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How Green Tea Fights Cancer
Green tea fights cancer at nearly every stage of the cancer process. Lab and
animals studies have found that some of
its most important anti-cancer properties include the following:
Antioxidant Action
The best way to fight cancer is to stop it from occurring in the
first place. And that's what antioxidants do. They help the body defend itself
against free radicals, the unstable molecules that damage cell membranes and
DNA, causing cancer, heart disease and other illnesses.
The catechins in green tea, particularly EGCg and EGC, have been
found to be the most powerful of all antioxidants. They show stronger anti-free
radical and anti-mutagenic abilities than such celebrated antioxidants as
vitamins C and E, resveratrol, selenium, glutathione, quercetin, curcumin and
even the food preservatives BHT and BHA.1
Protection Against Alterations to the DNA
A team of American and
Chinese researchers tested the effects of green tea catechins and a water
extract of green tea on known cancer-causing substances.2 They found that
green tea and green tea extract were both
capable of
protecting against the gene-altering damage that is an initial step in the cancer
process.
Among their findings were that both substances inhibited mutations induced by the
powerful carcinogens benzo(a)pyrene (found in charbroiled meat) and aflatoxin B1
(a toxin produced by a kind of mold that can grow on grains, nuts and animal
feed).
Inhibition of Tumor Activation
Many studies have shown that green tea catechins can inhibit
tumor activation. One study that was done by researchers at the Laboratory for Cancer Research
at Rutgers University found that giving green tea orally inhibited the formation
of tumors in the forestomach and lung in mice already initiated with
carcinogens.3 Any tumors that the mice did develop were markedly smaller.
Cell Cycle Arrest
The cell cycle is a series of stages that a cell goes through in
order to divide and reproduce itself. In cancer, the cell cycle can occur rapidly, with cancer
cells reproducing by leaps and bounds. But green tea catechins have been shown to
stop (arrest) this rapid division of cancer cells, thus slowing the growth of
cancerous tumors. And the catechins do this without damaging normal cells.4
Blocking the Blood Supply
A major way of fighting cancer is by blocking angiogenesis, or
the establishment of a blood supply to feed the tumor. If
the tumor can't establish a blood supply, it dies. Many studies have documented
green tea's ability to inhibit the process of angiogenesis, which slows or stops
the growth and spread of tumors.5
Promoting Self-Destruction of Cancer
Cells
Normal cells are programmed to self-destruct after a certain period (a process
called "apoptosis") in order to make way for new ones. But cancer cells don't
self-destruct -- that's part of the problem. They just keep growing and
multiplying.
One way to treat cancer is to induce apoptosis, often
through the use of powerful medications. However, in most cases these
medications also kill healthy cells. Yet green tea has been shown to induce
apoptosis in cancer cells without causing damage to healthy cells.6
Not a Cure, But It May Help...
While there is no cure for most kinds of cancer, scientifically sound studies
conducted by scientists at major universities and health institutes around the
world have shown that green tea and green tea extract pack a powerful punch
against this deadly affliction. This means that green tea may play an important
part in helping us to live longer, healthier lives.
Click on the following for a simplified look at the studies of green tea's
effects on:
Cancer in general
Breast
Cancer
Lung
Cancer
Prostate Cancer
Skin Cancer
Stomach Cancer
1 Pillai
SP, Mitscher LA, Menon SR, et al. Antimutagenic/ antioxidant activity of green
tea components and related compounds. J Environ Pathol Toxicol Oncol
1999;18(3):147-58.
2 Wang
ZY, Cheng SJ, Zhou ZC, et al. Antimutagenic activity of green tea polyphenols.
Mutation Research 1989;223:273-85.
3
Conney A, Wang Z, Huang M, Ho C, et al. Inhibitory effect of green tea on
tumorigenesis by chemicals and ultraviolet light. Prev Med 1992;21:361-69.
4
Chen D, Daniel KG, Kuhn DJ, et al. Green tea and tea polyphenols in cancer
prevention. Front Biosci 2004;9:2618-31.
5
Beltz
LA, Bayer DK, Moss AL, Simet IM. Mechanisms of cancer prevention by green and
black tea polyphenols. Anticancer Agents Med Chem 2006;6(5): 389-406.
6 Ahmad
N, Feyes DK, Nieminen AL, et al. Green tea constituent
epigallocatechin-3-gallate and induction of apoptosis and cell cycle arrest in
human carcinoma cells. J Natl Cancer Inst 1997;89:1881-86.
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Nadine Taylor, M.S., R.D. presents
GreenTeaLibrary.com,
the most comprehensive collection of scientific information
describing the health benefits of green tea.
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