Anthocyanins

1. What This Class of Substances Is

Anthocyanins are water-soluble plant pigments belonging to the flavonoid group. They are found in dark berries such as bilberries, blackberries, blackcurrants, elderberries, chokeberries, and cherries, as well as in grape skins, red cabbage, and aubergines. Chemically, they exist as glycosides, with the aglycone (anthocyanidin) bound to sugar. The most common anthocyanidins are cyanidin, delphinidin, malvidin, pelargonidin, peonidin, and petunidin. Extracts such as grape seed or pine bark extract additionally contain oligomeric proanthocyanidins (OPC), which are structurally related. Cocoa flavanols include monomers such as epicatechin and polymeric procyanidins. Bioavailability varies widely: while anthocyanins themselves are poorly absorbed, microbial metabolites formed in the gut may exert systemic effects.

Anthocyanins and their metabolites are difficult to measure directly in humans, as they are rapidly metabolised and excreted renally. Observable effects often arise indirectly via biomarkers such as inflammatory parameters (CRP, IL-6), vascular function (FMD, blood pressure), or cognitive tests (fMRI, reaction time). Controlled studies use standardised extracts or defined food portions to examine dose-response relationships. While animal and cell studies demonstrate mechanisms such as antioxidant or anti-inflammatory effects, their applicability to humans is limited. Chronic effects require long-term studies, as acute measurements often do not reflect clinical relevance.

2. Which Materials Are Included

All substances in the database for which this mechanism of action is described—ordered by the extent of human testing. The numbers represent studies per type of investigation.

3. How Robust the Evidence Is

Well-documented are anthocyanins from berries (126 controlled studies) and grape seed extract (30 controlled studies), followed by cocoa flavanols (8 controlled studies) and pine bark extract (8 controlled studies). These compounds demonstrate consistent effects on cardiovascular parameters, cognitive function, and inflammatory markers. Weaker or only laboratory-tested are, for example, berberine, humic acid complexes, or mineral binders, for which there are few or no controlled human studies. Quercetin, sulforaphane, or astaxanthin are well-documented in cell and animal studies but scarcely tested in humans. Evidence gaps are particularly large regarding long-term effects or specific populations such as children or older adults with multimorbidity.

The compounds reviewed share common mechanisms of action, such as modulation of inflammatory pathways (NF-κB, MAPK), improvement of endothelial function, or influence on the gut microbiome. Anthocyanins and OPC-containing extracts show similar effects on vascular health and cognition, suggesting potential transferability of findings. However, it remains untested whether combinations (e.g., berries plus cocoa) act synergistically or whether specific anthocyanin profiles (e.g., from chokeberry vs. blueberries) produce different effects. The role of microbiome metabolites is also only partially understood. Humic acid complexes or mineral binders could theoretically exert similar antioxidant or detoxifying effects, but systematic human studies are lacking.

