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What do citrus fruits, grape seed extract, red wine, pine
bark extract, and onions have in common? The answer is they’re
alt good sources of flavonoids, the plant pigments that help
fight a host of disorders, from cataracts and cancer to hay
fever and menopausal hot flashes.
What Is It
More than 4,000 flavonoids (or bioflavonoids, as they are
sometimes called on supplement labels) have been identified,
and scientists suspect that there may be many more still to
be discovered in nature. Flavonoids give color to fruits,
vegetables, and herbs and are found in legumes, grains, and
nuts as well. They are also potent antioxidants; some are
even more powerful than vitamin C or vitamin E in preventing
cell damage caused by unstable oxygen molecules (free radicals).
So far only a few flavonoids have been investigated for their
healing potential.
One of these, quercetin (found in onions and apples), also
serves as a building block for other flavonoids. Rutin and
hesperidin are the most I active of the so-called citrus flavonoids,
which, as the name suggests, are present in oranges, grapefruits,
tangerines, and other citrus fruits.
Other flavonoids include PCOs (or procyanidolic oligomers;
also called proanthocyanidins), anthocyanosides, polyphenols,
and genistein. PCOs are plentiful in pine bark and grape seed
extracts and in red wine. Anthocyanosides are found in the
herb bilberry. Green tea is the primary source of polyphenols,
especially EGCG (epigallocatechrn-gallate), which experts
believe is possibly the most effective cancer-fighting compound
yet discovered. Genistein, found in soy products, has antioxidant properties and can also mimic the effects of estrogen.
What Does It Do
The disease-fighting potential of flavonoids stems from their
ability to reduce inflammation, prevent the release of histamine
(which causes allergy symptoms such as congestion), fight
free radicals, boost immunity, strengthen blood vessels, and
increase blood flow, among other actions.
Common Uses
• Reduce the risk of heart disease.
• May prevent breast, prostate, and other types of cancer.
• Lessen the chance of age-related vision problems,
such as cataracts or macular degeneration.
• Minimize the symptoms of hay fever and asthma.
• Fight viral infections.
Prevention
The flavonoids quercetin and PCOs may protect against heart
disease and other circulatory disorders because they inhibit
bodily changes that can lead to blocked arteries; they also
help strengthen blood vessels in a variety of ways. Studies
from Finland and the Netherlands found that people who get
plenty of flavonoids, particularly quercetin, have a reduced
risk of developing heart disease or having a stroke. In one
study, a diet high in flavonoids appeared to cut the chances
of dying from heart disease by 50% in women and 23% in men.
Another study reported a 75% drop in stroke risk for men who
had the highest intake of flavonoids, compared with those
who had the lowest.
Polyphenols and quercetin have shown promise as anticancer
compounds. Studies found lower rates of stomach, pancreatic,
lung, and possibly breast cancer in people with a high intake
of these flavonoids. In addition, soy-based genistein may
help fight breast cancer and minimize hot flashes by interacting
with estrogen receptors in the body. Quercetin also aids the
body in using blood sugar and so may be valuable in preventing
diabetes. Furthermore, it inhibits the buildup of sorbitol
(a type of sugar) in the lens of the eye, a cause of cataracts.
Additional Benefits
Quercetin may help relieve hay fever, sinusitis, and asthma
because it can block allergic reactions to pollen and reduce
inflammation in the airways and lungs. This anti-inflammatory
action also makes it useful for bug bites, eczema, and related
skin conditions, as well as for inflammatory disorders of
the joints and muscles, such as rheumatoid arthritis, gout,
and fibromyalgia. Because they strengthen blood vessels, PCOs
and citrus flavonoids are helpful in repairing varicose veins
and hemorrhoids. Rutin and hesperidin play a role in preventing
bruising.
How to take it
Dosage: For general health benefits: Buy a flavonoid
mixture that contains several types (such as quercetin, rutin,
and hesperidin) and follow the dosage instructions on the
label. For allergies, asthma, gout, and insect bites: Take
500 mg quercetin two or three times a day.
Guidelines For Use: Grape seed extract and
green tea are excellent sources of flavonoids and exert an
antioxidant effect as well. It’s usually best to combine
flavonoids with vitamin C to enhance their protective properties.
Quercetin should be taken 20 minutes before meals; other flavonoids
can be taken at any time of the day.
Possible Side Effects
There are no known toxicities, adverse reactions, or other
side effects from flavonoids.
Shopping Hints
• Mixed preparations of citrus flavonoids are the most
widely available and the least expensive supplements of this
type. But they are also the least active, often providing
a flavonoid content of only 50%. You’ll get more value
for your dollar by choosing preparations that contain pure
rutin, pure hesperidin, or possibly both.
• Flavonoids are sometimes mixed with vitamin C, and
the combination is labeled and sold as vitamin C complex.
It’s usually less expensive, however to buy vitamin
C and flavonoids separately, which also allows you to vary
your dose as needed.
Did You Know?
Eating an apple a day has always been associated with good
health, and a recent study suggests that quercetin may be
the magic ingredient. Lung cancer risk fell by 58% in people
who ate the most apples (a major source of quercetin) compared
with those who ate the fewest apples.
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