
Vol. 3, # 29
August 5, 2006
Q: What are bioflavonoid? - Layperson
A: Researchers have reported over eight hundred different
bioflavonoids. Most of these are the yellow pigments found in citrus fruit as
well as other fruits and vegetables, these are referred to as flavonoids.
Four categories:
- most potent PCOs are those bound to other PCOs
- exist in many plants and red wine
- commercially available sources are from grape seeds and bark from the
maritime pine
- serves as backbone for other flavonoids such as citrus flavonoids:
rutin, quercitrin, hesperidin
- these derivatives have sugar molecules attached to the backbone
- most active of the flavonoids
- include rutin, quercitrin, hesperidin, naringin
- standardized mixture of rutinosides known as hydroxyethylrutosides (HER)
- clinical results have been obtained in treatment of capillary
permeability, easy bruising, hemorrhoids, and varicose
veins
- derived from tea plant camellia sinensis
- produced by steaming the fresh cut leaf
- polyphenol indicates presence of phenolic ring in the chemical structure
- polyphenols = flavonoids
- polyphenols in green tea: catechin, epicatechin, epicatechin gallate,
epigallocatechin gallate, and proanthocyanidins
- epigallocatechin gallate = most significant active compound
Bioflavonoids are also referred to as vitamin P, a name that nutrition
scientists object to because it has not been proved that they are essential to
human nutrition and health. Many researchers are studying bioflavonoids and many
reports have been given about their possible functions. Some researchers believe
that bioflavonoids help maintain capillaries. Capillaries are microscopic blood
vessels that allow the oxygen, hormones, nutrients, and antibodies to pass from
the body’s bloodstream to individual cells. If a capillary’s walls are too
fragile they will allow blood to drain out of the vessels and into the cells.
The result of this is easy bruising, brain and retinal hemorrhages, bleeding
gums and other abnormalities.
Bioflavonoids
also in recent studies have been shown to help the blood clot, this alone can be
helpful in treating phlebitis and other clotting disorders. Many bioflavonoids
prevent the cellular damage caused by free radicals; these are unstable
molecules that are formed when the body burns oxygen. Some bioflavonoids are
used as food preservatives to prevent fats from oxidation. Some reports show
bioflavonoids are useful in enhancing the antioxidant action of certain
nutrients.
Bioflavonoids and vitamin C are found in many of the same foods and the body
metabolizes both of these in the same manner. Researchers have discovered that
some of the functions that vitamin C is credited with is actually from the
bioflavonoids. Since they work so close together numerous reports have stated
that vitamin C and many bioflavonoids need each other to produce the effects
that they have on the immune system.
All these uses of bioflavonoids are the main reason that they are accredited
with the use they have at preventing many heart diseases. Many laboratory
studies show how bioflavonoids stop or slow the growth of malignant cells, they
also help protect against cancer-causing substances invading the heart and blood
cells. Bioflavonoids also act as natural antibiotics for the human body. Some
bioflavonoids destroy certain bacteria that are found in foods, this prevents
food spoilage and protects humans from food-borne infections.
Bioflavonoids are under study for many medical uses such as prevention of
easy bruising and many other bleeding abnormalities. Rutin, which is a
bioflavonoids that is found in wheat leaves and some other plants, are being
studied for reducing tissue damage. All these and many others bioflavonoids are
available as nutritional supplements
Are there any side effects or
interactions?
No consistent side effects have been linked to the flavonoids except for
catechin, which can occasionally cause fever, anemia from breakdown of red blood
cells, and hives. These side effects subsided when treatment was
discontinued.
Interactions
- Do not interact with any drugs
- citrus bioflavonoids containing naringin may interact with drugs
- naringin is found in grapefruit juice
- can increase oral bioavailability of drugs like nifedipine, felodipine,
verapamil, and terfenadine
- inhibits breakdown of various drugs including: caffeine, coumarins, and
estrogens
- Vitamin C-Bioflavonoids may enhance the effects of vitamin C
In 1980, quercetin was reported to induce cancer in animals. Most further
research did not find this to be true, however. While quercetin is mutagenic in
test tube studies, it does not appear to be mutagenic in animal studies. In
fact, quercetin has been found to inhibit both tumor promoters and human cancer
cells. People who eat high levels of flavonoids have been found to have an
overall lower risk of getting a wide variety of cancers, though
preliminary human research studying only foods high in quercetin has found no
relation to cancer risk one way or the other. Despite the confusion, in recent
years experts have shifted their view of quercetin from concerns that it might
cause cancer in test tube studies to guarded hope that quercetin has anticancer
effects in humans.
