Investigating the effectiveness of New Zealand Blackcurrant extract to modulate postprandial glycaemia in overweight/obese individuals

Abstract

Obesity and type 2 diabetes mellitus (T2DM) has now reached epidemic proportions, and therefore strategies to prevent and treat these conditions are required. Long-term adherence to current strategies that primarily revolve around increasing energy expenditure or reducing caloric intake is poor, and therefore alternative therapies need to be investigated. A major component surrounding the progression of obesity to diabetes and further co-morbidities is sustained periods of postprandial hyperglycaemia. Current epidemiological evidence has suggested that habitual anthocyanin intake is linked to lower T2DM risk. The aim of this thesis was to investigate whether anthocyanin-rich New Zealand blackcurrant (NZBC) extract could be an effective nutritional strategy to reduce postprandial glycaemia in overweight and obese individuals. Chapter 2 provides evidence that an acute bolus of NZBC extract is unable to mediate postprandial glucose or triglyceride responses to a carbohydrate-fat test meal, irrespective of the dose used. Therefore, Chapter 3 investigated whether 8 days NZBC extract supplementation is effective at reducing postprandial glucose responses under free-living conditions using continuous glucose monitoring. Chapter 3 showed that NZBC extract supplementation reduced postprandial glucose responses to breakfast and dinner (-9% and -8%, respectively), as well as improving insulin sensitivity (+22%) in overweight/obese individuals. In conclusion, this thesis provides evidence that short-term supplementation with an anthocyanin-rich blackcurrant extract is effective in reducing postprandial glucose responses under free-living conditions, thereby highlighting the potential for anthocyanins to be an effective strategy in mediating postprandial glycaemia and improving insulin sensitivity in individuals at risk of developing type 2 diabetes.