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Does Green Tea Help Prevent Prostate Cancer?

“Prostate cancer is a leading cause of illness and death among men in the United States and Western Europe,” but rates in Asia can be as much as ten times lower. Perhaps Asians are genetically less likely to get prostate cancer? No. Japanese Americans and Chinese Americans have high prostate cancer rates as well, as you can see at 0:22 in my video Preventing Prostate Cancer with Green Tea. In the United States, up to nearly one in three men in their 30s already has small prostate cancers brewing and that grows to nearly two thirds of American men by their 60s. On autopsy, most older men were found to have unknown cancerous tumors in their prostates. What’s remarkable is that Asian men seem to have the same prevalence of these hidden, latent prostate cancers on autopsy, but they don’t tend to grow enough to cause problems. In Japan, men tend to die with their tumors rather than from their tumors. Of course, that’s changing as Asian populations continue to Westernize their diets.

What is it about Western diets that fuels cancer growth? It could be carcinogens in the diet accelerating the growth of cancer. Indeed, the typical American diet is rich in animal fats and meats, but it could also be something protective in Asian diets that is slowing the cancer growth, such as fruits, vegetables, soy foods, or green tea.

How might we determine if there is a link between tea consumption and the risk and progression of prostate cancer? Dozens of studies have examined whether tea drinkers tend to get less cancer in the future and if cancer victims tend to have drunk less tea in the past. Although the results have been mixed, overall, tea consumption was associated with a lower risk of prostate cancer. So, tea consumption might indeed play a protective role. However, just because tea drinkers get less cancer doesn’t mean it’s necessarily because of the tea. Perhaps drinking tea is just a sign of a more traditional lifestyle and maybe tea drinkers are less likely to be patrons of the thousand KFC fast-food restaurants now in Japan.

In vitro studies performed in a lab allow for as many factors to be controlled as possible. When everything is removed from the equation except for green tea and prostate cancer, dripping green tea compounds directly on prostate cancer cells in a petri dish can cause them to self-destruct, as you can see at 2:31 in my video. But we do not appear to absorb enough green tea compounds into our bloodstream to reach those kinds of levels. This may explain why some studies failed to find an association between tea drinking and cancer. Maybe we’re not drinking enough? In the United States, for example, the “high” tea-drinking group may be defined as more than five cups of tea a week. In Japan, however, the “high” tea-drinking group can consume five or more cups a day, which was associated with about halving the risk of aggressive prostate cancer. How? Apparently, it was not by preventing the formation of the cancer in the first place, but perhaps by slowing or stopping the cancer’s growth. If green tea can stop the growth of prostate cancer, why not try giving green tea to prostate cancer patients to see if it will help? Green tea is actually put to the test in cancer patients in my video Treating Prostate Cancer with Green Tea.

For more on men’s health, check out:

Interested in more on tea? See:

In health,
Michael Greger, M.D.

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Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, 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.

27 responses to “Does Green Tea Help Prevent Prostate Cancer?

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  1. ‘Dozens of studies have examined whether tea drinkers tend to get less cancer in the future and if cancer victims tend to have drank less tea in the past.’

    Ouch. It’s ‘have drunk’.

    1. Thank you! I was trying to decide if I should comment on this.

      ‘Have drank’ was also used in How Not to Diet. I wonder why these are not being proofread?

  2. My sweetheart worker passed away at almost 90 from Prostate Cancer. Dr. Ornish’s study niggled at me. He had a long, happy life, but he made the people around him smile and laugh and he was the type of person who showed up for his responsibilities every single day of his life. The world could have used another few decades with him.

    1. When they say 5 cups of tea are they the small cups they use at Asian restaurants?

      Versus the great big mugs that Americans tend to use?


      I know that the people who vote metrics would say to me that a rice cup not being a cup and a teacup being arbitrary is their whole point.

      I, on the other hand, am just laughing at the notion of 5 cups that went through my head.

      1. I find green tea to be an irritant to my bladder and can’t imagine what 5 cups daily would result in since my bathroom visits are already so frequent with just one large morning cup.

