Can Green Tea Help Prevent Cancer?

Tea consumption is associated with a reduced risk of [heart disease], stroke,” and premature death in general, with each additional cup of green tea a day associated with a 4% lower mortality risk. So, maybe, “drinking several cups of tea daily can keep the doctor away”—as well as the mortician. But, what about cancer?

“There is growing evidence from laboratory, [population], and human intervention[al] studies that tea can exert beneficial disease-preventive effects,” and further, may actually “slow cancer progression.” Let’s review some of that evidence.

Not only do those who drink a lot of tea appear to live years longer than those who drink less; drinking lots of tea may delay the onset of cancer. Now, these are in Japanese tea cups, which only contain half a cup; so, the highest category here is greater than or equal to five full cups of tea, not ten. The women that did get cancer appeared to get it seven years later if they had been drinking lots of tea compared to those who consumed less, whereas men had a three-year delay, the difference male versus female due, potentially, to their smoking habits.

Green tea may be able to interfere with each of the stages of cancer formation: the initiation of the first cancer cell, promotion into a tumor, and then, the subsequent progression and spread. Cancer is often initiated when a free radical oxidizes our DNA, causing a mutation. But within 40 minutes of drinking green tea, you can get a nice “spike” in the antioxidant power of your bloodstream. “This increase…, in turn, [may] lower oxidative damage to DNA and so decrease [the] risk of cancer.”

Furthermore, in terms of “genoprotective effects”—protecting our genes—”pre-existing oxidation-induced DNA damage was…lower” after drinking green tea, suggesting that it can boost DNA repair as well. But, we didn’t know for sure, until now.

There’s a DNA-repair enzyme in our body called OGG1, and within one hour of drinking a single cup of green tea, we can boost its activity—though after a week of tea drinking, we can boost it even higher. So, “regular intake of green tea [may have] additional benefits in the prevention and/or repair of DNA damage.” Tea is so DNA-protective, it can be used for sperm storage for fresh samples until they can be properly refrigerated.

And so anti-inflammatory, it can be used for pain control as a mouthwash after wisdom tooth surgery. And, in terms of controlling cancer growth, at a dose of green tea compounds that would make it into someone’s organs after drinking six cups of tea, it can cause cancer cells to commit suicide—apoptosis (programmed cell death)—while leaving normal cells alone.

There’s lots of chemo agents that can kill cancer through brute force. But, that can make normal cells vulnerable too. So, “green tea appears to be potentially an ideal agent” for cancer prevention: “little or no adverse side effects,” efficacious for multiple cancers “at achievable dose levels,” and can be taken orally.

We have a sense of how it works: by stopping cancer cells from growing and causing them to off themselves. It’s cheap and has a history of safe, acceptable use. But this was all based on in vitro studies in a test tube. It needs to be evaluated in human trials: give people with cancer green tea to see if it helps—which we’ll explore, next.

Doctor’s Note

Sorry about the cliffhanger! I just wanted to offer a good backgrounder on the antioxidant and anti-inflammatory activities. Stay tuned for Can Green Tea Help Treat Cancer?

You don’t have to wait for info on prostate cancer, though. See my recent videos: Preventing Prostate Cancer with Green Tea and Treating Prostate Cancer with Green Tea.

I also have a few older videos:

That wisdom tooth thing is so interesting. It can also just be used as an anticavity mouth rinse (see What’s the Best Mouthwash?).

Is Caffeinated Tea Dehydrating? Watch the video!

If you haven’t yet, you can subscribe to my videos for free by clicking here.

In health,

Michael Greger, M.D.

Michael Greger, M.D., is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous “meat defamation” trial. Currently Dr. Greger proudly serves as the Director of Public Health and Animal Agriculture at the Humane Society of the United

Foods That May Block Cancer Formation

Foods That May Block CancerMore than 85% of breast cancers are sporadic and attributable to long-term exposure to environmental carcinogens, such as those in the diet, through a multistep disease process progressing from non-cancerous to pre-cancerous to malignant stages. How can we interrupt this process?

The chemical carcinogens formed in chicken, fish and other meats during cooking that I profiled in my last two posts Estrogens in Cooked Meat and Avoiding Cooked Meat Carcinogens are so effective at transforming normal human breast cells into breast cancer cells that researchers have used it as a model of cancer formation to test out various plant-based interventions. Visualize the Jekyll to Hyde breast cancer transformation here.

For example, three recent meta-analyses (compilations of individual studies) reviewing all the epidemiological (population-based) evidence concerning green tea consumption and breast cancer risk concluded that green tea consumption may be protective. Well, now researchers can put it to the test. See my 3-min. video Cancer, Interrupted: Green Tea to see what green tea can do to block the transition towards breast cancer caused by the cooked meat carcinogens.