The flavonoids work in conjunction with vitamin C. Citrus flavonoids, in
particular, improve the absorption of vitamin C.
Bioflavonoids: Rutin and
Hesperidin share left / right-sided cell receptors and may be
considered
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essential to
human health. (Bio)flavonoids comprise the most abundant group
of plant Polyphenols,
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next to Phenolic
acids (found in a variety of foods),
Stilbenes (resveratrol, pinosylvin,
isorhapontin),
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and Lignans (nuts, seeds, whole grain cereals). Several thousand
flavonoids have been identified,
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which provide much of the flavor and color in fruits and
vegetables, and also berries and flowers.
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As a group with other polyphenols, flavonoids have been
linked to reduced cardiovascular disease,
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cancer and osteoporosis, and many other health benefits as a
result of their antioxidant, antibacterial,
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properties. |
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Following are some of about a dozen researched categories on
flavonoids or bioflavonoids:
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Flavonols Flavanones Flavones Flavanolols Flavanols
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vegetables, citrus fruit, celery, parsley, milk
thistle, tea,
cocoa,
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fruits, onions, licorice, red peppers, garcinia epuctata, chocolate,
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grape seed,    chamomile, mint, propolis, azaleas,
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pine bark,     ginkgo biloba,   grape
seed,
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Rutin  Hesperidin Flavone Silymarin Flavan
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Fisetin Hesperitin Apigenin Silibinin Catechin
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Morin  Naringin Apigetrin Taxifolin Epicatechin
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Myricetin Naringenin Luteolin Pinobanksin Gallocatechin
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Myricitrin Eriodictyol Baicalein
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Quercetin Pinocembrin Chrysin
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Quercetrin Likvirtin Techtochrysin
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Galangin Liquiritin Diosmin
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Spirenoside Liquiritigenin Diosmetin
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Robinin Eriocitrin Hispidulin
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Rhamnetin Neohesperidin Tangeretin
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Kaempferol Poncirin Eupafolin
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Kaempferide Isosakuranetin Eupatilin
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Flavonoids /
Bioflavonoids
(bioflavinoids) are accessory nutrients to form an ascorbic acid
or
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Vitamin C complex. Rutin and hesperidin are part of
this Vitamin P group and function synergistically
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with Vitamin C in regard to maintaining healthy capillaries,
to help form collagen in connective tissue,
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| to help heal wounds, and to support a healthy immune
system. |
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Rutin and/or hesperidin, when low, frequently result in predictable,
and even side-specific medical problems that include a greater
risk for vascular degeneration, bruising / capillary fragility, nose
bleeds,
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periodontal bleeding, varicose veins, hemorrhoids and
aneurysm, with few individuals exhibiting optimal
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levels, even after mega-supplementation. One reason is
the chemical interaction of bioflavonoids with
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other nutrients, which can have a synergistic or inhibiting
effect on them. Various drugs are also able
to
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interact with (bio)flavonoids and affect their
efficacy.
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Copper is the most common and potent
inhibitor of hesperidin and Vitamin C, being the reason why high
levels of copper create a greater risk for vascular degeneration,
which in turn requires greater
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intake of Vitamin C, sulfur,
chromium, or molybdenum to lower copper - to make it more
bioavailable, otherwise hesperidin levels will not go up, no matter how much is
supplemented.
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Abnormal liver functions, triggered by
drugs, hormones - particularly
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elevated estrogen - alcohol, etc., or the structural changes
experienced during pregnancy, as well as
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lack of exercise and excessive amounts of time spent in a
sitting position can be equally responsible
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to promote vascular degeneration.
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Hesperidin has a right-sided cell receptor (as
has copper), so medical problems associated with
its
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deficiency, and/or with copper excesses, are invariably
right-sided as well. It is not unusual to see hemorrhoids
or varicose veins being noticeably worse on one side only.
Rutin is inhibited mostly
by
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chromium, and since chromium levels
are on average not as high as copper levels, rutin levels
are invariably higher than hesperidin levels as long as dietary
intake of rutin and hesperidin are similar.
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Vanadium and
selenium support rutin uptake, and molybdenum and sulfur support
hesperidin uptake.
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Rutin + hesperidin
are associated the same way as calcium + magnesium, in that taking
only the one
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can over time
deplete the other. For instance, the need to supplement rutin
alone (without hesperidin) can only be justified when there is
either a notable deficiency ratio-wise to hesperidin, or when
there
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is a significant
vascular problem, which is confined to the left side
only.
