Protect you heart and brain while
preventing cancer
Edited by Russell L. Blaylock,
MD, and lightly abridged by Roger French
Tea isn’t just a refreshing drink
anymore. Numerous stories have appeared in the popular press touting the health
benefits of green tea, including anti-cancer effects, weight loss and
antioxidant properties.
In fact, over 1,400 medical
articles have been written on the medical benefits of green tea in the last 10
years.
There is a lot of confusion about
the differences between white tea, green tea, oolong tea, and black tea. They
are all derived from the same tea plant, Camellia sinesis, and for all of them,
only the tip of the plant is picked. The differences among these teas lie in
the processing, mainly in relation to the degree of oxidation. In most teas,
enzymes in the more mature leaves trigger oxidation after picking, and to
arrest this, the leaves are heated.
White Tea is composed of new
growth buds from the tips of the tea plants. This tea undergoes the least
amount of processing. Since it doesn’t undergo oxidation, it is never heated or
fermented.
Green Tea, a favourite drink
among millions of people, makes up 20 percent of the world’s production,
undergoes minimal oxidation (fermentation) by applying heat early in the
processing. This inactivates the fermentation enzyme, phenolase. Its health
benefits are numerous and have more scientific documentation
Oolong Tea is oxidized to a
degree somewhere between green and black tea, usually within two to three days
of picking. The Chinese call this ‘blue tea’.
Black Tea is what most people
consider ‘tea’. The leaves are black because they are fully oxidized, usually
for two weeks to a month. This process releases a group of compounds called
tannins, which have anti-cancer effects, especially for colon cancer. The
levels of catechins, which are responsible for most of the medicinal benefits,
are substantially lower in black tea.
WHAT MAKES TEA GOOD FOR YOU?
Teas contain a number of active
compounds, including catechins, quercetin, kaempferol, chlorogenic acid,
theanine, theobromine and theophylline.
Of greatest interest to
scientists are the catechins, which may reduce stroke, heart failure, cancer,
and diabetes. Green tea contains approximately 30 percent catechins, and white
tea contains even greater amounts. The lowest levels are in black tea.
Tea is a major source of
quercetin in the diet. Quercetin is a potent flavonoid that is
anti-inflammatory. It also protects against cancer and protects the brain.
Unfortunately, tea also contains
high levels of two toxic substances, fluoride and aluminium. Studies have shown
that little of the aluminium in tea is absorbed by the body because it is bound
by catechins (flavonoids) in the tea. Yet, squeezing lemon in teadramatically
increases aluminium absorption, somewhere close to 700 percent, so tea would be
better flavoured with mint for example.
The lowest levels of both of
these toxins are found in white tea, and the highest levels are in black tea.
Brick tea, which is made from black tea leaves and stems, has tremendously high
levels of fluoride, so high that it regularly causes fluorosis, which can
damage the skeleton, teeth and organs, including the brain.
Both toxins are absorbed from the
soil, and the tea plant has a unique ability to concentrate them in its leaves.
High levels of these two toxins in the soil are a particular problem with tea
grown in India and China.
White tea, because it is
harvested earlier than other forms of tea and is minimally processed, has a
higher concentration of catechins, quercetin and other nutrients. It also
contains far less fluoride and aluminium. Therefore, when I refer to a study
using green tea, you can substitute white tea in its place.
The two most powerful anti-cancer
components of teas are the catechin, epigallocatechin gallate (EGCG), and
quercetin. Both have been studied extensively. EGCG is a powerful antioxidant.
TEA CAN HELP WARD OFF CANCER
Abundant scientific research has
shown that drinking tea regularly, especially green or white tea, helps prevent
the development of cancer and even kills a number of types of cancer cells.
This applies to cancers of the colon, breast, prostate, lung, ovaries,liver
andbladder and leukaemia, myeloma (bone marrow cancer) andmelanoma.
Vegetable oils (omega-6 oils),
carrageenan, high-meat diets (especially seared meats) and MSG and other food
additive excitotoxins produce colon irritation and inflammation. Studies have
shown that EGCG, from green tea and white tea, prevented colon cancer in
experimental animals exposed to powerful cancer causing chemicals.(1) Studies
in both humans and animals implanted with human colon cancers have shown that
EGCG is a very powerful inhibitor.
