Hoggard, N., Cruickshank, M., Moar, K.M., Bestwick, C., Holst, J.J., Russell, W. and Horgan, G.W.
Journal of Nutritional Science.
bilberry, anthocyanins, type 2 diabetes, glycaemic response.
||Dietary strategies for alleviating health complications associated with type 2 diabetes (T2D) are being pursued as alternatives to pharmaceutical interventions. Berries such as bilberries that are rich in polyphenols may influence carbohydrate digestion and absorption and thus postprandial glycaemia. In addition berries have been reported to have anti-incretin, anti-oxidant and anti-inflammatory properties that may also affect postprandial glycaemia. This study investigated the acute affect of a standardised bilberry extract on glucose metabolism in T2D.
Male volunteers with T2D (n=8, BMI 30, SD 4) controlling their diabetes by diet and lifestyle alone were given a single oral capsule of either 0.47g standardized bilberry extract (36% (w/w) anthocyanins) which equates to ∼50 g of fresh bilberries or placebo followed by a polysaccharide drink (equivalent to 75 g glucose) in a double blinded cross over intervention with a two week wash out period between capsules. The ingestion of the bilberry extract result in a significant decrease in AUCi for both glucose (p=0.003) and insulin (p=0.03) compared with the placebo. There was no change in the gut (GLP-1, GIP), pancreatic (glucagon, amylin) or anti-inflammatory (MCP-1) peptides. In addition there was no change in the anti-oxidant (TEAC, FRAP) responses measured between the volunteers receiving the bilberry extract and the placebo.
In conclusion this is demonstrates for the first time that the ingestion of a concentrated bilberry extract reduces postprandial glycaemia and insulin in volunteers with T2D. The most likely mechanism for the lower glycaemic response involves reduced rates of carbohydrate digestion and/or absorption.