Bioflavonoids are natural plant compounds that comprise the pigments responsible for the bright colors of fruits and vegetables. Researchers have isolated more than 4,000 different bioflavonoids, which may be divided into four broad categories. The richest dietary sources of these plant pigments include green tea, berries, red wine, citrus fruits, parsley, onions, and legumes. Scientists credit bioflavonoids with many beneficial health effects, including lowering cholesterol, strengthening blood vessels, and enhancing the body's ability to deal with viruses, carcinogens, and allergens. The compounds also possess powerful antioxidant or anti-aging properties, defending the body from the deleterious effects of pollutants, free radicals, and other toxins.
The quercetins are the most active of the flavonoids, possessing anti-viral, antioxidant, and anti-inflammatory effects. Quercetins are helpful with practically every allergic and inflammatory disease, including hay fever, asthma, rheumatoid arthritis, and lupus. They help to prevent diabetes-related retinopathy and cataracts, as well as amplify insulin secretion. Also, they inhibit herpes simplex, polio, influenza, and cold viruses. The standard dose range is from 200 to 400 milligrams three times daily about 20 minutes before meals.
Steaming the freshly cut leaves of the camellia sinensis plant produces green tea polyphenols. Polyphenols have potent antioxidant and anticancer effects, suppressing activation of cancer-causing agents that contribute to lung cancer, breast cancer, and colon cancer. One cup of green tea contains approximately 300 to 400 milligrams of the polyphenols, which is the recommended dose. The drawback to green tea is the 50 to 100 milligrams of caffeine found in every cup. Commercially available concentrated decaffeinated green teas contain 60 to 80 percent polyphenols.
The most commonly occurring bioflavonoids are the proanthocyanidins. These antioxidants fend off chronic degenerative conditions, such as arthritis and heart disease, and prevent free radical injury that leads to aging. They lower blood cholesterol levels, treat varicose veins, prevent easy bruising, and inhibit formation of dangerous cholesterol plaques and blood clots. Approximately 50 milligrams per day of grape seed extract and pine bark extract, containing 80 to 95 percent proanthocyanidins, delivers the recommended dose for prevention of disease. For treatment of medical conditions, a dose of 150 to 300 milligrams daily of either extract is effective.
Citrus bioflavonoids, including quercitrin, hesperidin, naringen, and rutin, have yielded promising results in treating hemorrhoids, varicose veins, and excessive bruising. Mixed formulas provide the standard dose of 2,000 to 6,000 milligrams daily. Although generally safe, products containing naringen, found in grapefruit, can strengthen the drug effects of nifedipine, verapamil, and terfenadine. They also prolong the effects of caffeine, estrogens, and blood thinners.
Bioflavonoids are not considered necessary for life, Studies indicate, however, that their invaluable health advantages can improve quality of life. A wide variety of bioflavonoids can be incorporated into the diet by eating a range of colorful fruits and vegetables each day.