Green tea blocks effect of cancer drug Velcade

Green tea has been has been hailed as the wonder drink with health benefits ranging from to cardiovascular protection to anti-cancer properties. Tea contains large amounts of antioxidants that protect the body from oxidative stress.

However, a recent study showed that some components of green tea can interact with certain chemotherapeutic drugs and interfere with these drugs’ functioning.

Researchers at the University of Southern Carolina found that green tea interferes with the therapeutic effect of the drug Velcade (generic name bortezomib) and renders the drug ineffective. Velcade is used in the treatment of multiple myeloma and mantle cell lymphoma

The culprit, the exact compound that counteracts the effect of Velcade has been identified as the green tea component EGCG. It seems that EGCG binds with the Velcade molecule so that the drug is no longer capable in binding with its targets in the tumor cells. The results of the study came as a surprise and a disappointment because the researchers actually hoped for the opposite effect.

According to lead author Axel H. Schönthal, associate professor in the Department of Microbiology and Immunology at the Keck School of Medicine of USC

“Our finding that GTE or EGCG blocked the therapeutic action of Velcade was completely unexpected. Our hypothesis was that GTE or EGCG would enhance the anti-tumor effects of Velcade and that a combination of GTE with Velcade (or EGCG with Velcade) would turn out to be a superior cancer treatment as compared to treatment with Velcade alone.”

The study was performed in lab mice with tumors and was part of a larger project called “Yin-Yang Properties of Green Tea Extract in Combination Cancer Chemotherapy: From Encouragingly Beneficial to Dangerously Detrimental.”

In recent years, herbal supplements such as green tea has become very popular in the easing the side effects of cancer treatments. In the case of Velcade, the drug is rendered inactive when the patient drinks green tea. Being inactive also results in lack of side effects. That is why patients tend to feel better after drinking the tea. The side effects are gone but so is the therapeutic effect of the drug.

However, this blocking effect of green may be only unique to Velcade and similar drugs. Other studies show that EGCG – drug interactions may have some positive, even synergistic effects.

In the meantime, it is highly recommended that patients on Velcade should stop drinking green tea. As for those who are not on Velcade, check with your oncologists how green tea can affect your therapy.

For more information about green tea check out:

• Film feature: The Meaning of Tea
• Can a cup of green tea a day keep the doctor away?
• Tea consumption and cognitive impairment and decline in older Chinese adults
• Black tea–helpful or harmful? A review of the evidence

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