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Green Tea Setback?

Green tea has a growing reputation as a health-promoting dietary supplement. Research in recent years has shown that it may reduce risk of cardiovascular disease and several kinds of cancer, for instance. Many people use green tea to help cope with chemotherapy's side effects.

But a new study casts a bit of a pall over that reputation. Researchers writing in the journal Blood found that the key component thought to give green tea its antioxidant power in fact hindered a cancer treatment. The catechin EGCG was found to actually block a drug used to treat multiple myeloma and mantle cell lymphoma from doing its job.

The finding caught researchers at the University of Southern California off guard: When they set out to test the drug Velcade plus EGCG on mice, they anticipated that adding the green tea component would boost the drug's tumor-busting effect.

Instead, they found that Velcade bonded to the EGCG instead of to the parts of the tumor cells it has to bond to in order to be effective. EGCG rendered Velcade completely impotent against cancer.

Though ethical concerns preclude the researchers' testing to see whether the same thing would occur in humans, the team believes the mouse-study findings likely would apply to people as well.

But they haven't given up on green tea or EGCG altogether. This study was part of a larger effort called "Yin-Yang Properties of Green Tea Extract in Combination Cancer Chemotherapy: From Encouragingly Beneficial to Dangerously Detrimental." (Whew!) The team expects that EGCG combined with other drug treatments may still be useful.

The researchers' work serves as a reminder that even seemingly benign dietary supplements such as green tea can interfere with the workings of conventional medicine. Until supplements are better understood by Western science, prudence dictates that we approach them with caution -- and that we be vigilant in reporting our use of them to our physicians and pharmacists, who can be on the lookout for potentially harmful interactions.

By Jennifer LaRue Huget  |  February 9, 2009; 7:30 AM ET
Categories:  Alternative and Complementary Medicine , Cancer  
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I'm a bit surprised to hear that green tea, or ANYTHING with caffeine, would be taken during chemotherapy. In my experience, anything containing caffeine is strictly off-limits during the course of chemotherapy. When you're undergoing chemo, it's a bit late for EGCG to do it's work... The time to load up on antioxidants is when you're healthy, or AFTER you are safely in remission - to help deter the onset or recurrance of the disease.

Posted by: theteaspot | February 9, 2009 2:10 PM | Report abuse

I agree.

My spouse recently completed a major treatment for cancer and the doctors have said - no vitamins or supplements, eat a balanced diet.

Who knows what these things actually do? Why take a risk?

Posted by: RedBird27 | February 9, 2009 3:25 PM | Report abuse


You bring up a good point about the supplements industry. It is easy to forget that it is not regulated. It's not like the FDA even has the ability to take it on since they have their hands full with melamine and salmonella. They have issued "warnings" on diet and weight loss supplements in the past, but it pretty much stops there.

I can say from my experience working as a hospital dietitian, we had to be concerned with drug / nutrient and supplement / nutrient interactions.

In my practice now, it is not uncommon to find clients with health issues on multiple supplements and they have little idea why they are taking the supplement or if they really need it. I've seen adverse health issues with over-supplementation.

So, to your point... yes, we need to know more about how supplements work in the body. More research, which costs money. But people need to also remove the "health halo" from supplements and turn the focus back to food.

In health,

Posted by: DCnutritionXprt | February 9, 2009 3:41 PM | Report abuse

I don't understand why caffeine would be detrimental. I am receiving chemo for breast cancer now and regularly drink green tea. My oncologist didn't recommend supplements, but said that a multi-vitamin plus calcium/vitamin D supplement would be fine.

Posted by: zsayman | February 9, 2009 5:49 PM | Report abuse

Yes, I can imagine that by the time you're in chemo or other extreme treatments, the green tea may be moot. But it seems so crazy to me to talk about green tea, a natural plant nutrient, as if it is the potentially harmful, toxic substance, when really it's these pharmaceuticals that cause as much harm as good. We are so indoctrinated that we can say crazy stuff like "watch out for the antioxidants in plants, they may harm you," while not questioning these toxic pharms that will literally kill you. Stunning. I agree with another poster that we really need to focus back on clean, unadulterated nutritious food. Green tea, in my mind, is just like the basil and parsley in my garden - not like a synthetic supplement produced in a lab.

Posted by: DCcomm | February 10, 2009 9:17 AM | Report abuse

To the people who think "natural" always means "beneficial" or at least harmless, think again. Eating tomatoes or potatoes is great for you. However, you can NOT eat the green leaves from a tomato or potato plant, because they will kill you. They have chemicals in them that are toxic. (You would not eat belladonna, right? Belladonna, a natural plant, makes atropine, which would kill you as a pill or as a single leaf from that plant.) You may drink green tea because it has antioxidants, which are natural chemicals that help your body. Even water is a chemical. Making a distinction between a natural chemical and a lab created chemical, both of which you take into your body, is an arbitrary and artificial concept.
I would not put green tea in my spaghetti sauce instead of basil or oregano. Why? Because the natural chemicals in green tea are different (not just taste different) from those in oregano and basil. Plants evolved those different chemicals as insecticides and protective agents. Their good taste to humans as spices and teas is a happy accident.
This article is saying that a natural chemical interferes with chemotherapy. It would not matter if you got that natural chemical from a pill or from a plant- it would still have the same bad effect on your body if you were on that particular chemotherapy. Assuming that any one plant (green tea leaves) from a garden is the same as another plant (basil, parsley, oregano, potato, tomato, or belladonna) is simply naive and uninformed.

Posted by: jerry_a | February 10, 2009 11:40 AM | Report abuse

I am undergoing treatment for ovarian cancer. I have a great oncologist who reviewed supplements several of other cancer friends have taken. Of course I had a consult with their M.D. with regards to my particular situation. My oncologist found nothing You can always fi wrong with his suggestions-including the green tea. I think she is impressed that I am pro-active-bringing in other voices as I go on this journey.There is always someone to tell you what you are doing is wrong. Next we will learn that meditation,yoga,guided imagery,and relaxation exercises do not help.

Posted by: lynneann222 | February 10, 2009 1:47 PM | Report abuse

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