Effects of Enriched Fruit Juice on Blood Glucose Levels After a Meal in Healthy Subjects

Results from a large number of studies in humans have shown that diets rich in foods that give lower glucose response bring lower risk of type 2 diabetes. Polyphenols, naturally found in fruits, vegetables and grains, have shown the potential to attenuate post-prandial blood glucose spikes following a carbohydrate-rich meal, through partial inhibition of the main enzymes of carbohydrate digestion and reduction in glucose and fructose transport from the gut after digestion and by enhancing the insulin action after glucose reaches the bloodstream. This study is designed to determine whether polyphenols, as normally and naturally present in food extracts and beverages, added to a carbohydrate-rich meal, can lower blood glucose levels after its consumption, and hence lower its glycaemic index, and if this effect is mediated through effects on insulin and other hormones. The study is designed as an acute, double-blind, randomised, placebo-controlled crossover trial in 24 healthy subjects with normal glycaemic response to white bread. Participants will be asked to consume either white bread with pomegranate juice enriched with extracts from grape seeds and apple peels or white bread with placebo drink. The effects on plasma glucose levels, levels of hormones and other biomarkers involved in postprandial response will be determined over 3 hours after the consumption.