title: Assessing nutritional diversity of cropping systems in African villages.
abstract: BACKGROUND
  In 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.
  
  
  RESULTS
  Data 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.
  
  
  CONCLUSIONS
  This 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.
authors.affiliation: The Earth Institute at Columbia University, New York, New York, United States of America. rremans@ei.columbia.edu
authors.forename: Roseline
authors.initials: R
authors.lastname: Remans
authors.forename: Dan F B
authors.initials: DF
authors.lastname: Flynn
authors.forename: Fabrice
authors.initials: F
authors.lastname: DeClerck
authors.forename: Willy
authors.initials: W
authors.lastname: Diru
authors.forename: Jessica
authors.initials: J
authors.lastname: Fanzo
authors.forename: Kaitlyn
authors.initials: K
authors.lastname: Gaynor
authors.forename: Isabel
authors.initials: I
authors.lastname: Lambrecht
authors.forename: Joseph
authors.initials: J
authors.lastname: Mudiope
authors.forename: Patrick K
authors.initials: PK
authors.lastname: Mutuo
authors.forename: Phelire
authors.initials: P
authors.lastname: Nkhoma
authors.forename: David
authors.initials: D
authors.lastname: Siriri
authors.forename: Clare
authors.initials: C
authors.lastname: Sullivan
authors.forename: Cheryl A
authors.initials: CA
authors.lastname: Palm
mesh_terms: D000328:Adult; D017954:Africa South of the Sahara / Q000453:epidemiology; D018798:Anemia, Iron-Deficiency / Q000453:epidemiology; D018556:Crops, Agricultural; D005260:Female; D006801:Humans; D009753:Nutritive Value; D012424:Rural Population; D014802:Vitamin A Deficiency / Q000453:epidemiology