Research

Polyphenols

28 peer-reviewed studies curated from PubMed and Semantic Scholar.

1
Meta-analyses
1
Systematic reviews
21
RCTs
5
Other studies
Meta-analyses (4%)
Systematic reviews (4%)
RCTs (75%)

Studies

Sorted by quality and recency

2024·Obesity (Silver Spring, Md.)·Hila Zelicha, Alon Kaplan, Anat Yaskolka Meir, et al

Altered proteome profiles related to visceral adiposity may mediate the favorable effect of green Mediterranean diet: the DIRECT-PLUS trial.

RCTn = 294Heart Health Inflammation

The DIRECT-PLUS trial explored the effects of a green Mediterranean diet, high in polyphenols and low in red/processed meat, on cardiovascular disease and inflammation-related proteins in 294 participants with abdominal obesity. The green-MED diet led to more pronounced beneficial changes in proinflammatory proteins and was associated with reductions in visceral adiposity and cardiometabolic risk over 18 months.

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2022·Advances in nutrition (Bethesda, Md.)·Andrea Del Saz-Lara, María-Carmen López de Las Hazas, Francesco Visioli, et al

Nutri-Epigenetic Effects of Phenolic Compounds from Extra Virgin Olive Oil: A Systematic Review.

Systematic review

Systematic review of 51 articles examining the epigenetic effects of extra virgin olive oil (EVOO) and its phenolic compounds (OOPCs). The review found that EVOO and its OOPCs can induce epigenetic changes that regulate gene expression, impacting metabolic processes and diseases such as cancer, cardiovascular, and neurodegenerative diseases.

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2020·PloS one·Rayudika Aprilia Patindra Purba, Pramote Paengkoum, Siwaporn Paengkoum

The links between supplementary tannin levels and conjugated linoleic acid (CLA) formation in ruminants: A systematic review and meta-analysis.

Meta-analysisn = 3,712

A systematic review and meta-analysis of 38 publications with 3712 treatments examined the effects of dietary tannins on conjugated linoleic acid (CLA) formation in ruminant-derived products. The study found that increased dietary tannins generally led to increased CLA formation and Δ9 desaturation in milk and meat, though no changes were observed in rumen fermentation characteristics. The in vivo method was deemed more suitable for observing fatty acid transformation than the in vitro method.

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2025·Clinical nutrition (Edinburgh, Scotland)·Dafna Pachter, Anat Yaskolka Meir, Alon Kaplan, et al

Serum Galectin-9 and Decorin in relation to brain aging and the green-Mediterranean diet: A secondary analysis of the DIRECT PLUS randomized trial.

RCTn = 294Brain Health

Secondary analysis of the 18-month DIRECT PLUS trial with 294 participants randomized to different diets, including a green-MED diet high in polyphenols. The study found that higher serum levels of Galectin-9 and Decorin were associated with accelerated brain aging, but the green-MED diet significantly decreased Galectin-9 levels, suggesting a beneficial effect on brain health.

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2023·The American journal of clinical nutrition·Eleanor Wood, Sabine Hein, Robin Mesnage, et al

Wild blueberry (poly)phenols can improve vascular function and cognitive performance in healthy older individuals: a double-blind randomized controlled trial.

RCTn = 61Brain Health Heart Health

A double-blind RCT in 61 healthy older individuals assessed the effects of 26 g freeze-dried wild blueberry powder on vascular and cognitive function. The WBB group showed significant improvements in flow-mediated dilation, reduced systolic blood pressure, and enhanced cognitive performance compared to placebo. No changes in cerebral blood flow or gut microbiota were observed.

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2021·Journal of cosmetic dermatology·Julia Welzel, Helmut H Wolff, Wolfgang Gehring

Reduction of telogen rate and increase of hair density in androgenetic alopecia by a cosmetic product: Results of a randomized, prospective, vehicle-controlled double-blind study in men.

RCTn = 62Skin Hair Health

RCT assessing a foam containing nicotinic acid hexyl ester, polyphenols, zinc, glycine, and caffeine in men with androgenetic alopecia over 6 months. The verum group showed a significant reduction in telogen rate compared to the vehicle group, indicating a benefit for cosmetic intervention against male pattern hair loss.

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2021·Nutrients·Jieping Yang, Patrick Kurnia, Susanne M Henning, et al

Effect of Standardized Grape Powder Consumption on the Gut Microbiome of Healthy Subjects: A Pilot Study.

