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What are Polyphenols?

Polyphenols are a structural class of mainly natural, but also synthetic or semisynthetic, organic chemicals. They are considered micronutrients.

Anthocyanins

Flavonoids

Catechins

Epigallocatechin gallate (EGCG)

Ellagic acid

Proanthocyanidins

Pterostilbene (PSB)

Pterostilbene (PSB) (3′,5′‐dimethoxy‐resveratrol), a Resveratrol‐related polyphenol found in blueberries, was identified. PSB has a higher bioavailability than Reveratrol due to the presence of two methoxy groups that increase its lipophilic and oral absorption.[1]

Resveratrol

Healing Properties

Antioxidant

Anti‐inflammatory

Anti‐carcinogenic (anticancer)

Antimicrobial

Polyphenols such as anthocyanins, flavonoids, and phenolic acids are found to have antimicrobial properties.[2]

Antiviral

Berries such as Elderberry, blueberry, raspberry, and cranberry have proven to be effective against viral infections.[2:1]

Berries could be an alternative source for managing and inhibiting viral infections.[2:2]

Digestion

Prebiotic

Polyphenols have prebiotic effects; stimulate the growth of healthy gut microorganisms and increase production of Short Chain Fatty Acids.[3]

Consumption of polyphenols, especially catechins, anthocyanins and proanthocyanidins, increases the abundance of Lactobacillus, Bifidobacterium, Akkermansia, Roseburia, and Faecalibacterium spp. Moreover, polyphenols supplementation increased the production of short-chain fatty acids (SCFA), including butyrate. The clinical trials showed an increased abundance of Lactobacillus acidophilus, Bifidobacterium and Faecalibacterium spp., and a reduction in plasma lipopolysaccharide-binding protein after the consumption of anthocyanins and ellagic acid. In conclusion, there is strong evidence in preclinical studies that dietary polyphenols can stimulate both the growth of microorganisms identified as prebiotic targets and an increase in the production of SCFA.[3:1]

A 2026 systematic review and meta-analysis of human intervention studies found a significant increase in Bifidobacterium abundance after polyphenol-rich interventions (SMD = 0.81; 95% CI: 0.18-1.44; p = 0.0114), despite substantial between-study heterogeneity (I2 = 77.4%).[4]

The same review reported that flavonoids, phenolic acids, and anthocyanin-rich foods (including berries, grape-derived interventions, and green tea) were commonly associated with higher Bifidobacterium, Lactobacillus, and Faecalibacterium, with concurrent improvements in metabolic and inflammatory markers in multiple study populations.[4:1]

The authors emphasized that short intervention duration, methodological variability, and individual microbiome metabotypes likely explain part of the inconsistent response magnitude across trials.[4:2]

Endurance


  1. Title: Pterostilbene reduces colonic inflammation by suppressing dendritic cell activation and promoting regulatory T cell development
    Publication: The Federation of American Societies for Experimental Biology
    Institution(s): Tokyo University of Science, Tokyo, Japan
    Date: September 2020
    Archive ↩︎

  2. Title: Berry derived constituents in suppressing viral infection: Potential avenues for viral pandemic management
    Institution(s): University of Illinois, Rockford, IL
    Publication: Elsevier: Clinical Nutrition ESPEN
    Date: September 28, 2021 ↩︎ ↩︎ ↩︎

  3. Title: Prebiotic effect of dietary polyphenols: A systematic review
    Publication: Journal of Functional Foods
    Institution(s): School of Nutrition, Federal University of Goiás (UFG), Goiânia, Goiás, Brazil
    Date: September 2020
    Archive ↩︎ ↩︎

  4. Title: Dietary Polyphenols as Modulators of Bifidobacterium in the Human Gut Microbiota
    Publication: Nutrients
    Date: 2026
    Study Type: Systematic Review and Meta-Analysis (Human Intervention Studies)
    Author(s): Corina Dalia Toderescu, Mohamudha Parveen, Svetlana Trifunschi, Alexandru Oancea, Gentiana Camelia Ciubuc Jurj, Iulia Gabriela Cresneac, Melania Florina Munteanu, Ioana Ciopanoiu, Casiana Boru, Elena Narcisa Pogurschi, Catalin Ionite, Alina Stefanache, Ionut Iulian Lungu
    Copy: Source, PDF ↩︎ ↩︎ ↩︎