Mineral malnutrition due to environmental and cultural factors is widespread in sub-Saharan Africa (SSA). A multi-national research consortia led by the University of Nottingham (UoN) undertook a pump priming project to explore if Ecosystem Services could provide an effective conceptual framework to link biogeochemical cycles of dietary minerals and poverty. The project initially focussed on iodine, selenium and zinc in Malawi and Zambia. Through data integration, feasibility studies, networking and capacity building we addressed three target themes: Biogeochemistry, Nutrition, and Economics.
Biogeochemistry: we developed a new GIS (ArcGIS) framework linking soil and land-use data has been submitted for open-access peer review publication. New geochemical data for soils and vegetation were incorporated from an aligned project (UoN) and other spatial data (e.g. DFID FarmLime, BGS). Through integration of soil types in GIS, we have found that the population Se intake from maize is typically 6-7 µg Se per day, which represents ~10% of the dietary requirements for Se. Since maize provides the majority of dietary energy to the rural poor of SSA, this study revealed for the first time that chronic Se deficiency is endemic for the majority of the population and is largely influenced by input from soil.
Major knowledge gaps still exist. Further sampling, capacity building and data integration activities were therefore planned at a workshop in Lilongwe in September 2010 with multiple government departments and regional academics for future funding application.
Nutrition: a feasibility study was completed to study the spatial variation in I, Se and Zn dietary intake and status in Malawi as a case study. The National Health Sciences Research Committee of the Malawi Ministry of health granted ethical approval for dietary and biomarker surveys and intake analyses across several villages. Importantly, sensitisation visits to the villages and farmers was undertaken by extension services, Ministry of Health and PI's. Data showing strong geochemical control of intake and status, and these will be submitted for publication later in 2011.
Economics: a novel Ecosystem Services framework was developed based on: modelling soil-to-diet relationship using mineral / dietary-energy units; food choices and land-use; quantifying relationship between disease burdens and poverty at population levels. Economic analyses were formalised using World Health Organisation Disability Adjusted Life Years (DALYS), which incorporated a willingness to pay for intervention. Such analyses provide a useful policy tool at national and regional scales.
For example: despite limited data, a pilot analysis estimated that 3,955 healthy life years (DALYS) per 1m population per year are lost each year in Malawi due to Zn deficiency alone, mostly due to infant mortality. This represents an economic loss to Malawi of >1% GDP per year. Economic analyses for I, Se and other elements requires more data.
This work was funded via the Ecosystem Service Poverty Alleviation programme by UK DFID-NERC.
Project partners included: British Geological Survey, University of East Anglia, Genius Consultancy, University of Sabanci, University of Adelaide, University of Otago, University of Malawi, University of Zambia, Ministry of Agriculture & Health (Malawi).
Dr Martin Broadley, University of Nottingham. email@example.com