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
A 2026 systematic review and meta-analysis of 32 randomized controlled trials in overweight and obese populations found that polyphenol interventions can reduce pro-inflammatory IL-6 and increase anti-inflammatory IL-10, with outcomes shaped by duration, dose, and food matrix.[2]
Whole polyphenol-rich foods outperformed purified extracts for lowering IL-6 and C-reactive protein (CRP), suggesting that the broader food matrix may amplify anti-inflammatory effects.[2:1]
Anti‐carcinogenic (anticancer)
Antimicrobial
Polyphenols such as anthocyanins, flavonoids, and phenolic acids are found to have antimicrobial properties.[3]
Antiviral
Berries such as Elderberry, blueberry, raspberry, and cranberry have proven to be effective against viral infections.[3:1]
Berries could be an alternative source for managing and inhibiting viral infections.[3:2]
Digestion
Prebiotic
Polyphenols have prebiotic effects; stimulate the growth of healthy gut microorganisms and increase production of Short Chain Fatty Acids.[4]
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.[4:1]
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%).[5]
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.[5:1]
The authors emphasized that short intervention duration, methodological variability, and individual microbiome metabotypes likely explain part of the inconsistent response magnitude across trials.[5:2]
A separate 2026 systematic review and meta-analysis focused specifically on overweight and obese populations found that polyphenol interventions promoted beneficial gut bacteria such as Bifidobacterium spp. and Akkermansia muciniphila, while the strongest anti-inflammatory effects were seen in interventions lasting under 6 weeks.[2:2]
Endurance
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 ↩︎Title: Effects of Polyphenols on Gut Health and Inflammation in Overweight and Obese Populations: A Systematic Review and Meta-analysis of Dose, Duration, and Food Matrix
Publication: Nutrition Reviews
Date: March 11, 2026
Study Type: Systematic Review and Meta-analysis of Randomized Controlled Trials
Author(s): Qianqian Wang, Huimin Zou, Yu Zhang, Kai Huang, Xiao Guan, Suijun Wang, Sen Li
Notes: 32 randomized controlled trials in overweight and obese populations; subgroup analyses found shorter interventions and higher doses more strongly reduced IL-6 and raised IL-10, while whole-food interventions outperformed purified extracts for lowering IL-6 and CRP.
Copy: Source ↩︎ ↩︎ ↩︎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 ↩︎ ↩︎ ↩︎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 ↩︎ ↩︎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 ↩︎ ↩︎ ↩︎