Comparison of goat milk protein digestibility in adults with and without environmental enteric dysfunction

Undernutrition persists as a major public health issuethat affects 462 million people world-wide with 165 million children beingstunted and 52 million wasted. Both acute (wasting) and chronicmalnutrition (stunting) are associated with significant health and economicburdens in low and middle-income countries (LMICs). With consistent failure orlow effect sizes observed in nutrient supplementation interventions toalleviate under nutritional status, the impact of a poor environment on growthgained importance. A condition termed environmental entericdysfunction (EED) was identified, akin to tropical enteropathy, with featuresof gut dysfunction such as villous atrophy, disruption of the normal gutmicrobiota, altered gut barrier function, increased local and systemicinflammation, and bacterial translocation, leading to increased intestinalpermeability. As a consequence of the gut abnormality noted, thereis potential for reduced nutrient digestion and absorption that could lead tolow availability of nutrients to meet the body’s demands, which in turninfluences the functionality of the individual. However, there are no studies inhumans demonstrating this reduced digestive and absorptive capacity for nutrientsparticularly in an EED context. There is a lack of consensus on reliablediagnostic tests available for EED, in spite of multiple biomarkers that havebeen proposed and studied that relate to the various domains of EED.The dual sugar absorption test (lactulose with mannitol or rhamnose) is widelyaccepted for the assessment of intestinal permeability, albeit its associated limitations.Therefore, this study aims to first, identify adults with EED using the dualsugar absorption test, second, to determine the absorptive and digestivecapacity of amino acids in these individuals. The absorptive capacity will beassessed by adopting an inert stable amino acid isotope (allo-isoleucine), andthe digestion will be measured using the recently development dual stableisotope tracer technique. The intrinsically 2H labeledgoat milk will be used in the digestion protocol. In addition to this, otherintestinal inflammatory markers in the plasma and feces (plasma kynureninetryptophan ratio [KTR] and fecal neopterin, myeloperoxidase [MPO], alpha-1antitrypsin [AAT]) and pancreatic exocrine function (13C-Mixedtriglyceride [MTG], Fecal Elastase-1[FE-1]) will be assessed andcorrelated with digestion/absorption in the same set of adults, in order toadvance 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.