The Combined Effects of Pea Protein and Blueberries on Postprandial Glucose Response and satiety in Healthy Adults

The rising prevalence of type 2 diabetes highlights the need for effective dietary strategies to manage postprandial glycaemia (1) . Plant-based compounds such as plant proteins and polyphenol-rich berries are gaining increasing attention for their potential to modulate glucose metabolism. Blueberries, rich in anthocyanins, have been shown to reduce postprandial glucose spikes by delaying starch digestion. This effect is largely attributed to their ability to inhibit carbohydrate digestive enzymes (α-amylase and α-glucosidase) and glucose transporters (2) . It is hypothesised that the presence of undigested starch in the lower gastrointestinal tract can stimulate the secretion of gut hormones thereby promoting satiety and regulating glucose homeostasis (2) . Pea protein, on the other hand, has independently been shown to reduce postprandial glucose levels, modulate insulin response, and stimulate gut hormone release (3) . A targeted combination of both, protein and anthocyanin-rich blueberries could therefore provide a more efficient intervention. In a randomised, controlled, double blinded crossover study, 10 healthy participants consumed one of four test beverages accompanied by 50 g of available carbohydrate from white bread: flavoured water (CHO), blueberries (BB), pea protein (PP), and a combination of pea protein and blueberries (BBPP). Postprandial responses were assessed over 180 minutes using continuous glucose monitoring (CGM) for glucose levels and Visual Analogue Scale (VAS) ratings for satiety, both recorded at 30-minute intervals. The effect of the interventions on peak postprandial glucose responses and satiety levels were evaluated using a two-factor repeated measures ANOVA. All statistical analyses were performed using GraphPad Prism with a statistical difference of p < 0.05 considered as significant. All test drinks resulted in lower postprandial glucose levels compared to the control (CHO), with the greatest reduction observed in the BBPP group. Peak glucose levels were significantly lower in the BBPP group (0.9 mmol/L, p<0.05) compared to CHO (1.5 mmol/L), BB (1.3 mmol/L), and PP (1.1 mmol/L). Additionally, the BBPP group exhibited the lowest incremental area under the curve (iAUC = 88.58 mmol·min/L, p < 0.05), while the other groups had similar iAUC values around 130 mmol·min/L. Both the PP and BBPP groups showed delayed times to peak glucose (Tmax = 90 min) compared to the CHO and BB groups (Tmax = 75 min), indicating a slower and more gradual glucose response. In terms of satiety, both the PP and BBPP interventions significantly increased subjective satiety ratings (80–90%) compared to the CHO and BB groups (50–60%) 60min post meal, although the difference between BBPP and PP was not statistically significant. Combining Pea protein with blueberry polyphenols synergistic benefits in reducing postprandial glucose excursions. These findings provide promising evidence to support the development of functional foods aimed at improving glucose management and metabolic health.