Foods High in Polyphenols: Classes, Sources and USDA Data

Foods high in polyphenols include spices and dried herbs, cocoa products, darkly coloured berries, seeds such as flaxseed, nuts such as chestnuts and hazelnuts, and vegetables such as olives and globe artichokes. That list comes from a 2010 analysis of the Phenol-Explorer database, which compiled published measurements for 452 foods. USDA SR Legacy, the database behind most of our food tables, has no polyphenol values, so this guide uses the Phenol-Explorer papers and the separate USDA Flavonoid Database exactly as published. Below are the four main classes, the richest food groups, a USDA flavonoid table, and the reasons the numbers vary.

Peptide Labs does not sell the foods in this list. This article is about food, and it is general nutrition information, not medical advice.

What are polyphenols?

Polyphenols are compounds that plants make as secondary metabolites. A 2009 review (Pandey and Rizvi) explains that plants generally use them for defense against ultraviolet radiation and pathogens, and that in food they contribute to bitterness, astringency, color and flavor. The same review notes that more than 8,000 polyphenolic compounds have been identified, and that the outer layers of plants hold more of them than the inner parts.

Because the family is so large, there is no single lab number for polyphenols in a food. The Phenol-Explorer team summed the individual compounds measured by chromatography. Their 2010 paper reports that a common colorimetric test, the Folin assay, systematically gave higher totals than that sum, which is one reason figures from different sources disagree.

Types of polyphenols: the four main classes

Class (Pandey and Rizvi 2009)	Subgroups or examples	Food sources named in the review
Flavonoids	Six subclasses: flavonols, flavones, flavanones, flavanols, anthocyanins and isoflavones	Quercetin, a flavonol, is found across fruit, vegetables, cereals, tea and wine; flavanones and isoflavones are specific to particular foods
Phenolic acids	Derivatives of benzoic acid and of cinnamic acid (such as caffeic and ferulic acids)	Found abundantly in foods; benzoic types are low except in certain red fruits, black radish and onions
Stilbenes	Resveratrol is the most studied	Low in the diet overall; found largely in grapes and red wine
Lignans	Secoisolariciresinol and matairesinol	Linseed (flaxseed) is the richest dietary source

Flavonoids are the most studied class. The 2009 review counts more than 4,000 varieties, many of them responsible for the colors of flowers, fruits and leaves. Our resveratrol guide and flaxseed guide go deeper on the two smaller classes.

Foods high in polyphenols by food group

The 2010 Phenol-Explorer analysis produced a list of the 100 richest sources among 452 foods. Its summary gives the range, from 15,000 milligrams per 100 grams in cloves down to 10 milligrams per 100 milliliters in rose wine (Phenol-Explorer, 2010), and names the leading groups. We read the published summary, not the full ranked table, so the groups below are not ranked against each other.

Spices and dried herbs

Spices and dried herbs head the Phenol-Explorer summary, with cloves at the top of the range. They are used in pinches, so a high concentration does not mean a large amount on the plate. Fresh herbs can be concentrated too: USDA lists fresh parsley at about 215 milligrams of the flavone apigenin per 100 grams.

Cocoa products

Cocoa products are the second group named. In USDA flavonoid data, unsweetened cocoa powder averages about 196 milligrams of epicatechin per 100 grams, while cocoa processed with alkali averages about 57 milligrams. Our chocolate guide and cacao guide cover calories, sugar and caffeine.

Dark berries and other fruit

Darkly coloured berries owe their color to anthocyanins, a flavonoid subclass. USDA lists raw blackberries at about 100 milligrams of cyanidin per 100 grams and cultivated blueberries at about 68 milligrams of malvidin. Sweet cherries, strawberries, oranges and apples appear lower in the USDA table below. In a French cohort study that used Phenol-Explorer, fruit and non-alcoholic beverages were the largest contributors to polyphenol intake (Perez-Jimenez 2011).

Seeds and nuts

The Phenol-Explorer summary singles out flaxseed among seeds and chestnuts and hazelnuts among nuts. Flaxseed is also the richest dietary source of lignans in the 2009 review.

Vegetables

Olives and globe artichoke heads are the vegetables named in the Phenol-Explorer summary. In the USDA flavonoid data, raw red cabbage, kale and red onions are among the everyday vegetables in the table below.

