Green Tea Blocks Activity of Cancer Drug

The dark side of green tea.

"Some cancer patients who take green tea to fight the disease may have it backward: the popular dietary supplement actually blocks the effect of bortezomib (Velcade) and similar anticancer drugs, a researcher said here.

Green tea supplements are being widely investigated for possible anticancer effects and many patients already self-medicate with them, according to Axel Schönthal, Ph.D., of the University of Southern California.

But if they're also taking bortezomib -- a proteasome inhibitor used in multiple myeloma -- green tea supplements can ensure that the drug is ineffective, Dr. Schönthal said at the annual meeting of the American Association for Cancer Research here.

'We expected the opposite -- that it would enhance the therapeutic effect of bortezomib,' Dr. Schönthal said.

The implication of the findings, he said, is that physicians should tell patients taking the drug that green tea supplements are completely contraindicated, although 'one cup probably would not be harmful.'"

Still think they know what a healthy supplement is?

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