Bioflavonoids What do they do? Bioflavonoids are a class of water-soluble plant pigments. While they are not considered essential, they do support health as anti-inflammatory, antihistaminic, and anti-viral agents. They block the “sorbitol pathway” that is linked to many symptoms of diabetes. Bioflavonoids also protect blood vessels and reduce platelet aggregation (acting as natural blood thinners).
As antioxidants, some bioflavonoids, such as quercetin, protect LDL-cholesterol from oxidative damage. Others, such as the anthocyanidins from bilberry, may help protect the lens of the eye from cataracts. Preliminary evidence suggests that some bioflavonoids, such as naringenin, may have anticancer activity.
Where are they found? Bioflavonoids are found in a wide range of foods. For example, citrus flavonoids are found in citrus fruits, rutin in buckwheat, epigallocatechin gallate (EGCG) in green tea, anthocyanidins in bilberry, and naringenin in grapefruit. In addition, OPCs, or oligomeric proanthocyanidins, are found in grape seeds and skins, and quercetin is found in many foods, including onions, tea, and apples.
In what conditions might bioflavonoids be supportive?
• atherosclerosis (quercetin, bilberry) • capillary fragility (quercetin, rutin, hesperidin)
• cataracts (quercetin, bilberry)
• circulation (bilberry)
• chronic venous insufficiency (hydroxyethylrutosides)
• diabetes (quercetin, bilberry)
• edema (water retention) (quercetin, rutin)
• gingivitis (periodontal disease)
• glaucoma (rutin)
• hay fever (quercetin, hesperidin, rutin) • hepatitis (catechin, silymarin)
• high cholesterol (quercetin)
• macular degeneration (bilberry)
• menopause (hesperidin)
• menorrhagia (heavy menstruation)
• retinopathy (bilberry)
Who is likely to be deficient? Bioflavonoid deficiencies have not been reported.
How much should I take? Although bioflavonoid supplements are not required to prevent deficiencies in individuals eating a healthy diet, doctors of natural medicine often recommend 1,000 mg of citrus bioflavonoids or 400 mg of quercetin, each taken three times per day.
Are there any side effects or interactions? No consistent toxicity has been linked to the bioflavonoids. The exception is for a bioflavonoid called cianidanol, which is not found in supplements.
The bioflavonoids help protect vitamin C; the citrus bioflavonoids, in particular, improve the absorption of vitamin C.1 2
References:
1. Vinson JA, Bose P. Comparative bioavailability to humans of ascorbic acid alone or in a citrus extract. Am J Clin Nutr 1988;48:601-4.
2. Vinson JA, Bose P. Comparative bioavailability of synthetic and natural vitamin C in Guinea pigs. Nutr Rep Intl 1983;27 (4):875.
Copyright © 1998 Virtual Health, LLC
It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over-the-counter medication is also available. Consult your physician, nutritionally-oriented health care practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications.The information presented in HealthNotes Online is for informational purposes only.