  3. I’m curious if the tea must be hot to receive the benefits? I make iced tea with green tea by putting tea bags in a mason jar with cold water and letting it sit overnight. Thoughts?

    1. I buy Gunpowder Green Tea by the kilogram off Ebay. It is very inexpensive. I use one cup of leaves to boil in 45 ounces of water (the size of a V8 bottle.)

      I add the same amount of hibiscus flower (thanks again Ebay,) which has even more anti-oxidant than green tea.

      I let it sit overnight, squish the water out of the leaves, and strain. I put it in the V8 bottle and refrigerate. Obviously it is super concentrated.

      I use it to make ice cubes to put in my drinking water. It could also be used to make “instant” hot tea.

      1. Sounds like a good routine (I alternate Gunpowder with Dragonwell as my day to day go to teas; I like Gunpowder but it also helps keep the price of my tea habit more reasonable). And not to be too persnickety but I found that the tea snobs had a point re. water temperature; when I tried cooler water (around 180-185 F) Gunpowder did taste better than if I used boiling water.

        1. Karly Young,

          I have an Oxo electric tea kettle with temperature control — and a little water temp guide for different kinds of tea and coffee, and it suggests brewing green tea at about 175 F. So I brew my tea at that temp, for 3 minutes. And I love the taste of the resulting tea, though my husband not so much. I drink one mug — about 12 oz — with breakfast.

          I also love the gooseneck pour spout of the kettle; I feel elegant pouring from it, and it’s easy to control how much I pour out. I use this kettle several times a day, to make tea and to make coffee in my AeroPress coffee maker.

          1. “And I love the taste of the resulting tea, though my husband not so much.”
            – – – – –

            So you don’t love the taste of your husband, huh Dr. J.? :-)

            (Sorry….couldn’t resist.)

            1. YR,

              Did I commit a grammatical faux pas?

              Sadly, he doesn’t care much for one and only cup of green tea I brewed for him — at about 175 F.

              As for the rest…hmmm, life is good.

          2. I have an Oxo electric tea kettle with temperature control
            Bought myself one of those glass water boilers for Christmas. Decided to try it for a cup of tea with tea bags. I noticed right away that some of my teas would actually brew stronger with room temperature water.

            I do brew with distilled water, both room temperature and freshly boiled. Anyway, going back to room temp brewing… unless I’m trying to get a second cup out of a tea bag.

            The hot water seems to work o.k. at wringing out that last little bit.

    2. I’m curious if the tea must be hot to receive the benefits?
      Hope not… I cold brew (well, room temperature ‘-) all the different teas I drink.

  4. I mix TEN powdered herbs together along with NAC and alpha-lipoic acid. I take about 500mg of the mix every morning. During the day I drink iced hibiscus / green tea.

    Imagine the synergism!

  5. Off topic, but I got this in one of those “pass-it-along” emails. Rather than just dismiss it out of hand I thought I would make it available to the NF.o jury to decide if it is relevant or no.

    Since many people are alone when they suffer a heart attack without help, the person whose heart is beating improperly and who begins to feel faint, has only about 10 seconds left before losing consciousness.
    7. However, these victims can help themselves by coughing repeatedly and very vigorously. A deep breath should be taken before each cough, and the cough must be deep and prolonged, as when producing sputum from deep inside the chest. A breath and a cough must be repeated about every two seconds without let-up until help arrives, or until the heart is felt to be beating normally again.
    8. Deep breaths get oxygen into the lungs and coughing movements squeeze the heart and keep the blood circulating. The squeezing pressure on the heart also helps it regain normal rhythm. In this way, heart attack victims can get to a hospital. …

      1. Wow, thanks Quickdraw. I’ll try and pick out the relevant points from your link and paste them below:

        “Those kindhearted souls who started it on its way likely had no inkling the advice they were forwarding could potentially be harmful to someone undergoing a heart attack, but that is indeed the case.

        If you knew exactly what you were doing, this procedure might help save your life. If, however, you were to attempt cough CPR at the wrong time (because you misjudged the kind of cardiac event being experienced) or went about it in the wrong way, it could make matters worse.

