The Bioactive Power of Blueberries: A Review of Vascular and Cognitive Health

Abstract

Blueberry is widely recognized as a functional food due to its high concentration of bioactive compounds. This review synthesizes current scientific evidence, based on clinical trials and meta-analyses, regarding the effects and mechanisms of action of blueberry polyphenols, with a primary focus on anthocyanins, on human health. The literature indicates that the observed benefits are not mediated solely by the parent compounds, but rather by their metabolites (such as phenolic acids, including hippuric acid) generated by the gut microbiota and Phase II metabolism, which demonstrate high bioavailability and are correlated with physiological effects. The primary action of blueberry in the human body includes a robust improvement in vascular health by optimizing endothelial function, as measured by Flow-Mediated Dilation (FMD); an effect that is mechanically attributed to the reduction of oxidative stress and increased nitric oxide bioavailability. In the cognitive domain, blueberry consumption demonstrates neuroprotective actions, significantly improving processing speed, episodic memory, and executive function, with particularly noteworthy benefits in aging populations, those with mild cognitive impairment, or under cognitive fatigue. Furthermore, blueberry plays a significant role in cardiometabolic control, showing an ability to attenuate postprandial glucose and insulin responses and improve long-term markers like HbA1c and triglycerides in at-risk populations. Although effects on blood pressure and fasting lipids (HDL/LDL) are sometimes inconsistent across studies, the collective evidence positions blueberry as a viable dietary intervention to mitigate vascular and cognitive decline.