Low-dose galactose to control postprandial glycaemia

Context Controlling blood sugar levels after meals is an important component of health. Excessive rises in blood sugar levels form the basis for diagnosing diabetes but are also relevant to the general population. Even modestly increased blood sugar levels for a period of time can increase fasting glucose and impair insulin sensitivity and secretion. Understanding postprandial blood sugar regulation is therefore important for the maintenance of health across the lifespan. Controlling postprandial glycaemia even within the generally healthy population, can benefit health and longevity. Challenge and Opportunity Current nutritional approaches for blood sugar control normally rely on changing foods that are eaten or result in undesirable effects such as increased insulin levels. Our pilot data suggest that adding a small amount (equivalent to just over one teaspoon) of the milk sugar, galactose, can prevent excessive rises in blood sugar levels without compromising on insulin levels. If this is confirmed, and underlying mechanisms understood, this provides a new approach to control blood sugar levels without needing to avoid/substitute preferred foods. People could eat their preferred foods with added low-dose galactose (imperceptible in a meal) for better blood sugar control. Aims and Objectives This project will establish the degree to which adding low-dose galactose to a meal can control blood sugar levels. People will consume standardised glucose drinks (75g glucose, as an oral glucose tolerance test). People will consume these with and without the addition of galactose, and with the addition of another sugar (fructose) for an extra comparison. We will use state-of-the-art labelling methods (dual stable isotope technology) to follow what happens to the glucose that is ingested and understand what happens to sugar being released by the liver and sugar being taken up by other tissues like the muscles. These methods can tell us how the addition of galactose can control blood sugar levels. For example, the galactose could slow down the appearance of glucose from the gut and/or liver released into the blood, or it could increase the disappearance of glucose from the blood into muscles. We will measure the appearance of our label on exhaled breath, which will establish whether ingested sugar is stored, or burned as fuel. We will also explore other potential ways in which galactose might control blood sugar levels by measuring key hormones and metabolites that contribute to blood sugar control (for example, insulin, fatty acids, and incretin hormones which potentiate insulin secretion). This additional evidence of how galactose can control blood sugar levels will provide the understanding required to best make use of this approach across a variety of settings. Applications and Benefits The findings from this project will several applications and benefits, including a better basic understanding of the nutritional regulation of blood sugar control. The evidence can be incorporated into public health guidelines and improve population health, and in healthcare settings for targeted nutritional strategies for blood sugar control. The food industry can benefit from this evidence to provide a rationale to produce new food products and novel application of galactose as a functional food ingredient. Furthermore, this novel application can repurpose a by-product of the dairy industry (lactose) into a value-added product, thereby having economic and environmental benefits. This will also train early-career scientists in important scientific methods of nutrition research and product development.