Undernutrition persists as a major public health issue that affects 462 million people world-wide with 165 million children being stunted and 52 million wasted. Both acute (wasting) and chronic malnutrition (stunting) are associated with significant health and economic burdens in low and middle-income countries (LMICs). With consistent failure or low effect sizes observed in nutrient supplementation interventions to alleviate under nutritional status, the impact of a poor environment on growth gained importance. A condition termed environmental enteric dysfunction (EED) was identified, akin to tropical enteropathy, with features of gut dysfunction such as villous atrophy, disruption of the normal gut microbiota, altered gut barrier function, increased local and systemic inflammation, and bacterial translocation, leading to increased intestinal permeability. As a consequence of the gut abnormality noted, there is potential for reduced nutrient digestion and absorption that could lead to low availability of nutrients to meet the body’s demands, which in turn influences the functionality of the individual. However, there are no studies in humans demonstrating this reduced digestive and absorptive capacity for nutrients particularly in an EED context. There is a lack of consensus on reliable diagnostic tests available for EED, in spite of multiple biomarkers that have been proposed and studied that relate to the various domains of EED. The dual sugar absorption test (lactulose with mannitol or rhamnose) is widely accepted for the assessment of intestinal permeability, albeit its associated limitations. Therefore, this study aims to first, identify adults with EED using the dual sugar absorption test, second, to determine the absorptive and digestive capacity of amino acids in these individuals. The absorptive capacity will be assessed by adopting an inert stable amino acid isotope (allo-isoleucine), and the digestion will be measured using the recently development dual stable isotope tracer technique. The intrinsically ²H labeled goat milk will be used in the digestion protocol. In addition to this, other intestinal inflammatory markers in the plasma and feces (plasma kynurenine tryptophan ratio [KTR] and fecal neopterin, myeloperoxidase [MPO], alpha-1 antitrypsin [AAT]) and pancreatic exocrine function (¹³C-Mixed triglyceride [MTG], Fecal Elastase-1[FE-1]) will be assessed and correlated with digestion/absorption in the same set of adults, in order to advance understanding of the interlinked mechanistic pathways proposed in EED. The study is proposed in adults rather than children, as it is invasive in nature where the labeled amino acid will be intravenously infused.