A bilberry drink with fermented oatmeal decreases postprandial insulin demand in young healthy adults

Yvonne E Granfeldt,Inger Me Björck

doi:10.1186/1475-2891-10-57

Abstract

Backgroundin traditional medicine, blueberries have been used to facilitate blood glucose regulation in type 2 diabetes. Recent studies in diabetic mice have indicated facilitated glycaemic regulation following dietary supplementation with extracts from European blueberries, also called bilberries, (Vaccinium myrtillus). The purpose of the present study was to investigate the impact of fermented oat meal drinks containing bilberries or rosehip (Rosa canina) on glycaemic and insulinaemic responses.Methodsglycaemic and insulinaemic responses in young healthy adults were measured in two series. In series 1, two drinks based on oat meal (5%), fermented using Lactobacillus plantarum 299v, and added with fruit (10%); bilberries (BFOMD) or rose hip (RFOMD) respectively, were studied. In series 2, BFOMD was repeated, additionally, a drink enriched with bilberries (47%) was tested (BBFOMD). As control a fermented oat meal drink (FOMD) was served.Resultsin series 1 the bilberry- and rosehip drinks, gave high glucose responses similar to that after the reference bread. However, the insulin index (II) after the BFOMD was significantly lower (II = 65) (P < 0.05). In series 2 a favourably low insulin demand to BFOMD was confirmed. FOMD gave high glucose response (GI = 95) but, significantly lower insulin response (II = 76). BBFOMD gave remarkably low insulin response II = 49, and tended to lower glycaemia (GI = 79) (P = 0.0684).Conclusiona fermented oat meal drink added with bilberries induced a lower insulin response than expected from the glycaemic response. The mechanism for the lowered acute insulin demand is still unclear, but may be related to some bio-active component present in the bilberries, or to the fermented oat meal base.

Highlights

One important nutritional characteristic of carbohydrate foods concerns their impact on glycaemic regulation and insulin demand
Series 1 The two test products were; 1) a bilberry drink based on bilberry (10%), and, oatmeal (5%), fermented with
Series 2 The test products in series 2 were 1) a bilberry drink based on bilberry (10%), and, oatmeal (5%), fermented with Lactobacillus plantarum 299v (BFOMD) (ProViva®) 2) a fermented oatmeal drink (5%) (FOMD)

Summary

Introduction

One important nutritional characteristic of carbohydrate foods concerns their impact on glycaemic regulation and insulin demand. Quality parameters of importance in this connection are the postprandial glucose and insulin responses, where food characterised by a low glycaemic index (GI) or glycaemic load (GL) have been found to induce benefits on several risk makers for this syndrome as judged from interventions in healthy and type 2 diabetic-subjects [8]. The majority of human and animal studies on blueberries and bilberries have focused on the anti-oxidative properties [11,12,13,14] as evaluated based on serum antioxidant status, and not on the potential effects on glycaemic control. Some in vitro results are available, though, showing potential anti-diabetic capacity of blueberries caused by the presence of specific bioactive components displaying insulin-like properties [15]. Recent studies in diabetic mice have shown decreased blood glucose with bilberry extract [16] and with fermented blueberry juice [17]

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