Flavonoid

PhytochemicalBest with a meal

What is it

Flavonoid is the singular term for a member of the flavonoid family of plant polyphenols. The family includes flavones, flavonols, flavanones, flavan-3-ols, anthocyanins, and isoflavones.

Evidence for 2 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Cardiovascular health (dietary intake)

Good Evidence

Cohort studies consistently link flavonoid-rich diets with lower CVD risk.

Antioxidant biomarkers

Limited Evidence

Short-term human studies show effects on oxidative stress markers.

How it works

Flavonoids act as antioxidants, modulators of cell-signaling (NF-kB, Nrf2), inhibitors of platelet aggregation, and supporters of endothelial nitric oxide. Most are poorly absorbed in their original form; gut bacteria metabolize them into smaller phenolics that account for many measurable systemic effects. Habitual dietary intake correlates with lower cardiovascular and metabolic risk in cohort studies.

Dosage

No RDA. Typical Western intake is 200-600 mg/day. Targeted single-flavonoid supplements (quercetin, hesperidin, EGCG) range from 200 to 1000 mg/day.

When and how to take it

Take with meals; many flavonoids benefit from fat or food matrix for absorption.

2 commercial forms

Compare the main delivery options and what they’re best suited for.

Whole-food flavonoids

Tea, berries, citrus, onions, cocoa.

Matrix effects; gut microbiota-dependent.

Standardized extracts

Allow defined dosing of single compounds.

Higher per-dose; variable absorption.

Safety

Safe from food sources. Concentrated supplements may interact with drugs or cause GI upset at high doses.

Who should be cautious

People on narrow-therapeutic-index medications should check with a pharmacist before high-dose flavonoid supplements.

Interactions

Some flavonoids inhibit CYP3A4 and P-glycoprotein, affecting drug levels. Notable example: grapefruit furanocoumarins (not strictly flavonoids) and high-dose quercetin.

Food sources

Tea (1 cup)

Amount
100-200 mg flavanols
%DV
—

Berries (1 cup)

Amount
100-300 mg mixed flavonoids
%DV
—

Dark chocolate (1 oz, >70%)

Amount
~50-100 mg flavanols
%DV
—

Frequently asked questions

Should I eat more flavonoids?⌄

Yes, via food. Tea, berries, citrus, onions, apples, and cocoa are good sources.

Are flavonoids essential?⌄

No. They are bioactive phytochemicals associated with health benefits, but not essential nutrients.

References

Flavonoid on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Flavonoid (PubMed search) — PubMed link

Track Flavonoid with Pilora

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.