Impacts of WASH on acute malnutrition: from available scientific evidence to informed action

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Research snapshot¹

Many of the 4.5 billion people who do not have access to improved sanitation or the 2.1 billion people who do not have access to safe drinking water sources are the same populations with high levels of acute malnutrition (AM). The hypothesised causal pathways between poor Washing, sanitation and hygiene (WASH) and child malnutrition consist namely of diarrhoea, environmental enteric dysfunction and helminth infections (worms) and, indirectly, the ability of families to provide safe and clean living environments, the time it takes to do so and the time it takes to adequately care for children in such environments. The aim of this review was to identify and evaluate the strength of the available evidence related to WASH and AM through a search of literature published between 2000 and 2017.

After inclusion and exclusion criteria were applied, 24 articles were included in the final analysis. Very little research has been conducted on the effect of WASH interventions on the treatment of AM, although evidence is building on the additional benefits of providing water treatment supplies and counselling for improved water quality alongside treatment. While additional trials are needed, treatment programmes may consider the feasibility and cost of adding a water quality component to the current standard of care, with a focus on the continuation of such behaviours after discharge to help reduce relapse.

Many low-quality studies have been conducted that indicate associations between WASH-related indicators and child AM but very few high-quality intervention trials have been conducted that demonstrate significant impact on preventing malnutrition. The WASH sector includes a wide variety of diverse interventions. Extensive context analysis may be necessary before designing a WASH intervention to best match the intervention with the specific needs of the target population. Environmental testing may be helpful to determine what harmful pathogens are particularly present in the context and which interventions are best suited to stop transmission. It may also be possible that environments are so contaminated that one or even the combination of a few interventions aimed at individual or household level does not reduce the amount of exposure to harmful pathogens to realise an impact on AM and that community-level interventions may show more promise. 

The author concludes that the current state of the evidence regarding associations between WASH and AM outcomes is very weak. Although hypothesised causal pathways are supported by strong logic, they have yet to be consistently proven through rigorous studies. High-quality, rigorous intervention studies are needed to prove or disprove the links between WASH and child AM to guide decision-making.

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