Addressing endemic stunting remains a primary United Nations development goal. One potential contributor to global linear growth failure is environmental enteric dysfunction (EED). However, it has proven challenging to address with interventions focused on water, sanitation and hygiene. Initial theories of EED placed primacy on recurrent enteric exposures; however, it appears that these exposures are inadequate to explain the phenotype and sequelae. Children in EED endemic regions are at high risk of having inadequate nutrition, and strong associations can be found between malnutrition and stunting. In this review, we summarize the clinical, translational and mechanistic evidence linking intake of animal source foods as a source of protein and micro-nutrients and, in their absence, essential amino acid (EAA) deficiency with stunted growth and features of EED such as altered immune behaviour. EAA deficiency has been linked to growth failure through several mechanistic pathways including intestinal inflammation, barrier disruption and chondral plate closure, and amino acid supplementation has shown clinical efficacy. By better understanding this linkage, we will be able to better study not only EED but also pathways in which dietary sources mechanistically alter systemic signalling in metabolism and immune function. This article is part of the theme issue 'Biological, biomedical and environmental drivers of stunting'.
Khan et al. (Thu,) studied this question.