Nutritional Strategies and Bioactive Compounds: Vaccinium myrtillus L. and Ribes nigrum and Their Anti-Inflammatory, Antioxidant, Potential Preclinical Anticancer, and Microbiota-Related Effects

Anthocyanin-rich preparations derived from bilberry (Vaccinium myrtillus L.) and blackcurrant (Ribes nigrum), whether standardized or otherwise analytically characterized, have been investigated for their potential to modulate chronic low-grade inflammation and oxidative stress. This narrative review focuses on human intervention studies using preparations explicitly derived from these species and contextualizes microbiota-related mechanisms and potential anticancer pathways using selected preclinical evidence. Human studies primarily report changes in inflammatory, endothelial, and oxidative-stress biomarkers, including hsCRP, IL-6, TNF-α, adhesion molecules, malondialdehyde, urinary 8-iso-PGF2α, and urinary 8-OHdG; however, findings are heterogeneous across formulations, doses, populations, intervention durations, and endpoints. Evidence for clinically meaningful outcomes remains limited. Studies of purified anthocyanins without unequivocal botanical sourcing are considered background evidence and are not used to substantiate species-specific claims. Mechanistically, intact anthocyanins have low systemic bioavailability, and colonic microbial metabolism generates phenolic metabolites that may interact with SCFA-related and barrier–immune pathways; however, causal relationships in humans remain insufficiently established. Potential anticancer mechanisms are supported predominantly by in vitro and animal studies and should therefore be considered hypothesis-generating rather than evidence of clinical efficacy. Overall, bilberry and blackcurrant preparations warrant further investigation in adequately powered, longer-duration human trials with transparent botanical characterization and clinically relevant endpoints.