide the nutrient contents of different foods and recommended nutrient intakes. For application to a specific area, users add a list of locally available foods and prices. The tool then models the best available diet at the lowest cost by optimising foods, portion sizes, frequency of consumption and prices while meeting requirements for nutrients and energy – and other issues such as palatability and cultural acceptability.

When the 'Cost of Diet' tool modelled the best diets for women and children based on typically sourced foods, the results were lacking in several essential micronutrients. Infants at certain stages and times of year were deficient in vitamin B6, calcium, iron and zinc. Iron was deficient for all age groups during the dry season. Not only were these diets incomplete, they were also considered unaffordable for poorer households.

Seeking options to remedy this, the researchers interviewed local people to learn about traditional, alternative food sources. From these discussions they compiled an ethnobiological inventory of wild and underutilized local edible species and selected the five most promising (a wild leafy vegetable and four wild fruits) for additional inclusion in the tool.

When they ran the model again, the results were clear: adding the five wild foods resulted in significant reductions in costs. In the dry season, the optimum diet for children aged 12 to 24 months cost up to 64% less. The wild foods also boosted the nutritional quality of the diets. In particular, they enabled the recommended intakes of iron for women and children between 12 and 24 months to be met in both wet and dry seasons. One of the wild foods stood out: Berchemia discolor (a date-like fruit, also called bird plum or wild almond) contributed most to nutritional improvements and cost reductions. However adding in the wild foods did not fully resolve iron, zinc, vitamin B6 or calcium deficiencies for infants throughout the year. In addition, the opportunity costs involved in foraging for and preparing these foods were not taken into account.

While the research has not offered a panacea for these particular communities, it has clearly pointed to alternative, promising avenues to explore in cases where dietary deficiencies are identified.

Dr Céline Termote, lead author on the paper and researcher at Bioversity International said: "This shows the benefits of looking at the agricultural-nutritional linkages before resorting to outside interventions."

Ultimately, the scientists would like to see the study undertaken in different settings and with a refined analysis tool that includes more detail on food species availability and composition. Pilot projects to increase the harvest of wild and underutilized foods should also, they suggest, be developed.

Dr Termote explained that for now, the next priority will be to discuss the options available for future study in Western Kenya, working closely with the communities there. "If funding allows, we hope to follow up with a programme of monitoring and evaluation."

Download the paper - Assessing the potential of wild foods to reduce the cost of a nutritionally adequate diet: An example from eastern Baringo District, Kenya," Termote et al, 2014

For more information, contact Céline Termote

This work was carried out in collaboration with Save the Children UK and the National Museums of Kenya, and supported by the Bill & Melinda Gates Foundation and the CGIAR Research Program on Agriculture for Nutrition and Health.