More on the chemicals formed by exposing mammal/fish/bird muscles to high temperatures:

Any other feats green tea can pull off? See Treating Genital Warts With Green Tea and Treating Gorlin Syndrome With Green Tea.

Might white tea work even better? See Antimutagenic Activity of Green Versus White Tea.

Any other plants that might be able to smack on the cancer kibosh (besides broccoli of course: DNA Protection from Broccoli and Broccoli Versus Breast Cancer Stem Cells)? What about garlic? Watch my 4-min video Cancer, Interrupted: Garlic & Flavonoids to find out.

Should garlic be raw or cooked? See How can I preserve the anti-cancer effects of cooked garlic? I’ve previously profiled garlic in #1 Anticancer Vegetable (make sure to also watch its “prequel” Veggies vs. Cancer).

Other foods that may protect DNA include kiwifruit (Kiwifruit and DNA Repair), cruciferous vegetables (DNA Protection from Broccoli), leafy vegetables (Eating Green to Prevent Cancer), and plants in general (Repairing DNA Damage).

What other dietary changes should we consider after a cancer diagnosis? See:

Michael Greger M.D.About Michael Greger M.D.Michael Greger, M.D., is a physician, author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous “meat defamation” trial. Currently Dr. Greger proudly serves as the Director of Public Health and Animal Agriculture at the Humane Society of the United States.

Cancer, Interrupted: Green Tea

Green Tea For Breast Cancer
By: Michael Greger, M.D. NutritionFacts.org.

Using the cooked meat carcinogen PhIP to turn normal breast cells cancerous, researchers explore the use of green tea to interrupt this malignant transformation.

More than 85% of breast cancers are sporadic and attributable to long-term exposure to environmental carcinogens, such as those in the diet, through a multistep disease process progressing from non-cancerous to premalignant and malignant stages.

Now we know that the chemical carcinogen (PhIP) is one of the most abundant heterocyclic amines found in high-temperature cooked meats and is recognized as a breast carcinogen. However, the PhIP’s mechanism of action in breast cell carcinogenesis is not clear.

How does it do it? Well in this landmark new study they “demonstrated, for the first time, that cumulative exposures to PhIP at effectively induced progressive carcinogenesis, cancer transformation of human breast cells from a non-cancerous stage to premalignant and malignant stages in a dose- and exposure-dependent manner.” They started out with normal human breast cells. And were able to transmute them completely into cancer cells just using that cooked meat carcinogen found predominantly in fried bacon, fish, and chicken. That’s all it took, and Jekyll becomes Hyde.

Now PhIP was already established as a carcinogen, the reason they did this was to develop a model of ”human breast cancer carcinogenesis”, from beginning to end to test various interventions to see if we can somehow stop this process of cancer formation. For example, three recent meta-analyses reviewing all the epidemiological, or population-based evidence concerning green tea consumption and breast cancer risk concluded that green tea consumption may be protective.

Well let’s put it to the test. Here’s the response of normal breast cells to repeated exposure to the cooked meat carcinogen PhIP using six different measures of cancerous qualities. They all go up—but, if you add a little green tea phytonutrients, the transformation to breast cancer is blunted, it was indeed “effective in suppressing PhIP-induced cellular carcinogenesis and tumorigenicity.”

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by Jonathan Hodgson

Doctor’s Note

What is this PhIP stuff? See the last four videos for some background:

Any other feats green tea can pull off? See Treating Genital Warts With Green Tea and Treating Gorlin Syndrome With Green Tea.Might white tea work even better? See Antimutagenic Activity of Green Versus White Tea.Any other plants that might be able to smack on the cancer kibosh? (I mean besides broccoli, so for example: DNA Protection from Broccoli and Broccoli Versus Breast Cancer Stem Cells). Stay tuned for my next video Cancer, Interrupted: Garlic & Flavonoids.Please also check out my associated blog post for more context:  Foods That May Block Cancer FormationIf you haven’t yet, you can subscribe to my videos for free by clicking here.PS: Those of you with mobile devices will have noticed immediately the major upgrade to NutritionFacts.org yesterday. The entire site has been redesigned to incorporate “responsive web design.” This means NutritionFacts.org will now automatically resize to fit whatever device you’re on. There are now close to 50 million people in the U.S. alone that watch videos on their mobile devices. Sure we could make a special iphone app, an ipad app, an android app, but there are now thousands of smartphones and tablets out there. Enter: responsive web design. NutritionFacts.org now automatically resizes to fit your screen–any screen! Try resizing your browser right now. See? Isn’t that cool?! Thanks go to our resident web designer genius Christi Richards and the generous support of The Jesse and Julie Rasch Foundation, without which NutritionFacts.org wouldn’t even exist.

Michael Greger M.D.About Michael Greger M.D.
Michael Greger, M.D., is a physician, author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous “meat defamation” trial. Currently Dr. Greger proudly serves as the Director of Public Health and Animal Agriculture at the Humane Society of the United States.

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