A recent Japanese study found
that EGCG suppresses the metastasis (spreading to other parts of the body) of
colon cancer. Other catechins from green and white tea also inhibited tumour
invasion, which would significantly improve survival rates in cases of colon
cancer.(2)
Another study found that EGCG
inhibited COX-2 and NFkappaB, both of which are necessary for inflammation to
develop. In fact, NFkappaB is essential for cancer growth. Pharmaceutical
companies are working at a breakneck speed to develop a drug that will
specifically target these cancer-promoting enzymes – but they already occur in
a number of vegetables, fruits and teas. The amount required to prevent colon
cancer is equal to drinking two to three cups of strong white tea a day.
Studies have shown that women who
drink green tea regularly, such as Asian-Americans, have a lower incidence of
breast cancer. One study found that EGCG and green tea itself inhibited the
growth and invasion of breast cancer.(3)
Tea and its components slow the
development of cancer by suppressing signalling molecules needed for cancer
cell reproduction and by blocking enzymes needed for tumour invasion. This not
only helps prevent breast cancer, but should it develop, it would be likely to
be more curable.
In addition, studies have shown
tea has some benefit in preventing prostate cancers in humans and animals.(4)
Studies using a combination of
the amino acids, lysine, proline, arginine, as well as vitamin C and EGCG,
found that they inhibited the invasion and growth of prostate cancer and, at
high doses, increased the killing of cancer cells (apoptosis).(5) Of particular
interest is the discovery that green tea extract inhibits hormone-sensitive
cancers, including breast and prostate cancers.
A number of studies have shown
that green tea extract, and especially EGCG, inhibits haematological cancers
like leukaemia and multiple myeloma, a particularly nasty malignancy.
These studies show that EGCG
inhibits the growth of leukaemia cells and triggers their death.(6) Another
study found that EGCG stimulates the killing of multiple myeloma cells.(7)
Likewise, a number of studies
have shown EGCG curbs the invasion of bladder cancer and also reduces the
cancer growth.(8)
Studies have also found that EGCG
inhibits the development of lung cancer and reduces the growth of existing lung
cancers.(9)
Ovarian cancers are also
sensitive to the suppressive effects of EGCG. It has been found to inhibit
ovarian cancer in numerous ways, making it superior to chemotherapy.(10)
In relation to melanomas, recent
studies have shown that green tea may inhibit their formation. When the skin is
sunburned, it releases a large amount of nitric oxide which forms nasty
free-radicals that trigger the development of melanomas. Green tea extract,
taken orally and applied topically, can interfere with the production of nitric
oxide. The potent antioxidants in green tea, including high levels of
quercetin, are a powerful weapon against the growth and spread of melanomas.
POWERFUL LIVER PROTECTION
A concern with any flavonoid is
its ability to alter detoxification, which is a key function of the liver. Some
flavonoids, such as those in grapefruit, can inhibit detoxification of certain
prescription drugs and caffeine. This can increase the toxicity of the drug and
prolong the effects of caffeine. Studies of green tea extract have shown no
evidence that it changes the liver’s ability to detoxify chemicals.(11)
EGCG can protect liver cells from
the toxic effects of alcohol, mainly by its antioxidant and anti-inflammatory
activity.
In addition, EGCG has been shown
to protect the liver from autoimmune hepatitis by lowering the level of a
critical chemical and suppressing the overactive immune system. It has also
been shown to lower blood cholesterol levels, primarily by inhibiting the
absorption of cholesterol from the gut and by reducing the synthesis of
cholesterol by the liver.(12)
Not all reports endorse the use
of green tea extract, especially its concentrations of EGCG. One study found
that high doses of extract (much higher than can be obtained by drinking tea)
interfered with the mitochondrial (energy producing) function in liver cells,
which could have the effect of toxicity.(13)
Even though they admit that connections
to EGCG are not very strong, the United States Pharmacopeia has asked that
supplements containing concentrated EGCG be labelled with a warning that the
product should be stopped if abdominal pain, dark coloured urine or jaundice
occurs. People with a history of liver disease or damage should use the product
with caution.
To put benefits versus harm into
perspective, it has been shown that, at low to moderate doses, white and green
tea extracts (as with tea drinking) act as powerful antioxidants, but at very
high concentrations they can actually promote dangerous oxidation. Combining
the tea extracts with other antioxidants, such as vitamins E, C, K and D3,
helps prevent this toxic effect.
DRINK TEA — REDUCE FAT
When it was reported that green
tea caused a reduction in fat, commercial products began to appear on shop
shelves extolling the virtues of green tea extract as an aid for weight loss.