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Measuring the
actual levels of bioflavonoids will help establish whether they, or
other aspects such as impaired liver functions or drugs are
causative factors with vascular degeneration. Low to
moderate intake of alcohol or blood thinning medications
favorably enhance the activity of flavonoids, however excessive
intake compromises not only Vitamin K, but causes a sharp drop with
rutin and hesperidin levels. (see also Acu-Cell "Osteoporosis" on
details on Vitamin K and its DRI / RDA).
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Citrus
Bioflavonoids are the most commonly supplemented forms of
flavonoids. Unless there is an
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allergy or
intolerance to citrus (some individuals find that flavonoids,
particularly from citrus worsen their
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eczema), there are
no other adverse or overdose reactions known, even when very high
amounts are
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supplemented every
day. Since citrus bioflavonoid tablets are usually quite
large, brands should be
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chosen that either
supply oval-shaped tablets, caplets, or capsules for easier
swallowing.
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Anthocyanins and
their precursors Proanthocyanins (also called condensed tannins) are
chemically related to quercetin, and they are another class of
flavonoids that are excellent antioxidants with similar benefits
to other bioflavonoids. Pycnogenol, which comes from the bark
of the French Maritime Pine
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(pinus maritima),
is a particularly promoted and well-known source of
proanthocyanidins. While their
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cost is several
times that of citrus bioflavonoids, tablet sizes are only a fraction
of those containing other
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types of
flavonoids, so they are easier to take for individuals with
swallowing difficulties, or children.
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•
Anthocyanidins are found in tea, beets, cherries, plums, red grapes,
hawthorn, and some berries,
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(cyanidin, delphinidin, pelargonidin,
peonidin, petunidin, malvidin).
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•
Proanthocyanidins are found in tea, bilberry, apple, pear, grape
seed, pine bark, beer, red wine,
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 cranberry, red beans, (procyanidin,
prodelphinidin, propelargonidin). |
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Isoflavones from
soy products (genistein, daidzein, glycitein), are another class of
flavonoids that
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function as
antioxidants and in addition possess phytoestrogenic properties that
can be effective for
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menopausal
symptoms and to promote bone density in post-menopausal women.
They may also be
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beneficial in the
treatment and prevention of cardiovascular disease (inhibition of
lipoprotein oxidation,
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thrombin formation
and platelet activation), and cancer (inhibition of angiogenesis,
and tyrosine kinase
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activity - an
enzyme that promotes cancer growth), although there are conflicting
opinions on the tumor-
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protective
benefits in light of new evidence of also a possible pro-tumor
effect following high soy intake.
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Isoflavones are
mostly found in soybeans, garbanzo beans, chick peas, red clover and
legumes.
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Cocoa is an
excellent source of catechins, which are polyphenols of the flavanol
group, and which are
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believed to
protect against heart disease, cancer, and various other medical
conditions. While health
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benefits apply to
some isolated compounds in cocoa - as a whole - they do not apply to
processed cocoa products such as Chocolate any longer because of
other less desirable ingredients offsetting
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these health
benefits (i.e. added sugar, corn syrup, milk fats / dairy cream,
hydrogenated oils, etc...),
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and also since the
actual cocoa content may be less than 20% in most chocolate bars
sold. (see also
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Acu-Cell
"Chocolate" for more details on some of the positive / negative
health effects of chocolate).
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Theobromine, found
in chocolate, can be toxic or even lethal to domestic animals such
as dogs, cats,
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horses and many
other animals as a result of affecting their kidneys, heart, and
central nervous system.
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In addition, cocoa
products contain a high level of copper, which - with few exceptions
- is already too
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high in many
individuals, and so consuming a lot of chocolate aggravates many
high copper-related
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medical
conditions, or creates additional ones (see also Acu-Cell Nutrition
"Chromium & Copper").
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Horse Chestnuts
contain flavonoids, sterols, and tannins. Studies have
identified a saponin known
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as Aescin as the
active constituent in horse chestnut extracts, which has been found
effective in the
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treatment of
chronic venous insufficiency, varicose veins and edema, and can be
taken topically or
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internally.
Extracts of the seeds, leaves and bark of the horse chestnut
tree (aesculus hippocastanum)
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have been
traditionally used in Europe for vascular degeneration, hemorrhoids,
water retention, cough,
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rheumatism,
phlebitis, skin problems and other ailments.
