Assessing nutritional diversity of cropping systems in African villages.

Roseline Remans,Roseline Remans,Roseline Remans,Jessica Fanzo,David Siriri,Patrick K Mutuo,Cheryl A Palm,David Siriri,Kaitlyn Gaynor,Kaitlyn Gaynor,David Siriri,Clare Sullivan,Clare Sullivan,Fabrice Declerck,Fabrice Declerck,Fabrice Declerck,Phelire Nkhoma,Willy Diru,Isabel Lambrecht,Dan F B Flynn,Joseph Mudiope,Cheryl A Palm

doi:10.1371/journal.pone.0021235

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.

Highlights

While great strides in reducing hunger through increases in agricultural productivity have been made worldwide, more than 900 million people are undernourished [1], over 2 billion people are afflicted by one or more micronutrient deficiencies [2] and over 1 billion adults are overweight [3]
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
As new investments and attention galvanize much-needed action on African agriculture, a vigorous debate is required to ensure that agricultural progress is evaluated based on metrics that go beyond economic cost/benefit ratios and calories per person and that can address the complexity of nutritional diversity required for human health

Summary

Introduction

While great strides in reducing hunger through increases in agricultural productivity have been made worldwide, more than 900 million people are undernourished [1], over 2 billion people are afflicted by one or more micronutrient deficiencies [2] and over 1 billion adults are overweight [3]. Success of agricultural systems has historically been evaluated primarily on metrics of crop yields, economic output and cost-benefit ratios [8]. These metrics do not reflect the diversity of nutrients provided by the system that is critical for human health. 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

Results

Discussion

Conclusion