4. Key Human Studies

• 1 Enhanced task-related brain activation and resting perfusion in healthy older adults after chronic blueberry supplementation (2017) — Anthocyanins (berries)
• 2 Effects of Anthocyanins on Cardiometabolic Health: A Systematic Review and Meta-Analysis of Randomized Controlled Trials (2017) — Anthocyanins (berries)
• 3 A Review of the Health Benefits of Cherries (2018) — Anthocyanins (berries)
• 4 Effects of grape seed proanthocyanidin extract on menopausal symptoms, body composition, and cardiovascular parameters in middle-aged women: a randomi (2014) — Grape seed extract (OPC)
• 5 Two apples a day lower serum cholesterol and improve cardiometabolic biomarkers in mildly hypercholesterolemic adults: a randomized, controlled, cross (2020) — Grape seed extract (OPC)
• 6 Effects of Grape Seed Proanthocyanidin Extract on Vascular Endothelial Function in Participants with Prehypertension: A Randomized, Double-Blind, Plac (2019) — Grape seed extract (OPC)
• 7 Flavonoid-rich dark chocolate improves endothelial function and increases plasma epicatechin concentrations in healthy adults (2004) — Cocoa flavanols
• 8 Assessing the respective contributions of dietary flavanol monomers and procyanidins in mediating cardiovascular effects in humans: randomized, contro (2018) — Cocoa flavanols
• 9 The Health Effects of Chocolate and Cocoa: A Systematic Review (2021) — Cocoa flavanols
• 10 Treatment of ADHD with French maritime pine bark extract, Pycnogenol (2006) — Pine bark extract
• 11 Effects of low molecular weight procyanidin rich extract from french maritime pine bark on cardiovascular disease risk factors in stage-1 hypertensive (2016) — Pine bark extract
• 12 Pycnogenol® (extract of French maritime pine bark) for the treatment of chronic disorders (2012) — Pine bark extract
• 13 Nutraceutical enhancement of paraoxonase 1 activity in chronic inflammation: A systematic review of animal-based and plant-based nutraceuticals (2026) — Chronic inflammation
• 14 Dietary anthocyanins and the MAPK signaling pathway: from food sources to molecular mechanisms (2026) — Chronic inflammation
• 15 Impact of anthocyanin-rich black rice consumption on cognitive function, inflammation and microvascular function in older adults: a crossover intervention (2026) — Chronic inflammation
• 16 A pilot study of daily blueberry intake and its modulation of gut microbiota enzyme activity in older, sedentary adults with mild depressive symptoms (2026) — Gut microbiome
• 17 Blueberry bioactives as adjunctive nutritional strategies for paediatric neurodevelopmental and emotional-behavioural health: mechanisms, evidence, and (2026) — Gut microbiome
• 18 Gut enterotype- and body mass index (BMI)-dependent effects of anthocyanin supplementation on gut microbiota composition in individuals at risk for comorbidities (2025) — Gut microbiome
• 19 Acute ingestion of a mixed flavonoid and caffeine supplement increases energy expenditure and fat oxidation in adult women: a randomised, crossover clinical trial (2019) — Green tea and EGCG
• 20 Possible effects of dietary polyphenols on sugar absorption and digestion (2013) — Green tea and EGCG
• 21 Plant extracts and natural compounds for the treatment of urinary tract infections in women: mechanisms, efficacy, and therapeutic potential (2025) — Green tea and EGCG
• 22 Inflammatory and metabolic biomarker assessment in a randomised presurgical trial of curcumin and anthocyanin supplements in patients with colorectal (2023) — Turmeric and curcumin
• 23 Research on the correlation between dietary polyphenol supplementation and serum uric acid levels: a meta-analysis of randomised controlled trials (2026) — Turmeric and curcumin
• 24 Rational selection of bioactive principles for wound healing applications: growth factors and antioxidants (2022) — Turmeric and curcumin

5. Open Questions

• Dose-response relationship: What is the minimum effective dose of anthocyanins or OPCs required to achieve clinically relevant effects, and how does this vary between populations (e.g., healthy individuals vs. at-risk groups)?
• Long-term effects: Do sustained, multi-year intakes of anthocyanin-rich foods or extracts produce lasting changes in chronic conditions (e.g., diabetes, dementia)?
• Microbiome interaction: How do individual microbiome profiles influence the metabolism of anthocyanins, and can personalised recommendations be derived from this?
• Combination effects: Are there synergistic effects between anthocyanins and other polyphenols (e.g., flavanols from cocoa) or micronutrients (e.g., vitamin C)?
• Specific anthocyanin profiles: Do cyanidin-rich sources (e.g., blueberries) differ in their effects from delphinidin-rich sources (e.g., blackcurrants) in controlled studies?
• Humic acid complexes: Can the antioxidant or detoxifying effects observed in laboratory and animal studies be replicated in controlled human trials, and which biomarkers are suitable for assessment?
• Transferability of extracts: Can effects observed in studies using high-dose extracts (e.g., grape seed OPCs) be extrapolated to natural food sources, and how do processing methods influence outcomes?

See also the gap list across all compounds. This page is recalculated with each update.