RCTGut Health Heart Health

Pilot study evaluating the effect of 46 g of grape powder consumption on the gut microbiome and cholesterol/bile acid metabolism in healthy adults. Grape powder consumption significantly increased gut microbiome diversity and decreased total cholesterol and HDL cholesterol, with trends of decreasing LDL cholesterol and total bile acid.

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2025·Nutrients·Udomlak Sukatta, Prapassorn Rugthaworn, Ketsaree Klinsukhon, et al

Synergistic Effects of Microencapsulated Polyphenols and Concurrent Training on Metabolic Health and Fitness in Overweight/Obese Adults with Prediabetes.

RCTn = 43Inflammation Physical Performance

This randomized, single-blind, placebo-controlled trial investigated the effects of concurrent training and a microencapsulated persimmon-karonda polyphenol formulation on metabolic health in overweight/obese adults with prediabetes. The combined intervention showed the greatest improvements in glycemic indices, inflammatory markers, and physical fitness compared to placebo.

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2024·Nutrients·Álvaro Fernández-Cardero, José Luis Sierra-Cinos, Laura Bravo, et al

Consumption of a Coffee Rich in Phenolic Compounds May Improve the Body Composition of People with Overweight or Obesity: Preliminary Insights from a Randomized, Controlled and Blind Crossover Study.

RCTn = 38Physique

This randomized, controlled, single-blind crossover study analyzed the effects of two types of coffee with different phenolic content on body composition in 60 overweight or obese participants. Consumption of lightly roasted coffee (LRC) and roasted coffee (RC) reduced fat mass and body fat percentage, with LRC showing a slightly greater effect. Muscle mass and muscle mass percentage increased slightly, but there were no significant changes in metabolic syndrome variables or body weight.

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2023·International journal of molecular sciences·Alyne Lizane Cardoso, Luciane de Lira Teixeira, Neuza Mariko Aymoto Hassimotto, et al

Kinetic Profile of Urine Metabolites after Acute Intake of a Phenolic Compounds-Rich Juice of Juçara (Mart.) and Antioxidant Capacity in Serum and Erythrocytes: A Human Study.

RCTn = 10Inflammation

A clinical trial evaluated the absorption and excretion of bioactive compounds in urine and the antioxidant capacity in serum and erythrocytes of 10 healthy subjects after juçara juice intake. Juçara juice decreased the total oxidant status of serum and increased phenolic acid metabolites excretion, indicating its antioxidant capacity.

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2022·European journal of nutrition·Othman K Qadir, Chris J Seal, Ammar W Ashor, et al

Double-blind controlled dietary cross-over intervention with differentially fertilised intact lettuce leaves shows acute reduction in blood pressure in young adults, associated with faster uptake of nitrate than of phenolics.

RCTn = 19Heart Health

This double-blind controlled dietary cross-over intervention studied the acute effects of lettuce with high nitrate versus high phenolic content on blood pressure in 19 healthy young adults. The high nitrate lettuce significantly reduced systolic blood pressure within 6 hours, correlating with increased plasma and salivary nitrate levels.

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2022·European journal of nutrition·Simone Buerkli, Laura Salvioni, Natalie Koller, et al

The effect of a natural polyphenol supplement on iron absorption in adults with hereditary hemochromatosis.

RCTn = 14Nutrition

A multi-center, single-blind, placebo-controlled cross-over study assessed the effect of a polyphenol supplement (PPS) on iron absorption in 14 patients with hereditary hemochromatosis. The PPS, containing black tea powder, cocoa powder, and grape juice extract, reduced fractional iron absorption by approximately 40% compared to placebo.

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2021·The Journal of nutrition·Meryem Lazrak, K. El Kari, Nicole U. Stoffel, et al

Tea Consumption Reduces Iron Bioavailability from NaFeEDTA in Nonanemic Women and Women with Iron Deficiency Anemia: Stable Iron Isotope Studies in Morocco.

RCTn = 46Nutrition

RCT in Morocco assessing iron bioavailability from NaFeEDTA in wheat flour-based meals consumed with and without tea in nonanemic women and women with iron deficiency anemia. Tea consumption reduced iron absorption by over 85% in both groups, indicating that tea polyphenols significantly inhibit iron absorption.

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2020·Molecules (Basel, Switzerland)·Xuhuiqun Zhang, Amandeep Sandhu, Indika Edirisinghe, et al

Plasma and Urinary (Poly)phenolic Profiles after 4-Week Red Raspberry (L.) Intake with or without Fructo-Oligosaccharide Supplementation.

RCTn = 35

This randomized crossover clinical trial investigated the effect of 4-week red raspberry supplementation on (poly)phenolic metabolism in adults with prediabetes and insulin-resistance. The study also examined whether adding fructo-oligosaccharides would augment the microbial metabolites of raspberry (poly)phenols. Results showed significant increases in several metabolite groups after raspberry supplementation, with enhanced benzoic acid derivatives when combined with fructo-oligosaccharides.

