Flavonoids, of which there are over 4,000, are plant pigments which provide color to many fruits and flowers. They have anti-allergic, anti-inflammatory, antiviral, and anticarcinogenic properties.
Flavonoids are of great importance because of their antioxidant functions. A 1993 study reported a high intake of flavonoids was associated with a decrease in fatal heart attacks.1 When heart attacks did occur, flavonoid levels were low. It is speculated that they protect the heart by preventing cholesterol oxidation. Flavonoids are believed to be even more powerful antioxidants than Vitamin C, Vitamin E, selenium, and zinc.2
Catechins are naturally occurring flavonoids containing some of the properties of silymarin and lipoic acid. As an antioxidant, they inhibit free radical oxidative damage.
Red wine and the skins and seeds of red grapes contain flavonoid compounds which contribute to good health. These flavonoids include catechins, proanthocyanidins, and anthocyanidins. Younger red wines will have more flavonoids. White wines have very few. There are supplements similar to Pycnogenol made with grape extract rather than pine bark. Studies have indicated that certain components of red wine appear to offer protection from heart disease by increasing the good HDL cholesterol. These compounds (the polyphenols and flavonoids) also reduce the chances of blood clots.
Green tea contains good amounts of Vitamins C, E, minerals, polyphenols, and flavonoids (catechin epigallocatechin gallate-EGCG). Green tea polyphenols are hailed for their antioxidant functions. They are thought to increase antioxidant functions of other enzymes as well. A clinical study with human subjects confirmed the role of this flavonoid in cancer prevention. It has shown most beneficial in gastrointestinal cancers, and cancers of the lung and breast. A 1993 study reported the action of green tea polyphenols in inhibiting carcinogenic nitrosamines when taken with meals. The common consumption of green tea with meals in Japan has been linked to a much lower cancer rate in this country. Green teas are thought to have little to no side effects.
Research indicates green tea kills viruses and bacteria and acts as an immunity booster and antioxidant. There is speculation that green tea may be a potential treatment for cancer, heart disease, and dental cavities. In addition to tea form, there are green tea extracts in capsule form. Results from animal studies indicate that green tea can prevent skin cancer. There is also some evidence that the compounds in this supplement protect against lung, liver, pancreatic, and stomach cancer. The benefits of green tea in heart disease have also been noted. One study found that Japanese women who drank at least five cups of green tea a day lowered their risk of stroke by half. Other studies indicate that green tea can lower cholesterol and blood pressure. In addition to its benefits against degenerative disease, green tea has also been utilized as a weight loss aid.
Quercetin is the most active flavonoid group in experimental studies. Quercetin acts as an antiviral, anti-inflammatory, antioxidant, and a Vitamin C preserver. Its anti-inflammatory and anti-allergic properties make it beneficial for arthritis and hayfever.
Quercetin offers relief for diabetics by inhibiting the enzyme aldose reductase. This enzyme converts glucose to sorbitol, which is associated with several diabetic complications. Also important for diabetics is quercetinÕs ability to enhance insulin secretion, ward off free radical activity in pancreatic cells, and obstruct platelet aggregation.
Quercetin prevents the buildup of sorbitol in the lens of the eye, there by delaying the development of cataracts. The antitumor effect of quercetin is perhaps its greatest function. Though only tested in animals and in in vitro studies, quercetin has been shown to be active against many types of cancers. Researchers have also found quercetin inhibits DNA synthesis in leukemia cells. It was found to be dose related Ñ the higher the dose of quercetin, the more leukemia-cell DNA synthesis was slowed. After two or three days, high doses completely inhibited DNA synthesis. DNA synthesis resumed in the cells after quercetin was removed.
Citrus bioflavonoids include rutins, hesperidin, quercetin, and naringin. These are the most used and least expensive of flavonoid preparations. However, they are also the least active. Citrus bioflavonoids are needed for the proper absorption and use of Vitamin C. They have been successful in the treatment of capillary permeability, easy bruising, hemorrhoids, hypertension, and varicose veins.
