Nutrient delivery, absorption and utilisation in health and illness

This thesis comprises two distinct but complementary chapters with a broad focus on nutrient delivery and metabolism, encompassing a narrative review, a randomised control trial (RCT) in healthy volunteers, a meta-analysis, a multi-centre prospective observational study, a posthoc analysis and an interventional study protocol in critically ill. The first chapter focuses on the relationships between glycaemia and gastric emptying (GE) in health and Type II Diabetes Mellitus (T2DM) and gastrointestinal function in critical illness, while the second chapter focuses on protein delivery and protein metabolism in critical illness. Delayed gastric emptying is common in T2DM and critical illness and has implications for nutrient delivery and clinical outcomes in critical illness. Glycaemia is one of the factors that can affect GE. The literature is first reviewed to understand relationships between GE and glycaemia and its relevance in community, hospitalised and critical care populations (Chapter 1.2). It has been previously shown that marked hypoglycaemia (blood glucose levels