Probiotic fruit beverages with different polyphenol profiles attenuated early insulin response

Abstract

Background: Consumption of polyphenol-rich fruits and vegetables may improve postprandial glucose and insulin levels and hence promote well-being. Previously it has been observed that consumption of bilberry decreases the postprandial insulin demand. The intention with the present study was to compare the impact of different supplements with various polyphenol profiles, on the postprandial glucose and insulin responses in healthy young adults.

Methods: In a randomized, controlled, crossover study the postprandial glycemic and insulin responses were observed in eleven healthy adults after intake of five different beverages containing bilberry (European blueberry), blackcurrant, beetroot, mango and rose hip, respectively; all drinks were enriched with the same composition of fermented oatmeal and probiotics. The control was a glucose drink. The profile and content of the polyphenols in the different beverages were determined by HPLC-DAD analysis. The antioxidative capacity of the different beverages were measured by TEAC and DPPH assays.

Results: Beverages containing bilberry, blackcurrant, mango or rose hip significantly attenuated the early postprandial insulin response (0-90 min), but showed no effect on glucose response. Drinks with bilberry or rose hip reduced the insulin response from the very early phase (0-30 min), and had significantly lower insulin index compared with the control. The efficiency of the bilberry and rose hip to decrease early postprandial insulin responses correlated with higher phenolic contents.

Conclusions: Supplements with bilberry, blackcurrant, mango or rose hip in the tested probiotic and oatmeal enriched beverage attenuated early-phase insulin response, but had no effect on the postprandial glycemic response. The improved ability of bilberry and rose hip to lower the very early phase of insulin response seems to be due to a higher phenolic content.

Trial registration: The study was retrospectively registered at ClinicalTrials.gov with number NCT03159065 .

Keywords: Beetroot; Bilberries; Blackcurrant; Mango; Postprandial insulin response; Rose hip.

Conflict of interest statement

Ethics approval and consent to participate

The study was approved by the Ethics Committee of the Faculty of Medicine at Lund University, Sweden (Dnr 2014/435), and all individuals gave written informed consent to participate in the study.

Consent for publication

Not applicable

Competing interests

The author MA is employed at ProViva AB and ILA is employed at Probi AB.

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Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures

Fig. 1

Incremental blood glucose response curve during the two-hour postprandial period. The change in blood glucose concentration was calculated by deducting the basal level from the blood glucose level measured after intake of the test drinks and was represented as delta blood glucose. Median values were plotted

Fig. 2

Incremental serum insulin response curve during the two-hour postprandial period. The change in serum insulin concentration was calculated by deducting the basal level from the insulin level measured after intake of the test drinks and was represented as delta serum insulin. Median values were plotted. Median values with different letters denote significant differences between Beetroot and Bilberry, and between Beetroot and Rose hip (P < 0.05)

Fig. 3

Orthogonal projections to latent structures discriminant analysis (OPLS-DA) score plots of postprandial responses data. a Model calculated to discriminate between Bilberry and Glucose (described response variation, R2Y = 0.63; predicted response variation, Q2Y = 0.48). b Model discriminating between Rose hip and Glucose (R2Y = 0.43, Q2Y = 0.32). The x-axis in (b) consists of the 22 analyzed samples. Grey dashed line shows 1.04376*(±2SD) and the black dashed line 1.04376*(±3SD)

Fig. 4

Orthogonal projections to latent structures discriminant analysis (OPLS-DA) model calculated on polyphenol profiles and discriminating between Bilberry and Rose hip (Bil_Rose class) and other tested beverages (described response variation, R2Y = 0.977; predicted response variation, Q2Y = 0.973). The difference between the two classes of berries was explained by 31.6% of the variation in polyphenol data. a Score scatter plot. b Loadings bar plot showing the driving forces for the observed cluster separation. The Bil_Rose class had higher levels of phenolics as compared to the other berries