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People with kidney
or liver conditions should avoid horse chestnuts or any horse
chestnut extracts, as the aescin may worsen their functions.
Reactions such as nausea, stomach upsets, and itching are another
possibility in people sensitive to horse chestnuts.
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Quercetin
(quercitin, quercetrin) is chemically related to a class of
flavonoids called (pro)anthocyanins.
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Early research on
quercetin suggested that ingesting higher amounts may induce cancer,
after it failed
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a standard - but
somewhat controversial laboratory test called the Ames Test.
This test supposedly
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identifies
chemicals that might be carcinogenic. Subsequent studies
however disputed those earlier
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findings and
attributed cancer-protective or cancer-fighting properties to
quercetin instead.
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In addition,
quercetin has been found to be an effective hyperthermia sensitizer,
making it a potential
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adjunct
therapeutic agent in the treatment of various cancers that are
sensitive to heat stress (prostate,
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ovarian, uterine,
or cervical cancer, leukemia, melanoma, colon adenocarcinoma, and
others).
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However, I have
seen a few patients who developed cancerous tumors after
supplementing quercetin -
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which proves that
positive outcomes in experimental studies are not necessarily
reflected in positive
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outcomes when
applied in a "real world" environment. At the same time,
patient feedback on the touted
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anti-allergenic
and anti-inflammatory aspects of quercetin has not been all that
favorable either, so while
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this is not
intended to discourage anyone from using it for a specific condition
(particularly when found
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beneficial),
quercetin nevertheless fits the "Caveat Emptor"
category.
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Quercetin isn't
the first to be listed among naturally occurring carcinogens and
mutagens found in foods
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and beverages.
Many phytochemicals contained in common fruits, vegetables,
spices, grains, seeds,
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nuts, mushrooms,
coffee, tea, and herbs are rodent carcinogens, while for instance
Psoralens (found
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in parsnips,
parsley and celery), are considered to be human carcinogens, as is
acrylamide, contained
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in crisp breads
and rolls, which is also a neurotoxin. Ingesting large amounts
of Grape Seed Extract has shown liver toxicity in some animal
studies as well.
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Nevertheless, test
tube and animal studies - where many times astronomical amounts of
food fractions
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are used - have
generally little relevance to normal human consumption of these same
types of foods, but they make great headlines, or they may assure
next year's research grant for an otherwise starving research
team. |
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Dietary Reference
Intake (DRI) is the latest term replacing daily dietary reference
values such as
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Adequate Intake
(AI), Tolerable Upper Intake Level (UL), Estimated Average
Requirements (EAR),
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Nutrient Reference
Value (NRV), and Recommended Dietary Allowance / Intake
(RDA / RDI).
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Therapeutic
Range:  50mg - 500mg+   Therapeutic Range:  50mg -
500mg+ |
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Usually taken in
the form of Citrus Bioflavonoids:  Therapeutic Range:  500mg -
5,000mg+ |
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Rutin and
Hesperidin (and related flavonoid compounds):
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Low Levels /
Deficiency - Symptoms and/or Risk Factors:
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Vascular
degeneration, vascular bleeding (bruising / capillary fragility,
nose bleeds, periodontal bleeding, varicose veins, hemorrhoids
and aneurism),
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High levels /
Overdose / Toxicity / Negative Side Effects - Symptoms and/or Risk
Factors:
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Allergic
reactions, skin rash, stomach ache,
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Sources of Rutin
and Hesperidin:
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Mainly found in
the rind, pulp, skin of fruits such as lemons, grapefruits, oranges,
lime, grapes, cherries,
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plums, peaches,
apricots, apples, berries..., vegetables such as green and yellow
peppers, tomatoes,
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onions, broccoli,
parsley..., also bee propolis, green tea, black tea, whole grains
such as
buckwheat | |
The bioflavonoids are relatively safe to use, but, as usual, consult the
appropriate healthcare professional familiar with the use of
bioflavonoids.
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DISCLAIMER: The information in this column, is NOT intended to diagnose and/or treat any health related issues and is provided solely for informational purposes only. Consult the appropriate healthcare professional before making any changes to your healthcare regime. Even what may seem like simple changes in the diet for example, can interact with, and alter, the efficiency of medications and/or the body's response to the medications. Many herbs and supplements exert powerful medicinal effects. Neither the author, nor the website designers, assume any responsibility for the reader's use or misuse of this information.
© 2002 Nature's Corner
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