        Cough CPR is not a new procedure: it has been around for years and has been used successfully in isolated emergency cases where victims realized they were on the verge of fainting and about to go into full cardiac arrest (their hearts were about to stop) and knew exactly how to cough so as to keep enough oxygen-enriched blood circulating to prevent them from losing consciousness until help could be sought, or they were under the direct care of physicians who recognized the crises as they were taking place and were on hand to instruct patients step by step through the coughing. Even were the afflicted to correctly recognize they were experiencing the sort of cardiac event where cough CPR could help, without specific training to hit the right rhythms their coughing could turn mild heart attacks into fatal ones.

        Although the text of the e-mailed advice was published in a newsletter put out by Mended Hearts (a support group for heart disease patients and their families), that organization has since disavowed it and has a page on its web site asking readers not to heed the advisory. The piece on cough CPR found its way into that publication through a blend of too much enthusiasm and a dearth of fact checking. From there, other chapters picked it up, spreading the notion to an even wider audience. Attempts now to distance the organization from it don’t begin to undo the damage done by the piece having been picked up from there.

  6. I wonder if it’s not the tea but the fact that they consume much less dairy! After all we know that there is a strong link between high levels of dairy consumption and prostate cancer!

  7. Boil the water, let it cool for 3 minutes, brew the tea for 3 minutes. Before I discovered this trick I disliked very much the tinny taste of green tea. Now I find it delicious and drink it and Oolong made by the same method daily.

  8. My husband was an avid green tea drinker of different varieties for 10 years before being diagnosed with prostate cancer. His mistake was having escalating PSA numbers and for some reason quit going to the doctor.
    The tea may have helped in some capacity, but it certainly isn’t a cure. The cancer is slow growing at first, but once it metastasized it was like a wildfire. The pain was horrendous. Life cut short in early 70s.

  9. Drink, drank, drunk. Whatever. I gave up coffee for green tea—because I think green tea is better. I will put matcha green tea in a cup along with unsweetened cocoa powder and cinnamon powder and maybe a Bengal (chai) tea bag. This is a strong mix and I might drink two or three cups a day in the winter.

  10. Dear Dr. Greger,

    Thank you for putting forth all of this research. I have read your articles and supporting documentation and have a question.

    At the end, you site a study that gave green tea to people with prostate cancer.

    This study found that only 1 person of the 42 patients found benefit, but the benefit did not last longer than 2 months. Most patients got green tea toxicity which included nausea, insomnia, fatigue, diarrhea, abdominal pain… ect.

    Do you really think this is strong evidence that green tea should be publicized as a food that can reduce prostate cancer risk or improve prostate cancer once it occurs? Your article makes people feel like green tea is the cure, but this research suggests otherwise. Do you genuinely believe green tea is a cure to prostate cancer and it is right to make people think such is true?

    Quoting the study:
    Tumor response, defined as a decline >/= 50% in the baseline PSA value, occurred in a single patient, or 2% of the cohort (95% confidence interval, 1-14%). This one response was not sustained beyond 2 months. At the end of the first month, the median change in the PSA value from baseline for the cohort increased by 43%. Green tea toxicity, usually Grade 1 or 2, occurred in 69% of patients and included nausea, emesis, insomnia, fatigue, diarrhea, abdominal pain, and confusion. However, six episodes of Grade 3 toxicity and one episode of Grade 4 toxicity also occurred, with the latter manifesting as severe confusion.”

    The rest of the studies look at Asians vs Caucasions. it is interesting that asian men have less prostate cancer, but it doesn’t seem like many factors are being account for. Why is sugar intake not being accounted for here? It seems like the other papers look at the two groups, then only look at green tea, see an effect, and credit the green tea. Meanwhile, since there are an almost unlimited amount of potential confounding factors, it feels incorrect to me to say ‘it may be the green tea’ without controlling for at least exercise, diet, smoking, or any other healthful behavior.

    Thanks again for writing this blog.

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