The acute effect of food structure on post prandial glucose and subsequent metabolic responses

Abstract

Glucose is a major molecule for energy supply. Thus, the movement of glucose from food into tissues is necessary for survival. However, since high levels of glucose are toxic to the body, glucose homeostasis plays a key role in preventing a number of diseases, including type 2 diabetes, obesity, coronary heart disease and many types of cancer. Empirical evidence has shown that postprandial glucose and insulin sensitivity are not only governed by the content of food but also by other factors that may play a role in the digestive process, including food structure, rheological properties and food breakdown pattern. The combination of different levels of structure—from the molecular to the micro and macro levels—develops the rheological behavior of food that impacts the availability and digestibility of nutrients. In this work, I brought together nutritional physiology and rheology to explore the impact of peas and chickpeas on postprandial glycaemia and to develop a better understanding of how their physical properties change the physiological response. This in turn will give insight into the effect of food structure and its rheological properties on postprandial metabolic responses. The main finding of this work highlighted the importance of an intact cell wall in lowering postprandial glycaemia and subsequent metabolic responses when compared to a ruptured structure. Also, this work showed that starch structure played a role in postprandial glycaemia and insulinemia when the cell wall is absent. Further investigation was performed on the rheological properties of foods with different structures, relating these results with metabolic responses. Results from studies assessing the rheological and mechanical properties of food strongly suggested that they indeed affect the food breakdown pattern during digestion. It was shown that an intact structure’s rheological properties slowed the breakdown of food during digestion. Also, different intact structures had different rheological properties that suggested an impact on the food’s behaviour during digestion and hence on postprandial metabolic responses. Throughout this thesis, an indirect relation between food structure, its rheological properties, food breakdown during digestion in relation to postprandial glycaemia and related metabolic responses was realised.