Background: The blood glucose-lowering effects of β-glucan from oats and barley depend on the amounts consumed and their rheological properties. This has been recently challenged with growing evidence that the food matrix may also be an important factor in predicting its physiological response.
Objective: The objective of this study was to examine the effects of varying doses of β-glucan from oats and barley and added to a snack bar on postprandial glycemia.
Design: In a randomized crossover study, 12 healthy males and females consumed one of 8 snack bars containing 0 (control), 1.5, 3, and 6 g of β-glucan derived from oats or barley or 3 white bread controls. All treatments contained 50 g of available carbohydrate. Blood glucose concentrations were measured after ingestion of the treatments over 2 hours.
Results: Incorporation of 1.5 to 6 g of β-glucan into snack bars had no additional glucose-lowering benefits irrespective of dose and source compared to the control bars (0 g β-glucan), suggesting that both the solid food matrix and composition of the bars may play a role in their effects on glycemic response. All bars reduced blood glucose area under the curve (AUC) by an average of 25% (p < 0.05) compared to the mean of the 3 white bread controls.
Conclusion: Adding β-glucan from oats and barley to the snack bar formulation used in this study did not yield any additional benefits beyond the glucose-lowering effects of the snack bars themselves.
Keywords: barley; oats; postprandial glycemia; viscosity; β-glucan.