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2019·Phytotherapy research : PTR·Arrigo Francesco Giuseppe Cicero, Federica Fogacci, Marilisa Bove, et al

Three-arm, placebo-controlled, randomized clinical trial evaluating the metabolic effect of a combined nutraceutical containing a bergamot standardized flavonoid extract in dyslipidemic overweight subjects.

RCTn = 90Heart Health Inflammation Nutrition

Double-blind, placebo-controlled RCT tested a nutraceutical containing bergamot extract, phytosterols, vitamin C, and chlorogenic acid on 90 overweight dyslipidemic subjects. Active treatment groups showed significant improvements in triglycerides, LDL-C, and other metabolic markers compared to placebo. The nutraceutical improved lipid and glucose metabolism, adipokines pattern, and systemic inflammation.

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2019·The American journal of clinical nutrition·Geoffrey Istas, E. Wood, Melanie Le Sayec, et al

Effects of aronia berry (poly)phenols on vascular function and gut microbiota: a double-blind randomized controlled trial in adult men.

RCTn = 66Heart Health Gut Health

A double-blind, placebo-controlled RCT in 66 healthy men assessed the effects of aronia berry (poly)phenols on vascular function and gut microbiota. Aronia consumption improved endothelial function and modulated gut microbiota composition, suggesting potential cardiovascular health benefits.

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2018·The American journal of clinical nutrition·F. R. Baldrick, K. McFadden, M. Ibars, et al

Impact of a (poly)phenol-rich extract from the brown algae Ascophyllum nodosum on DNA damage and antioxidant activity in an overweight or obese population: a randomized controlled trial.

RCTn = 80Inflammation -

A randomized, double-blind, placebo-controlled crossover trial in 80 overweight or obese participants investigated the effects of a brown seaweed (Ascophyllum nodosum) polyphenol extract on DNA damage, oxidative stress, and inflammation. The study found a modest decrease in DNA damage only in the obese subset, with no significant changes in CRP, antioxidant status, or inflammatory cytokines.

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2014·Basic & clinical pharmacology & toxicology·Marina María de Jesús Romero-Prado, Jesús Aarón Curiel-Beltrán, María Viviana Miramontes-Espino, et al

Dietary flavonoids added to pharmacological antihypertensive therapy are effective in improving blood pressure.

RCTn = 79Heart Health Inflammation

An open-label, randomized, controlled trial evaluated the effect of adding dietary flavonoids to antihypertensive treatment in 79 hypertensive young patients. The combination of antihypertensive therapy and flavonoids significantly reduced blood pressure, triglyceride levels, leptin, and C-reactive protein plasma levels compared to antihypertensive therapy alone.

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2022·Journal of molecular modeling·Andrés Portilla-Martínez, Miguel Ortiz-Flores, Isabel Hidalgo, et al

In silico evaluation of flavonoids as potential inhibitors of SARS-CoV-2 main nonstructural proteins (Nsps)-amentoflavone as a multitarget candidate.

Study

In silico study evaluating 478 flavonoids against SARS-CoV-2 non-structural proteins using virtual screening. Amentoflavone, found in Ginkgo biloba and other plants, showed potential as a multitarget inhibitor of these proteins, suggesting its potential as a COVID-19 preventive or treatment.

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2020·Nutrition, metabolism, and cardiovascular diseases : NMCD·Vicente Agulló, Raúl Domínguez-Perles, Cristina García-Viguera

Sweetener influences plasma concentration of flavonoids in humans after an acute intake of a new (poly)phenol-rich beverage.

RCTn = 20

The study evaluated the plasma concentration of phenolic compounds after ingestion of a maqui-citrus-based beverage with different sweeteners (sucrose, stevia, sucralose) in 20 volunteers. Sucralose provided the greatest absorption value for most metabolites, suggesting it as a valuable alternative to sucrose to avoid metabolic disorders.

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2019·Current developments in nutrition·Laurel M. Wentz, D. Nieman, G. Valacchi, et al

Mixed Flavonoid Supplementation Attenuates Post-Exercise Plasma Levels of Protein Carbonyls and 4-Hydroxynonenal Protein Adducts Levels in Endurance Athletes (P23-009-19).

RCTn = 22Physical Performance Inflammation

Double-blinded, placebo-controlled, randomized crossover trial with 22 cyclists examining the effects of 2-week flavonoid supplementation on oxidative stress markers post-exercise. Flavonoid supplementation reduced plasma levels of 4HNE and protein carbonyls post-exercise, indicating decreased oxidative damage.

