Investigating the effects of mycoprotein on glycaemic control and appetite in South Asian and white European adults with type 2 diabetes

Abstract

Type 2 diabetes (T2D) is a disease with a high prevalence in south Asian countries. Diet is the cornerstone strategy for the management of T2D. South Asians may have increased postprandial blood glucose responses following the same dietary challenge compared to white Europeans. Dietary fibre and protein play a role in regulating blood glucose and appetite via a myriad of mechanisms such as gut microbiota fermentation to short-chain fatty acids. Mycoprotein is a food ingredient high in both fibre and protein which has a positive effect on blood glucose and appetite in humans. Likewise, guar gum is a fibre-rich ingredient that decreases blood glucose and appetite in people with T2D. The aim of this thesis is to determine the effect of mycoprotein on glycaemia and energy intake in humans and the mechanisms underpinning these. In Study 1, the associations between mycoprotein-based food consumers and non-consumers with non-communicable disease markers such as blood glucose, energy intake and diet quality are studied in the UK free-living population using the National Diet and Nutrition Survey. The results showed that there is a positive association between mycoprotein consumers and healthy diet scores, fibre, fasting glucose and glycated haemoglobin. In Study 2, a systematic review of the effects of mycoprotein on glycaemic control and appetite in humans is performed. The results showed that the acute effects of mycoprotein on glycaemia are unclear, there is a consistent decrease in insulinaemia and energy intake in healthy humans. In Study 3, the acute effect of mycoprotein and guar gum in glycaemic control and appetite in people with T2D of South Asian and European ethnicity is investigated via a randomised controlled trial. The results showed that mycoprotein decreases postprandial blood glucose and that enriching chapati with guar gum induces a decreased blood glucose response. South Asians, however, had an increased postprandial glucose response compared to white Europeans. In Study 4, the effects of mycoprotein fermentation by the healthy gut microbiota is investigated using in vitro batch fermentation cultures. The results on breath hydrogen, pH, SCFAs, and bacterial communities, showed that mycoprotein may not be fermented.