Green tea may protect against colon cancer

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Green tea may protect against colon cancer

By Megan Rauscher Fri Dec 7, 1:27 PM ET

 

NEW YORK (Reuters Health) - An extract of green tea wards off colorectal cancer,

animal experiments show.

 

According to research reported at the Sixth International Conference on

Frontiers in Cancer Prevention, sponsored by the American Association for Cancer

Research, a standardized green tea polyphenol preparation (Polyphenon E) limits

the growth of colorectal tumors in rats treated with a substance that causes the

cancer.

" Our findings show that rats fed a diet containing Polyphenon E are less than

half as likely to develop colon cancer, " Dr. Hang Xiao, from the Ernest Mario

School of Pharmacy at Rutgers University, Piscataway, New Jersey, noted in a

statement.

 

These results are consistent with previously published results, which showed

that green tea consumption was associated with lower colon cancer rates in

Shanghai, China, he also noted.

 

In the study, Xiao and colleagues injected rats with azoxymethane, a chemical

known to produce colorectal tumors that share many characteristics with

colorectal cancer in humans. Then they fed the animals a high-fat Western-style

diet with or without Polyphenon E for 34 weeks. The amount of Polyphenon the

animals took in was roughly equal to about four to six cups of green tea per

day.

 

Polyphenon E decreased the total number of tumors per rat and decreased tumor

size, compared with control rats that were not given Polyphenon E, Xiao told the

conference.

 

" In the control group, " he said, " 67 percent of rats developed malignant tumors

while in the treated group only 27 percent of rats had malignant tumors. Most

important, tea polyphenols decreased the number of malignant tumors per rat by

80 percent compared to the control group. "

 

When the researchers analyzed blood and colon tissue samples, they found a

" considerable amount of tea polyphenols in those samples in treated animals, and

those levels of tea polyphenols were comparable to the human situation after

ingestion of tea leaves or tea beverage, " Xiao noted.

 

The researchers believe these findings will pave the way for clinical trials

with green tea polyphenols in humans.