Green Tea
Polyphenols Inhibit Formation and Growth of Skin Cancer Tumors
Study description:
It seemed clear that green tea polyphenols
could protect against UVB-induced skin cancer. But scientists at the Department of Dermatology
at the University of Alabama wanted to find out how the polyphenols did this.
Type of study: Animal
What happened:
The researchers
divided hairless mice into three groups:
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One group was
given plain water to drink, and was exposed to UVB radiation 3 times a
week for 24 weeks.
-
The second
group was given water plus green tea polyphenols, and was also exposed
UVB radiation 3 times a week for 24 weeks.
-
The third
group, serving as the control group, was given plain drinking water
and was not exposed to radiation.
At the end of the
study period, the researchers compared the two groups that had been
exposed to radiation. The group that received the green tea polyphenols
had 35% fewer new tumors, 63% less tumor multiplicity, and 55% less
tumor growth. The tea polyphenols appeared to inhibit angiogenesis (the formation of a
blood supply for new tumors), and activate the immune system’s T cells,
which fight cancer in its earliest stages.
Researchers' conclusion:
Green tea polyphenols interfered with the
growth of tumors by slowing the growth of the new blood vessels that tumors need to
grow and survive, and by strengthening the immune system’s ability to fight
cancer.
Citation:
Mantena SK, Meeran SM, Elmets CA, Katiyar SK. Orally administered green tea
polyphenols prevent ultraviolet radiation-induced skin cancer in mice through
activation of cytotoxic T cells and inhibition of angiogenesis in tumors. Journal
of
Nutrition 2005; 135(12):2871-77. (Click here to read PubMed study
abstract.)
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Nadine Taylor, M.S., R.D. presents
GreenTeaLibrary.com,
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