Assessing Nutritional Diversity of Cropping Systems in African Villages

Abstract

BackgroundIn Sub-Saharan Africa, 40% of children under five years in age are chronically undernourished. As new investments and attention galvanize action on African agriculture to reduce hunger, there is an urgent need for metrics that monitor agricultural progress beyond calories produced per capita and address nutritional diversity essential for human health. In this study we demonstrate how an ecological tool, functional diversity (FD), has potential to address this need and provide new insights on nutritional diversity of cropping systems in rural Africa.Methods and FindingsData on edible plant species diversity, food security and diet diversity were collected for 170 farms in three rural settings in Sub-Saharan Africa. Nutritional FD metrics were calculated based on farm species composition and species nutritional composition. Iron and vitamin A deficiency were determined from blood samples of 90 adult women. Nutritional FD metrics summarized the diversity of nutrients provided by the farm and showed variability between farms and villages. Regression of nutritional FD against species richness and expected FD enabled identification of key species that add nutrient diversity to the system and assessed the degree of redundancy for nutrient traits. Nutritional FD analysis demonstrated that depending on the original composition of species on farm or village, adding or removing individual species can have radically different outcomes for nutritional diversity. While correlations between nutritional FD, food and nutrition indicators were not significant at household level, associations between these variables were observed at village level.ConclusionThis study provides novel metrics to address nutritional diversity in farming systems and examples of how these metrics can help guide agricultural interventions towards adequate nutrient diversity. New hypotheses on the link between agro-diversity, food security and human nutrition are generated and strategies for future research are suggested calling for integration of agriculture, ecology, nutrition, and socio-economics.

Improving diets with wild and cultivated biodiversity from across the landscape

“…Two further studies reported positive relationships between crop diversity and intake of nutritious foods such as fruits and vegetables (Herforth 2010;Jones et al 2014). Remans et al (2011) reported an association between crop diversity and dietary diversity at the village level, but not at the household level.…”

“…Of the studies which measured dietary diversity at the household or individual level: six reported a positive association with crop diversity (Ekesa et al 2008;Herforth 2010;Powell 2012;Jones et al 2012Jones et al , 2014Oyarzun et al 2013), one reported a positive association in one community but not another (Dewey 1981), and two reported no association (Torheim et al 2004;Remans et al 2011). Keding et al (2012) showed an association between diversity of vegetables cultivated and dietary diversity (number of food groups).…”

The Contribution of Forests and Trees to Sustainable Diets

“…The roles of micronutrients in health and well-being and the synergies with the physiological functions of nutrients have been recognized [125,126]. Nutrition interventions should thus focus on improving overall diet quality.…”

Application of the Nutrition Functional Diversity indicator to assess food system contributions to dietary diversity and sustainable diets of Malawian households

“…A third advantage is that using a trait-based approach permits a methodological link between environmental and nutritional objectives, so that either agro-ecological traits, such as biodiversity of cropping systems, or nutritional traits, such as nutrient content of crops, could be studied using an analogous functional diversity metric in the same farm/household system. While DeClerck et al (25) and Remans et al (26) showed how NFD can be applied to measure the nutritional diversity of different cropping systems, these studies were limited in scope to thirty farms in Kenya and 170 farming households in three East African countries, respectively. Neither study applied the NFD score to foods consumed or examined the role of geography and markets in providing nutritional diversity.…”