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Flavonoids and bioflavonoids

Citrus fruits

Flavonoids and bioflavonoids are often confused as being the same and are found in the same types of fruit, plants and vegetables, however, they do have distinctively different chemical bonds. This being said, they do provide some of the same health benefits in the human body such as dilating and strengthening the blood vessels and keeping them elastic and flexible. They also both strengthen the bones and collagen which is the connective tissues in the body. Vitamin C is required for these  actions to take place and, fortunately, is present in the same natural foods that contain flavonoids and bioflavonoids.

They are broken down into flavones, isoflavonoids, and neoflavonoids initially. Each of these categories can be broken down further.

All these compounds have ketone groups, which are oxygen atoms double-bonded (indicated by an O connected by two lines) to a carbon that is not at the end of a chain, and somewhere in the middle of the structure. If a molecule loses its ketone group, its name gets an A in place of an O. For example, flavonoid turns into flavanoid, and flavonol turns into flavanol.

If a bioflavonoid has a 5-carbon ring in the centre rather than the typical 6-carbon ring structure, it is known as an aurone.

Because they have all been named so similarly they are constantly confused and misspelt. Common misspellings for bioflavonoids include bioflavinoids, bioflavanoids, flavinoids, flavanoids, falvanoids, falvinoids, bioflavanoid).


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Flavonoids are a plant pigment that is found in many fruits and flowers. The common colours for these pigments are blue, purple, red and yellow. The pigments are found in the cytoplasm and plastids of flowering plants. As opposed to other pigments such as betalains, chlorophylls or carotenoids, certain flavonoids play a role in fruit ripening and capturing certain variants of light within the UV spectrum.

A large number of phytonutrients fall into the flavonoid category. They reduce people's risk of asthma, certain types of cancer and coronary heart disease.

Flavonoids, including apigenin, prevent in vitro LDL oxidation which can help to prevent atherosclerosis.

Natural sources of flavonoids



Bioflavonoids are polyphenolic compounds found in plants. There are over 5,000 bioflavonoids identified throughout the plant kingdom, many of which have been the subject of preclinical and human research. Bioflavonoids have been widely recognised to affect a wide range of systems in the body. Previously known as vitamin P, bioflavonoids are water-soluble and found as a crystalline substance especially in citrus juices. The term bioflavonoids refers to many different substances.

Bioflavonoid list

  • Cynaroside

  • Diosmin

  • Eriodictyol

  • Hesperin

  • Hesperidin

  • Luteolin

  • Oxerutins

  • Quercetin

  • Quercertrin

  • Rutin

  • Silymarin

Bioflavonoids cannot be manufactured by the body and must be supplied in the diet. The major flavonoids found in citrus fruits, diosmin, hesperidin and oxerutins, appear to be very beneficial.

Bioflavonoids have an antibacterial effect and promote circulation. They are also useful for lowering blood cholesterol levels and in the prevention and treatment of cataracts. They are vital in their ability to increase the strength of the capillaries (blood vessels) and to regulate their permeability and for this reason are good additions to the diet for those prone to having a stroke.

Other benefit of bioflavonoids are the ability to reduce inflammation and help the body get rid of potentially toxic and cancer-causing chemicals which can be advantageous to those with Alzheimer's and Parkinson's disease and similar inflammatory conditions.

Bioflavonoids enhance the action of vitamin C and prolong the effectiveness of it so, for this reason, they should always be taken together and most natural foods that provide vitamin C also provide bioflavonoids/ They work together to help maintain the thin walls of the capillaries, therefore preventing bleeding or bruising. They assist vitamin C in keeping collagen, the intercellular "cement" in healthy condition; are essential for the proper absorption and use of vitamin C and prevents vitamin C from being destroyed in the body by oxidation. They are beneficial in hypertension; help to heal ruptures in connective tissues and they can help to build a protective barrier against infections. Quercetin is a very highly concentrated form of bioflavonoids derived from citrus fruits.

Bioflavonoids are effectively used in the treatment of sport injuries as they also have pain relieving properties. They can be used to relieve back pain and pains in the legs and can lessen the symptoms of prolonged bleeding such as a low serum calcium.

Bioflavonoids have an antibacterial effect, stimulate bile production, improve circulation and even assist with fighting allergies, asthma and oral herpes (cold sores) etc.

Deficiency of bioflavonoids

If a diet contains enough fruits and vegetables, bioflavonoids should not be deficient, but deficiency would show up as bruising. Bioflavonoids could be of help in iron deficiency (anaemia), as well as where antioxidants are indicated and none present, since it helps with the absorption of iron.

Absorption of the bioflavonoids can be a bit slow, but small amounts can be stored in the body. If suffering from herpes, foods rich in vitamin C and bioflavonoids, consumed three times a day at least, will help and can prevent cold sores.

Natural sources of bioflavonoids

NOTE: In citrus fruits, bioflavonoids are found in the white pith material just beneath citrus peel.

CAUTION: Components of the grapefruit can influence the function of certain enzymes along the gastrointestinal tract or in the liver, and these interactions influence the rate at which certain medications can be broken down or removed from the body. Much of the past attention had focused on felodipine (marketed as Plendil), a popular medication for treating hypertension. When this occurs, the level of the blood pressure lowering medication in the body becomes too high, by as much as a five-fold increase. Thus, blood pressure may fall too low, causing symptoms of light-headedness, dizziness, weakness or even fainting. It does not take much grapefruit or grapefruit juice to make this happen, especially if it is consumed on a regular basis. There is great individual variability, however, on who will and who will not be reactors.

Another group of medications that interact with the grapefruit are the “statins,” which are now widely prescribed to lower blood cholesterol levels. There are many other medications, however, that also interact with grapefruits. A partial list (using drug generic names) includes the following:

  • Alprazolam

  • Aorvastatin

  • Benzodiazepines

  • Buspirone

  • Carvediol

  • Cerivastatin

  • Cisapride

  • Clomipramine

  • Coumadin

  • Cyclosporine

  • Ethinyl

  • Estradiol

  • Felodipine

  • Lovastatin

  • Nifedipine

  • Nimodipine

  • Saquinavir

  • Simvastatin

  • Tacrolimus

  • Testosterone

  • Triazolam

See more about individual bioflavonoids and associated nutrients

Health issues flavonoids and bioflavonoids can treat and protect against


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"Nature cures not the physician..." Hippocrates 460 BC


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