Proanthocyanidins (PCOs) are among the several groupings of flavonoids. PCOs are found in many plants and red wine. Commercially these flavonoids are available as grape seed extract and pine bark extract. PCOs are beneficial for increasing intracellular levels of Vitamin C, protecting the integrity of capillaries and collagen, and working as an antioxidant. Research from 1993 indicates these flavonoids inhibit substances such as histamines which cause inflammation and allergies. In addition to use in vein and capillary disorders, PCOs are also indicated in retinal disorders. A 1988 study conducted on humans found grape seed extract improves visual function in healthy subjects.
Hawthorn (Cratageus oxyacantha) is a native European plant. It contains polyphenols and the flavonoids quercetin, vitexin, catechin. Research indicates that this herb lowers cholesterol and blood pressure, and can help prevent heart palpitations and arrhythmias. Because it has such effects on the heart, it is advisable to use only under a physicianÕs supervision.
Pycnogenolª is a trademark for a blend of nutrients extracted from the bark of the coastal pine tree Pinus maritima, which is native to France. The bark is rich in flavonoids, particularly the proanthocyanidins. It has proven to be a powerful antioxidantÑmore powerful than Vitamin E and Vitamin CÑin fat and water-based surroundings.
Pycnogenol does more than protect. It also helps repair. It can strengthen blood vessels and reduce vascular fragility, improve circulation and vision, improve skin smoothness and elasticity, improve joint flexibility and fight inflammation. Because of its antioxidant properties, it is used to prevent of cancer, heart disease, and other degenerative conditions. The collagen-rich connective tissue in artery walls is protected and stimulated for repair by Pycnogenol, which in part helps protect against early atherosclerosis. It also reduces histamine production, thereby helping artery linings resist attack by mutagens, free radicals and oxidized LDL-cholesterol.
Healthy brain cells are important for memory and stroke prevention. Strengthened capillaries help protect against stroke. Besides protecting and strengthening blood vessels, Pycnogenol is able to cross the blood-brain barrier to protect the brain from free radicals. This protection will help memory and reduce senility. It appears even sluggish memories are improved perhaps due to better circulation and cell nourishment.
Researchers at the Second International Pycnogenol Symposium, held in May 1995, reported the effective use of the supplement in attention deficit disorder (ADD). Many patients formerly on Ritalin have switched to Pycnogenol and had much success.
Milk thistle (Silybum marianum) is a very popular supplement in Europe, particularly Germany. The standardized extract silymarin contains flavonoids which provide special protection to the liver. Milk thistle acts as an antioxidant which encourages the regeneration of liver cells and enhances the ability of this organ to filter toxins from the blood.5 This supplement is used in the prevention and treatment of toxin exposure (food poisoning, industrial chemicals, radiation, alcohol and drug poisoning).6 It is also used as a general immune stimulant.
Soy foods contain two particularly beneficial isoflavones, genistein and daidzein. These isoflavones have notable implications in the prevention of various cancers and heart disease. Studies also point to isoflavones as effective hormone balancers in women and potential prevention against osteoporosis.
Genistein and daidzein work as antioxidants, inhibiting the free radicals responsible for the development of cancer and heart disease. These compounds contribute to a healthy heart by preventing the causal factors of atherosclerosis such as reducing platelet aggregation and plaque formation, lowering cholesterol levels and improving artery elasticity. Populations with a higher consumption of soy foods have been found to have a lower risk of breast, colon, and prostate cancer, and cardiovascular disease rates than those with less soy in the diet.
Phytoestrogens have the ability to bind to estrogen receptors of cells in the body, and block some of the human estrogen circulating in the body from getting to these cells. Blocking estrogen, and thus lowering estrogen levels, may reduce side effects or toxicity of excessive estrogen levels on the body. These isoflavones are thought to be effective against breast cancer because they can also attach to estrogen-receptive tumors and prevent their growth.
Last but not least, rutin is a flavonoid which improves circulation in the lower limbs. It has been used in treating varicose veins and hemorrhoids.
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