Green tea boosts production of detox enzymes, rendering cancerous chemicals harmless

Posted on: August 11, 2007

Concentrated chemicals derived from green tea dramatically boosted production of a group of key detoxification enzymes in people with low levels of these beneficial proteins, according to researchers at Arizona Cancer Center.

These findings, published in the August issue of Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research, suggest that a green tea concentrate might help some people strengthen their metabolic defense against toxins capable of causing cancer.

In a study of 42 people, the concentrate − composed of chemicals known as green tea catechins in amounts equal to that found in 8-16 cups of green tea − boosted production of the enzymes, which belong to the glutathione S-transferase (GST) family, by as much as 80 percent in some participants.

GST enzymes are believed to be crucial to the body’s defense against cancer-causing chemicals and other toxins, according to the study’s lead investigator, H.-H. Sherry Chow, Ph.D., a research associate professor at the University of Arizona. They modify the cancer-causing molecules that would otherwise damage cellular DNA, thus rendering them inert.

“They actually convert known carcinogens to non-toxic chemicals, and studies have shown a correlation between deficient expression of these enzymes and increased risk of developing some cancers,” Chow said.

“Expression of this enzyme varies dramatically in people due to genetic variation and environmental factors,” Chow added. “Green tea catechins somehow increase gene expression of these enzymes, which can be an advantage to people with low levels to start with.”

Green tea has long been of interest to researchers given studies that have shown populations in which it is often consumed, such as the Chinese and Japanese, generally have lower rates of cancer. To find out if green tea can protect against cancer, the NCI has sponsored a number of rigorous scientific studies testing capsules of the extract, Polyphenon E, that have been prepared in Japan to meet exact specifications. These pills contain epigallocatechin gallate (EGCG), a catechin known for its potent antioxidant activity, and are currently being tested against a variety of cancers in clinical trials.

This study was designed to see if green tea catechin concentrate had any effect on the levels of GST enzymes in healthy individuals − research that could explain the tea’s anti-cancer properties. Healthy volunteers were asked to abstain from consuming any tea or tea-related products for four weeks. At the end of this “washout period,” blood was drawn and baseline GST enzyme levels were determined for each participant. Then, the volunteers were asked to take four Polyphenon E capsules, for a total of 800 milligrams of EGCG, each morning on an empty stomach for four weeks and to abstain from drinking tea or eating many cruciferous vegetables, which contain other beneficial chemicals. Another blood sample was taken after four weeks, and GST activity was determined.

Researchers found that use of Polyphenon E enhanced GST activity when data from all participants were included for analysis. But it had its most significant effect in volunteers whose baseline blood measurements showed low GST activity − an 80 percent increase compared to baseline GST activity. Activity did not change in volunteers with medium GST expression, or in those with the highest levels, GST seemed to decrease slightly although researchers believe that decline was due to random variation.

“This is the first clinical study to show proof that chemicals in green tea can increase detoxification enzymes in humans,” Chow said. “There may be other mechanism in play by which green tea may protect against cancer development, but this is a good place to start.”

source:  American Association for Cancer Research 


24 Responses to "Green tea boosts production of detox enzymes, rendering cancerous chemicals harmless"

Well then, maybe I should get used to drinking green tea rather than black.

This is great stuff! Thanks for sharing! (((((HUGS))))) sandi

[…] Green tea boosts production of detox enzymes, rendering cancerous chemicals harmless Concentrated chemicals derived from green tea dramatically boosted production of a group of key detoxification enzymes […] […]

The benefits of tea are amazing…new info coming out everyday! I wish there were more TEA blogs! :)

[…] first would be Biosingularity as it featured a health tidbit regarding the benefits of green tea in the fight against the Big C. Sure it might sound like one of those overused marketing lines by […]

Does it count if I put bags of green tea on my eyes? It makes them look so radiant.

I have always loved green tea drink after each meal generaly and also in the morning you just get used to it ..but I still every now and then can’t help but have black tea with milk

I can’t stand green tea, but this study was based on extract. Is that correct?

[…] Now, I drink green tea, and I’m so glad it’s actually good for you… […]

I love tea of all kinds, but I’m very glad now! I have two boxes of green tea in my cupboard at this very moment.

I’m going to miss my Earl Grey, though…

Funny I came across this post when I am actually sitting in the Arizona Cancer Center (where I work). Its gratifying to see basic research translate to real things that the average person can do and benefit from. It would be relevent to know how much green tea 800mg or EGCG is equivalent to. I have a feeling it may be in the gallons!

Mysterbea – I think that would be equivalent of between 5-10 cups of green tea, depending on brand and brewing. See here for further info :

In fact most studies show great benefit of green tea over 5 cups a day, so it is probably within this range.

Thank you, I respectfully stand corrected! I tried to do a quick search to find the info but was unsuccessful. I do think that that is important information for everyone those who want to consume green tea for the health benefits.

It should be mentioned that green tea can contain reasonably large amounts of flouride which may or may not be important to you. I personally try to eliminate it from my diet. There are liquid purified green tea extracts available that may be a better choice.

Green tea is very much useful to me.It makes me very much refreshed all through the day.i personally feel that people on diet should take a cup of green tea as beverage everyday.This will keep the metabolism rate very high.The information provided is very useful to every one who drink tea.

Yeah green tea is my favourite and i drink everyday.

“Green tea has long been of interest to researchers given studies that have shown populations in which it is often consumed, such as the Chinese and Japanese, generally have lower rates of cancer.”

is this due to green tea or could there be another element, not yet considered, that affects cancer?

This tea is also my personal favourite. It dos help us to detox.

[…] with low levels of these beneficial proteins, according to researchers at Arizona Cancer more | digg […]

I’m not sure where’s green tea from between china and japan but it has been consumed for 4000 – 5000 years. Now it’s popular around the world. Ice tea isn’t better result than hot tea. I like it. :)

Inspiring articles, I believe consuming green tea regularly with appropriate dose will make our body better. Beside, it contain antioxidant

Nice posting


Thank you for sharing these interesting fact! The antioxidant elements present in green tea helps in getting rid of toxic in the body. No wonder I feel good and refreshing after drinking green tea. :)

I love green tea, and now that I know how good it is for you I’ll certainly be drinking it a lot more. Might try the kids on it too. Great article.


The benefits of drinking green tea simply cannot be ignored. Wether you drink it for a specific reason or just for all round good health, it is a wonder tea. thank you for posting this info.

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