The WASH & Nutrition Nexus
When we would scale up nutrition-specific interventions, research suggests that the prevalence of childhood stunting, also known as chronic undernutrition, can be reduced by 20% (1). Even though this reduction of 20% means that 33 million children will be prevented from being stunted, it also means that in 80% of the stunted cases, an exclusive focus on nutrition only is not enough.
These numbers illustrate the multicausal nature of stunting. Besides the dietary intake, there are multiple factors involved that determine the nutritional status of a child. Looking at the UNICEF conceptual framework of determinants of undernutrition (2), shown in figure 1, these different factors can be categorised into immediate, underlying and basic causes.
Figure 1: Adapted UNICEF framework on maternal and child undernutrition
Whether there is a proper balance between the number of nutrients absorbed and the number of nutrients required by the body, is determined by the immediate causes. This balance will not exist when the dietary intake is inadequate, leading to an energy deficit or a deficiency in essential micronutrients. This balance can also be thrown off when disease in the body is causing the malabsorption of nutrients (3). Diarrhoea, acute respiratory infections or parasitic infections like malaria are common diseases that negatively impact the absorption of the nutrients consumed.
Whether a household has an adequate dietary intake or whether he/she is at risk of disease, is mainly influenced by underlying factors operating on the community and household level. Household food insecurity, inadequate care and feeding practices, unhealthy household environments and inadequate health services are underlying causes. In their turn, these underlying causes are influenced by the broader social-economic context in which culture, politics, climate and gender all play a role (2).
Water, sanitation and hygiene (WASH) is a major risk factor determining whether the household environment is a healthy one to grow up in (4). Numerous studies have shown the positive impact of WASH interventions on the nutritional status of children, with the greatest effect during the first 1000 days of a child’s life (5,6). The Link NCA studies, which is a participative, mixed-method study used to identify the causes of under-nutrition in a given context, have shown the strong attributable effect of an inadequate WASH environment on the nutritional status of children (5). Why this is, can be explained by the direct and indirect links between WASH and the nutritional status.
Figure 2: Adapted Action Contre la Faim framework on nutritional status
An environment that is inadequate in water, sanitation or hygiene enables the exposure to pathogens via different faecal-oral routes. Once these pathogens are ingested directly or through foods, they can cause long-term enteric damage and complications within the intestines. The 3 most prevalent pathologies as a result of an inadequate WASH environment are intestinal worm infections, environmental enteric dysfunction (EED) and diarrhoea. Environmental enteric dysfunction is ‘the chronic infection of the small intestine caused by extended exposure to faecal pathogens’ (7). The establishment of these diseases reduces the ability of the body to properly absorb nutrients and to defend itself from disease due to a reduced immunity (8). This initiates and perpetuates the state of undernutrition. WASH interventions to reduce exposure to and ingestion of harmful bacteria can reduce the prevalence of intestinal worm infections, EED and diarrhoea and with that reduce the risk of undernutrition (4,6).
Besides directly influencing the health of a child through pathogen exposure, WASH also influences the broader social-economic environment which indirectly influences the nutritional status of a child (5). This includes the price of water, sanitation and hygiene services, the distance family members have to walk daily to fetch their water, the educational level of the families and the level of poverty they experience.
A proper WASH environment is required to prevent the chronic poverty cycle from being self-perpetuating (9). Having a low income often results in reduced access to WASH, which subsequently leads to ill health, malnutrition and disease. This state of poor health keeps children from going to school or parents from having a proper job, which in its turn leads to an economic decline and limited opportunities. Children that are not going to school, due to ill health or because they are expected to fetch water for the household, also directly impact their nutritional status. The meal these children would get in school is often the only nutritious daily meal children get to eat (10). Not receiving that meal, because of an inadequate WASH environment, feeds into the immediate causes of undernutrition. These direct and indirect pathways between the WASH environment and poor nutritional status are visualised in the conceptual framework above, shown in figure 2 (5).
Undernutrition is a multicausal problem. WASH, together with other underlying causes, significantly contribute to the poor nutritional status of a child. To prevent as many cases of stunting as possible, a multisectoral approach is needed in which silos are merged and both direct and indirect causes are being addressed.
This white paper is written by Nina Leus, MSc Global Nutrition.
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