Flavonoid Ranking Table

There is no official recommended daily intake for flavonoids. Studies showing health benefits typically involve intakes of 200–500 mg of total flavonoids per day from food. A single cup of green tea provides roughly 150–250 mg of catechins; a 100g serving of blueberries provides 150–400 mg of mixed flavonoids. Eating a varied diet with fruits, vegetables, legumes, and whole grains across the day — rather than targeting one number — is the most practical approach to consistent flavonoid intake.

Flavonoids are divided into six major classes: flavonols (quercetin, kaempferol — found in onions, kale, apples, capers), flavanols (catechins, EGCG — found in green tea, cocoa, berries), anthocyanidins (cyanidin, delphinidin — in blueberries, red cabbage, cherries), flavanones (hesperidin, naringenin — in citrus), flavones (luteolin, apigenin — in parsley, celery), and isoflavones (daidzein, genistein — in soy). Each class has distinct biological properties and food sources.

It depends on the class. Quercetin (a flavonol) is relatively heat-stable and survives cooking in onions fairly well. Anthocyanidins (in berries) are more sensitive to heat and oxidation — cooking reduces them significantly. Catechins (in tea) are largely retained when brewed but degraded by prolonged boiling or high-temperature processing. Fermentation transforms flavonoid profiles substantially, as in soy products. In general, gentle steaming or light cooking causes less loss than long boiling.