Agriculture and health experts must work together to tackle disease, poverty and malnutrition, says development expert Jeff Waage.
The relationship between agriculture and health may seem intuitive and simple grow more crops and people will have more food and live healthier lives. But because agriculture and health policies are rarely coordinated, the reality is far more complex.
The truth is that despite a huge increase in agricultural productivity and food availability over the past 50 years, and falling food prices, about a billion people remain chronically undernourished.
At the same time, production of cheap refined cereals, sugars and fats is contributing to urban diets that are energy dense and nutrient poor, leading to rapidly growing rates of obesity and diabetes, and associated chronic diseases. This dietary transition is now being seen in countries like China, India and Mexico.
A burden on the poor
Health problems related to agriculture are particularly acute in low and middle income countries. Governments there may face both chronic rural undernutrition and worsening urban diets a 'double burden' of diet-related disease.
Developing nations also have the greatest food safety threats from chemical and biological contamination in the food chain, such as pesticides, mycotoxins and zoonotic disease, as well as threats from wildlife and livestock, such as the Ebola virus and avian flu.
Most of the poor in these countries are farmers and farm workers, who depend on agriculture for their livelihoods, including the income needed to buy health services. Threats to agriculture become threats to health.
The reverse is also true. Diseases such as HIV/AIDS not only exacerbate malnutrition but can devastate labour, farm productivity and livelihoods. A study in Kenya has shown that the death of male household heads can slash per capita household food production by two thirds. These health and agriculture interactions create a downward spiral of declining health and resources.
Health and agriculture together
The key to tackling these problems lies in better integration of health and agricultural interventions and policy. To start, this means identifying negative interactions and working together to address them.
For example, irrigation projects that increase yields may unintentionally encourage diseases such as malaria or schistosomiasis. In Sri Lanka, intensification projects that have introduced both irrigation and pig production have created ideal conditions for Japanese encephalitis, whose mosquito vectors breed in ditches and use pigs as alternative hosts.
Involving health experts in agricultural development projects can help to foresee such threats and improve project design.
More generally, the focus of agricultural development on increasing the supply and reducing the cost of food energy that is, carbohydrates and fats has helped to imbalance human diets. Agriculture and health experts must work together to re-establish the balance by making foods with essential micronutrients cheaper and easier to access.
Barriers to integration
What stands in the way of integrating agriculture and health research for development?
In part, it is a language barrier: agriculturalists, for example, may talk of improving health in terms of food energy, while health specialists deal in disability adjusted life years (DALYs).
And most of our estimates of food consumption and dietary health from which we estimate undernutrition come from extrapolating agricultural production statistics, not from real measures of what people eat and how this affects their health.
Common metrics and methods would underpin an integrated approach. For instance, a recent study on 'golden rice' rice engineered for high vitamin A content in the Philippines, expresses the benefits of agricultural innovation in terms of DALYs, while a study in Mongolia on the zoonotic disease, brucellosis, integrates animal production and human health metrics in predicting the cost effectiveness of control.
But the most important barrier to integration is the longstanding isolation of agriculture and health, and their research and policy processes. We see these 'silos' in the UN's intergovernmental bodies, in national ministries and in universities.
A fragmented development landscape can reduce the efficiency and effectiveness of policy interventions.
Take strategies for improving basic nutrition. There are four proven ways of doing this: supplementing diets of the poor, fortifying processed foods, breeding more nutritious crops (biofortification) and encouraging greater agricultural and dietary diversity.
In principle, these methods comprise an excellent and flexible toolbox that, in the right combination, offers one of the best ways of halting malnutrition. But each method is 'owned' and promoted by different communities of health or agricultural specialists, making a joined-up approach difficult.
The solution is for researchers from both backgrounds to work better together towards common goals. The new Leverhulme Centre for Integrative Research on Agricultural and Health (LCIRAH) is a step in this direction.
It brings together academics from health, agriculture and other disciplines across the social and natural sciences to define and build agri-health research for international development. The agency is an initiative of the London International Development Centre, a University of London consortium that applies interdisciplinary approaches to complex development problems.
Besides LCIRAH, there are other hopeful signs that silos are crumbling. For example, the Consultative Group for International Agricultural Research (CGIAR) is preparing a programme for agriculture and health research.
And concepts of 'one health' and 'eco-health' which link animal systems, human health and environment are being incorporated into practical programmes in the UN and elsewhere.
Two development sectors that should never have been separated are slowly coming together again.
Professor Jeff Waage is director of the London International Development Centre and chair of the Leverhulme Centre for Integrative Research on Agriculture and Health.