The studies show a reduction in
fat due to inhibiting the growth of fat cells(14) and to inhibiting fat
absorption from the gut.(15) However, the doses required to get this effect are
generally higher than those contained in the weight-loss products or by
drinking green or white tea.
Green tea also dramatically
reverses insulin resistance, the cause of type-2 diabetes.(16) It has been
found that EGCG acts like insulin(17) and that green tea extracts have a strong
protective effective in diabetic animals from diabetic nephropathy.(18)
HEART PROTECTION
EGCG has been shown to protect
the heart in many ways:
In cases of hypertension, from
enlarging;
From free-radical damage;
It reduces heart inflammation;
Green tea extract reduces high
levels of free-iron in the heart, free iron being associated with heart
failure.
EGCG has been shown to relax
arteries, thereby improving blood flow and lowering blood pressure. It has also
been shown to reduce atherosclerosis that is strongly associated with oxidized
LDL-cholesterol.
Green tea extract improves the
health of red blood cells without the side effects of medications.(19) This
allows blood to flow through arteries more easily.
Several studies have shown that
EGCG helps prevent strokes, and when strokes do occur, they are much less
severe when green tea extract is given.(20)
Finally, EGCG from green tea has
been shown to inhibit an enzyme called collagenase.(21) In excess, this enzyme
weakens the collagen that gives strength to blood vessels and other tissues.
Inhibiting it reduces the risk of varicose veins, haemorrhoids and leg oedema.
OTHER PROTECTION
A recent study using cells from
people with rheumatoid arthritis found that EGCG inhibited the inflammatory
cytokines associated with the disease.(22) The researchers concluded that green
tea extract holds promise in reducing the joint and tissue destruction
associated with rheumatoid arthritis.
Other studies have shown that
green tea extract represses the chemical that triggers the inflammation
associated with rheumatoid arthritis.(23) Green tea can reduce the pain,
swelling and disability associated with inflammation.
EGCG has been shown to reduce
inflammation in the intestines, which would be helpful with inflammatory bowel
diseases, such as ulcerative colitis.(24)
Other studies have shown that
EGCG significantly reduces the inflammation in the lungs associated with
smoking.
One would expect white and green
tea to reduce the incidence of autoimmune diseases as well. Two recent studies
have shown that green tea extract can significantly reduce the severity and
damage associated with two autoimmune diseases, Sjogren’s syndrome and
Lupus.(25)
A growing number of studies show
that green tea and white tea have powerful antibacterial, antiviral, and
antifungal activity. Tea has been shown to inhibit growth of the malaria organism,
a leading cause of death in the Third World.(26)
Another study looked at the
ability of EGCG to inhibit the growth of several organisms associated with
food-borne infections, such as E. coli, Staphylococcus aureus, Listeria
monocytogenes and Bacillus cereus.(27) While being active against all bacteria,
EGCG showed the greatest ability in fighting antibiotic-resistant
Staphylococcus aureus. Thus flavonoids may have the potential to treat
antibiotic-resistant organisms.
Newer studies confirm that green tea
extract and EGCG enhance the effectiveness of antibiotics against a number of
disease-causing organisms.(28) Drinking several cups of strong white tea daily
while taking antibiotics can make the drugs more effective.
Green tea extract has even been
found to inhibit HIV infections,(29) and EGCG has been shown to reduce the risk
of HIV-induced dementia.(30)
Flu in the elderly is
significantly reduced by gargling with concentrated green tea extract.(31)
If all this isn’t impressive
enough, recent studies have shown that the catechins from white and green teas
can suppress the growth of Candida organisms. In some cases, tea worked even
better than prescription antifungal medications.32)
BRAIN PROTECTION
As a neurosurgeon who works in
the field of neurodegenerative brain disorders, such as Alzheimer’s dementia,
Parkinson’s disease and ALS, I find the powerful protective effects of tea
compounds very interesting.
A considerable amount of research
has shown that green tea extract is highly protective of the brain. It has been
proven that EGCG reduces the brain’s generation of toxic beta amyloid, the main
feature in the Alzheimer’s brain.(33)
Alzheimer’s brains accumulate
considerable amounts of free iron. This iron tends to cause the beta amyloid to
mass together and form highly toxic microscopic crud in the brain as well as
accumulate tremendous amounts of free radicals. EGCG not only reduces the toxic
crud, it also binds the iron (a process called ‘chelation’), rendering it
non-toxic.