Tea and other drinks

Tea supplies flavan-3-ols, often called catechins. USDA lists brewed black tea at about 9 milligrams of one catechin, epigallocatechin 3-gallate, per 100 grams of a standard 1% infusion, and notes that brewing habits differ so much between countries that tea values are hard to compare. Our green tea guide and black tea guide cover caffeine and brewing.

Polyphenol foods list: USDA flavonoid values

The USDA Database for the Flavonoid Content of Selected Foods (Release 3.3, 2018) covers 506 foods and 26 flavonoids in five subclasses. It leaves out isoflavones and proanthocyanidins, which USDA publishes separately, and it does not cover phenolic acids, stilbenes or lignans. Each row shows one of the flavonoids USDA lists for that food, as a mean per 100 grams of edible portion, so the table is a sample of the data and not a total polyphenol ranking.

Food (USDA NDB No.)	Flavonoid shown	Subclass	Mean per 100 g (USDA Flavonoid Database)
Parsley, fresh (11297)	Apigenin	Flavones	215.46 mg
Red cabbage, raw (11112)	Cyanidin	Anthocyanidins	209.83 mg
Cocoa powder, unsweetened (19165)	Epicatechin	Flavan-3-ols	196.43 mg
Capers, canned (02054)	Quercetin	Flavonols	172.55 mg
Blackberries, raw (09042)	Cyanidin	Anthocyanidins	99.95 mg
Blueberries, cultivated, raw (09050)	Malvidin	Anthocyanidins	67.59 mg
Cocoa powder, processed with alkali (19166)	Epicatechin	Flavan-3-ols	56.60 mg
Kale, raw (11233)	Kaempferol	Flavonols	46.80 mg
Onions, red, raw (99055)	Quercetin	Flavonols	39.21 mg
Cherries, sweet, raw (09070)	Cyanidin	Anthocyanidins	30.21 mg
Oranges, raw (09200)	Hesperetin	Flavanones	27.25 mg
Strawberries, raw (09316)	Pelargonidin	Anthocyanidins	24.85 mg
Onions, raw (11282)	Quercetin	Flavonols	20.30 mg
Black tea, brewed (14355)	Epigallocatechin 3-gallate	Flavan-3-ols	9.36 mg
Apples, raw, with skin (09003)	Epicatechin	Flavan-3-ols	7.53 mg

The means hide wide ranges. In the same USDA database, individual onion samples ran from 1.50 to 90.75 milligrams of quercetin per 100 grams, and red cabbage samples from 7.36 to 475.08 milligrams of cyanidin.

Why polyphenol content varies

• Ripeness: the 2009 review reports that phenolic acids generally fall during ripening while anthocyanins rise.
• Growing conditions: soil type, sun exposure and rainfall all change content, per the same review.
• Storage: a 2015 analysis of Phenol-Explorer data found small losses in storage, with typical retention of about 88% at room temperature, 95% refrigerated and 92% frozen (Phenol-Explorer, 2015).
• Cooking: the same analysis found that home cooking of common plant foods caused considerable losses, with typical retention of 45% to 70% and high variability (Phenol-Explorer, 2015). The 2009 review cites a study in which onions and tomatoes lost 75% to 80% of their quercetin after 15 minutes of boiling and about 30% after frying (Pandey and Rizvi 2009).
• Processing: alkali-processed cocoa averages well under a third of the epicatechin of natural cocoa in the USDA table above.

Content is not the same as absorption

A high number in a table does not tell you how much reaches the bloodstream. The 2009 review explains that most polyphenols occur in food as esters, glycosides or polymers that cannot be absorbed in that form, and that the compounds are extensively modified in the intestine and liver. A 2004 review in the American Journal of Clinical Nutrition reached the same conclusion: bioavailability differs greatly from one polyphenol to another, and the most abundant ones in the diet are not necessarily the most readily absorbed.

Research on polyphenols and long-term health is ongoing, and this guide makes no claims about it. Polyphenols overlap with the vitamins and carotenoids covered in our antioxidant food chart, which uses USDA nutrient values. The sister guide on foods high in resistant starch covers another food component that SR Legacy does not report.

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Last reviewed October 2026.

Related guides: Foods High in Resistant Starch: Types and Measured Values, Foods High in Antioxidants: USDA Chart and What the Science Says, Green Tea Benefits: What the Research Shows, Caffeine and Side Effects, Foods High in Flavonoids: USDA Database Values by Subclass.