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2019·Nutrients·Miren Gómez-Juaristi, Beatriz Sarria, Sara Martínez-López, et al

Flavanol Bioavailability in Two Cocoa Products with Different Phenolic Content. A Comparative Study in Humans.

RCTn = 13

A crossover, randomized, blind study in 13 healthy men and women assessed the absorption and metabolism of flavanols in two cocoa products with different phenolic content. The study found that cocoa flavanols are moderately bioavailable and extensively metabolized, mainly by the colonic microbiota, with a dose-dependent absorption and a recovery of 35%.

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2015·Molecular nutrition & food research·Marta Farràs, Olga Castañer, Sandra Martín-Peláez, et al

Complementary phenol-enriched olive oil improves HDL characteristics in hypercholesterolemic subjects. A randomized, double-blind, crossover, controlled trial. The VOHF study.

RCTn = 33Heart Health

A randomized, double-blind, crossover, controlled trial with 33 hypercholesterolemic volunteers assessed the effects of functional virgin olive oils enriched with phenolic compounds on HDL functionality. The study found that FVOOT, enriched with olive oil phenolic compounds and thyme, improved HDL subclass distribution, composition, and antioxidant enzyme activities, suggesting potential benefits for managing high cardiovascular risk.

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2004·European journal of nutrition·Jaume Marrugat, María-Isabel Covas, Montserrat Fitó, et al

Effects of differing phenolic content in dietary olive oils on lipids and LDL oxidation--a randomized controlled trial.

RCTn = 30Heart Health

A randomized controlled trial with 30 healthy volunteers tested olive oils with varying phenolic content. Results showed increased urinary tyrosol and hydroxytyrosol, decreased plasma oxidized LDL, increased resistance of LDL to oxidation, and increased HDL cholesterol levels with higher phenolic content. Virgin olive oil with high phenolic content was more effective in protecting LDL from oxidation and raising HDL cholesterol levels.

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2025·International journal of molecular sciences·Jianqin Xu, Zhaowei Cai, Ziyao Pang, et al

Flavonoids Inhibit AMPK Activation and Induce Ferroptosis in Obesity-Associated Colorectal Cancer.

In vitro

The study investigated the antiproliferative effects of flavonoids (SGF) on obesity-related colorectal cancer using a murine colon adenocarcinoma MC38 cell line. SGF was shown to inhibit proliferation and migration of cancer cells, particularly in an adipocyte-rich environment, and exhibited stronger effects on MC38-transplanted tumors in obese mice. The study suggests that SGF induces ferroptosis and affects the AMPK pathway.

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2022·FASEB journal : official publication of the Federation of American Societies for Experimental Biology·Rían W Manville, Kaitlyn E Redford, Jennifer van der Horst, et al

KCNQ5 activation by tannins mediates vasorelaxant effects of barks used in Native American botanical medicine.

In vitroHeart Health

The study investigates the vasorelaxant effects of tannins from various barks used in Native American botanical medicine. Tannins, including gallic acid and tannic acid, were found to activate the KCNQ5 potassium channel, leading to vascular smooth muscle relaxation in rat mesenteric arteries.

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2026·Journal of inflammation research·Chenxi Wu, Xinru Xu, Yueyue Shi, et al

Standardized Extract of Flavonoids fromAlleviates Gouty Arthritis by Multi-Target Inhibition of Neutrophil Extracellular Traps via the Raf/ERK and Histone Citrullination Pathways.

Animal studyInflammation Joint Bone Health

The study investigates the effects of a standardized extract of flavonoids from Roxb. (SFSG) on gouty arthritis (GA) by targeting neutrophil extracellular traps (NETs) formation. SFSG treatment dose-dependently suppressed joint inflammation in a monosodium urate-induced GA model, reducing ankle swelling and inflammatory cytokines. In vitro, SFSG inhibited NETs formation and downregulated Raf/ERK signaling and CitH3 expression.

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2014·PLoS ONE·L. Theisen, C. Erdelmeier, Gilles A. Spoden, et al

Tannins from Hamamelis virginiana Bark Extract: Characterization and Improvement of the Antiviral Efficacy against Influenza A Virus and Human Papillomavirus

In vitro

The study characterizes tannins from Hamamelis virginiana bark extract and evaluates their antiviral efficacy against influenza A virus and human papillomavirus. It identifies a highly potent fraction enriched in high molecular weight condensed tannins that inhibits early and later steps in the IAV life cycle and HPV attachment.

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