Free iron also plays a major role
in Parkinson’s disease and tends to accumulate in the brain long before
clinical signs develop. EGCG has been shown to reduce the incidence of Parkinson’s
disease in experimental models of the disease.(34) The antioxidant effect of
green tea extract is 10 times more potent than that of vitamin E.
One of the most destructive free
radicals found in all neurodegenerative disease, especially in Alzheimer’s, is
peroxynitrite. EGCG has been shown to be a strong suppressor of
peroxynitrite.(35)
EGCG has also been shown to
stimulate DNA repair, which is essential in protecting brain cells.
Excitotoxicity, the process by which nerve cells are damaged or killed, plays a
central role in virtually all neurodegenerative diseases, including multiple
sclerosis, Alzheimer’s, Parkinson’s and ALS. EGCG has been shown to
significantly impede excitotoxicity.
EGCG is also useful in protecting
the brain in cases of stroke, brain trauma and infections. Closely linked to
excitotoxicity is chronic activation of the brain’s immune system, which, when
occurring for prolonged periods, slowly destroys brain cells. This appears in
Alzheimer’s disease, autism, Parkinson’s disease, strokes, brain trauma,
encephalitis and ALS. Green tea represses the activation of the brain’s immune
cells.
EGCG and the other catechins
easily enter the brain, but only in low concentrations. Fortunately, large
amounts are not needed for the benefits.
Regularly consuming green tea
extract may significantly enhance memory and ability to learn.(36) It has also
been shown to have a sedative effect.
Both white and green teas contain
theanine which reduces stress, induces sleep and protects the brain from excitotoxicity.
A supplement containing pure theanine is available for treating sleep problems.
I have found that it induces deep sleep, but because you feel very tired the
next day, I would not recommend the supplement as a sleep aid. The levels of
theanine found in white and green tea are optimal for relieving stress and
relaxation, without the excessive tiredness.
KIDNEY STONES, SKIN AGEING
A recent study found that EGCG
significantly reduces the formation of calcium oxalate kidney stones by
lowering oxalate crystals in the urine.(37) These stones are common. If you
have a problem with kidney stones you may want to drink several cups of strong
white tea a day.
Not only can green tea protect
against UVB-triggered skin cancers, it also significantly protects against skin
ageing by protecting the DNA and promoting DNA repair in skin cells. The UVB
rays from the sun suppress immunity within the skin, a major process in skin
ageing. It has been shown that EGCG restores this lost immunity when applied
topically or taken orally. It has also been shown that EGCG can protect the
lens of the eye against UVB damage.
PROTECTECTION FOR THE EYES
A number of eye diseases,
including macular degeneration and glaucoma, are associated with oxidative
stress (caused by free-radicals and lipid peroxidation) within the retina at
the back of the eye where light falls. EGCG protects these nerve cells against
free-radical damage.
It has been shown that EGCG is 10
times more potent as an antioxidant than either vitamin E or vitamin C. The
best results are obtained by drinking white tea several times a day – as the
Chinese and Japanese do.
WHY DRINK WHITE TEA?
White tea stands out among the
different teas because it contains more catechins than the other teas,
including green tea, and also contains far less fluoride and aluminium.
I would recommend using two to
three bags of white tea per cup, and let simmer for at least 10 minutes.
Squeeze the bags repeatedly during simmering. Then remove the bags and squeeze
all the tea from the bags.
Long-simmered tea may be bitter,
but the more bitter, the better, because the bitterness is caused by the
beneficial catechins. Add some natural sweetener if you wish and maybe a few
leaves of mint.
Drink two to three cups a day.
Because the catechins stay in the blood for about five hours, three cups will
cover most of one day. You would want to drink more if you are treating a
disease, such as Parkinson’s or an infection.
Several companies make a
concentrated green tea extract. In some supplements, this is equivalent to 20
cups of tea. As stated, recent warnings of the risk of liver damage suggest
taking the supplement with a meal and watching for signs of liver damage, such
as abdominal pain, dark urine and jaundice (yellow skin). Taking other
antioxidants with the extract may help protect against liver injury.
A SUMMARY OF THE BENEFITS OF
TEAS
Tea has been tapped for its
medicinal properties for ages
Tea has proven strong in combating stroke,
heart failure, cancer, and diabetes
Among the different teas, white tea offers the
greatest benefits, as it undergoes the least amount of processing,
which is what distinguishes teas
Do not use lemon in tea – lemon increases absorption of the naturally
occurring aluminium in tea
Tea can help with losing weight
Tea is a great digestive aid
Tea can help protect the retina
from free radical damage that causes macular degeneration and glaucoma
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