A serving of blueberry (Vaccinium corymbosum) improves peripheral vascular function but not metabolic and functional markers in older subjects: A randomized, controlled, crossover study

Evidence suggests that polyphenol-rich foods like berries may help counteract aging-related disorders such as vascular dysfunction and arterial stiffness. However, few intervention studies have been conducted in older adults. This study aimed to assess whether the consumption of blueberries may improve vascular function in older subjects. A randomized, controlled, crossover trial was conducted in a group of 20 volunteers over 60 years old. Participants consumed either a blueberry mousse (250 g, providing 480 mg of anthocyanins - ACNs) or a control product (250 mL of sugared water), with treatments separated by at least 1-week. Reactive hyperemia index (RHI), augmentation index (AIx), blood pressure, and heart rate were measured at baseline and 2 h post-consumption. Blood samples were collected at baseline and after 1, 1.5, 2 and 4 h from the intake to evaluate ACN bioavailability, metabolic, and vascular markers. Sixteen subjects completed the trial (9 males, 7 females; mean age 69 ± 5 years). Blueberry consumption significantly increased RHI compared to control (mean difference + 0.42, 95 % CI: 0.01-0.082, p < 0.05). Maximum serum ACN concentration was observed at 2 h (20.3 ± 7.4 ng/mL). No association was found between RHI improvement and total serum ACNs, but a significant positive correlation was detected with delphinidin and cyanidin-3-glucoside (p < 0.01). No effects on AIx, blood pressure, or other markers were found. In conclusion, blueberries may improve peripheral vascular function in older adults, potentially due to increased ACN levels. Further studies are needed to corroborate these findings and elucidate the mechanisms involved.