Relationship between water, sanitation, hygiene, and nutrition: what do Link NCA nutrition causal analyses say?

Defined by UNICEF as ‘the outcome of insufficient food intake and repeated infectious diseases’, undernutrition is one of the world’s most serious problems, with long-lasting harmful impacts on health and devastating consequences for social and economic development. The three main underlying causes of undernutrition, namely unsuitable or insufficient food intake, poor care practices, and infectious diseases, are directly or indirectly related to inadequate access to water, sanitation facilities, and hygiene practices (WASH). There is a growing base of evidence showing the links between poor WASH conditions, especially exposure to poor sanitation, and stunting (low height for age ratio). However, the effects of WASH interventions on wasting (low weight for height ratio) and the impact of environmental enteric dysfunction (chronic infection of small intestine caused by extended exposure to faecal pathogens) on undernutrition should be explored further. Action Against Hunger (Action Contre la Faim) promotes a participatory nutrition causal analysis, the Link NCA methodology, which is used to analyse complex, dynamic, locally specific causes of undernutrition. This article aims to assess the main findings from 12 most recent Link NCA studies, conducted from the beginning of 2014 until the end of 2016. Results show that inadequate WASH conditions are often identified as major contributors to undernutrition in the study areas. The article also provides lessons learned and a set of practical recommendations for better alignment and integration of WASH and nutrition interventions.