Flavonoids

What are flavonoids?

Flavonoids are polyphenols found in plant foods. They are natural pigments, which give yellow, red or blue color to fruits and vegetables.

Flavonoids in Foods

Naturally occurring flavonoids (except catechins and proanthocyanidins) are connected to one or more sugar molecules–in this form they are called flavonoid glycosides; when they are not connected to sugars, they are called aglycones. For example, hesperidin is a glycoside (with sugar) and hesperitin is an aglycone (without sugar).

FLAVONOID SUBCLASS	FLAVONOID	FOODS HIGH IN FLAVONOIDS
Anthocyanidins	Cyanidin, delphinidin, malvidin, pelargonidin, peonidin, petunidin	Red, blue, and purple berries; red and purple grapes; red wine
Flavanols	Catechin, epicatechin, epicatechin gallate, epigallocatechin, epigallocatechin gallate	Yod kratin (a Thai vegetable), green tea, white tea, chocolate, grapes, berries, apples
	Theaflavins, thearubigins	Black tea, oolong tea
	Proanthocyanidins or condensed tannins or flavolans or flavan-3-ols	Chocolate, apples, berries, red grapes, red wine, maritime pine bark, cinnamon, aronia (chokeberry), grape seeds
Flavanones	Hesperetin, naringenin, eriodictyol	Oranges, grapefruits, lemons and their juices
Flavonols	Quercetin, kaempferol, myricetin, isorhamnetin	Yellow onions, scallions, kale, broccoli, apples, berries, Ginkgo biloba, teas
Flavones	Apigenin, luteolin, nobiletin, sinensetin, tageretin	Parsley, thyme, celery, hot peppers
Isoflavones	Daidzein, genistein, glycitein	Soybeans, soy products, legumes

Flavonoids Supplements

Flavonoids Health Benefits

There is INSUFFICIENT EVIDENCE about the effectiveness of high flavonoid intake from foods on the prevention or treatment of colorectal cancer or as antioxidants ^[1,3].

According to one 2002 cohort study in Finland ^[2]:

High quercetin intake (mainly from apples and onions) was associated with lower asthma incidence and lower mortality from ischemic heart disease in general population, and in lower incidence of lung cancer in men.
High hesperitin intake (mainly from citrus fruits) was associated with lower incidence of asthma, cerebrovascular disease.

NOTE: The study results do not mean that quercetin or hesperitin actually prevent any disease.

In various studies, green tea polyphenols, catechins, and genistein supplements were associated with better protection against sun ^[1].

Flavonoids Linus Pauling Institute
Knekt P et al, 2002, Flavonoid intake and risk of chronic diseases The American Journal Of Clinical Nutrition
Jin H et al, 2012, Dietary flavonoid for preventing colorectal neoplasms Cochrane