Blueberries and Honeysuckle Berries: Anthocyanin-Rich Polyphenols for Vascular Endothelial Health and Cardiovascular...

Cardiovascular disease remains the world's leading cause of death globally, and there is continuing interest in adjunct, diet-based strategies that may support vascular health alongside guideline-directed pharmacotherapy. Anthocyanin-rich berries are one such option: they are widely consumed, generally safe, and can provide substantial amounts of polyphenols in habitual diets. This narrative review focuses on two anthocyanin-rich species, blueberries (Vaccinium spp.) and haskap/blue honeysuckle (Lonicera caerulea L.), and examines the extent to which their intake may influence vascular endothelial function and cardiometabolic risk markers. For blueberries, which are typically dominated by malvidin- and delphinidin-based anthocyanins together with flavonols, phenolic acids and stilbenes such as pterostilbene, randomized controlled trials and meta-analyses have reported improvements in flow-mediated dilation, with modest effects on blood pressure and arterial stiffness in at-risk populations. Haskap berries, characterized by high levels of cyanidin-3-O-glucoside (C3G) and enriched in iridoids and vitamin C, have been studied mainly in cell and animal models, with early human data suggesting potential effects on vascular function, blood pressure and physical performance. Across both berries, emerging evidence indicates that vascular actions are mediated largely by gut- and host-derived phenolic metabolites rather than by transient circulating parent anthocyanins. We synthesize current knowledge on the phytochemical composition of blueberries and haskap, on molecular pathways implicated in endothelial protection (including NO/eNOS signaling, NRF2-mediated antioxidant defense, NF-κB-driven inflammation, lipoprotein metabolism and platelet activation), and on clinical outcomes related to vascular and cardiometabolic health. On this basis, we outline a mechanistic hypothesis that combined blueberry-haskap interventions could provide additive or synergistic effects on vascular function. This hypothesis is currently supported primarily by preclinical and indirect clinical evidence and should be regarded as hypothesis-generating, highlighting priorities for future mechanism-aware trials rather than constituting a practice-changing recommendation.