All the Facts on Flavonoids
One reason fruits and vegetables are good for you is that they�re chock full of flavonoids, one of the most important categories of phytonutrients. Studies are beginning to show flavonoids� benefits in a big way:
So far, they�ve been linked to reduced risks of heart disease, Alzheimer�s disease, and cancer. I get plenty of these compounds from tea, vegetables, berries and other fruits, and dark chocolate, and I encourage you to do the same.
What they are. Flavonoids are divided into six types (see chart). Anthocyanins�the red, blue, and purple pigments in berries�have powerful cancer-protective effects. Some of the best-studied flavonoids are EGCG in green tea, the soy isoflavone genistein, and quercetin, found in apples and onions.
How they work. Flavonoids are strong antioxidants in test tubes, but their antioxidant activity in the body is weaker. Recent research suggests they may work instead by influencing gene expression and cell signaling pathways, both of which play a role in cancer and heart disease.
Who may benefit. Studies suggest dietary flavonoids can help ward off many age-related disorders.
Heart disease. When researchers analyzed dietary questionnaires from 34,489 postmenopausal women, two types of flavonoids�flavanones and anthocyanins�were associated with a reduced risk of death from coronary heart disease (American Journal of Clinical Nutrition, March 2007).
Cancer. In one study of almost 3,000 women, a diet rich in flavonoids cut the risk of breast cancer in postmenopausal women by about 35 percent (American Journal of Epidemiology, March 1, 2007). Research also shows that women whose diets contain the most kaempferol, a flavonol compound found in broccoli and tea, have a 40 percent lower risk of ovarian cancer.
Memory problems. A study of 1,640 seniors found that those with the highest flavonoid intakes experienced less cognitive decline over a 10-year period (American Journal of Epidemiology, June 15, 2007). Other studies have linked intake of flavonols and flavones to a reduced risk of age-related dementia.
How to maximize the benefits. Opt for organic produce, which some reports suggest has higher levels of flavonoids than conventional-grown varieties. And steam your vegetables rather than boil them to retain more of these healthful substances.
FLAVONOID TYPE AND FOOD SOURCES
Anthocyanins
Black, blue, & red berries, red & purple grapes, red wine
Flavanols
Green tea, chocolate, apples, apricots, red grapes, red wine
Flavanones
Citrus fruits and juices, e.g., oranges, grapefruits, lemons
Flavonols
Onions, kale, leeks, broccoli, apples, blueberries, cranberries
Flavones
Parsley, thyme, celery, hot peppers
Isoflavones
Soybeans, soy foods, legumes
Sources: Linus Pauling Institute; Jeffrey Blumberg, PhD
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Dr. Weil - The Facts on Flavonoids
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