TABLE 1.

Flavonoid classes, compounds, and sources

	Respective compounds	Common plant sources
Flavonoid class
Anthocyanidins	Cyanidin, delphinidin, malvidin, pelargonidin, peonidin, petunidin	Blueberries, red wine, strawberries
Flavan-3-ols	Epicatechin, epicatechin 3-gallate, epigallocatechin, epigallocatechin gallate, catechin, gallocatechin	Apples, black tea, blueberries, chocolate, red wine
Flavanones	Eriodictyol, hesperetin, naringenin	Citrus fruit and juices, herbal tea
Flavones	Apigenin, luteolin	Celery, garlic, green peppers, herbal tea
Flavonols	Isorhamnetin, kaempferol, myricetin, quercetin	Blueberries, garlic, kale, onions, spinach, tea, broccoli, red wine, cherry tomatoes
Proanthocyanidins	Monomers, dimers, trimers, 4–6mers, 7–10mers, polymers	Apples, black tea, blueberries, chocolate, mixed nuts, peanuts, red wine, strawberries, walnuts
Isoflavones	Daidzein, genistein, glycitein, coumestrol, formononetin, biochanin A	Soy products, peanuts
Total flavonoids
>50 mg/100 g		Apples, black tea, blueberries, chocolate, garlic powder, grapefruits, grapes, herbal tea, mixed nuts, oranges, pears, red wine, strawberries, walnuts
>50 mg/serving1		Apples, black tea, blueberries, chocolate, grapefruit juice, grapefruit, grapes, herbal tea, oranges, pears, red wine, strawberries

¹Serving sizes that are predefined on the food-frequency questionnaire are available from www.cancer.org and are generally similar to those of the USDA Nutrient Database for Common Reference (http://www.ars.usda.gov).