Treating Prostate Cancer with Green Tea

Green tea has been called nature’s defense against cancer. Population studies linking green tea consumption with lower cancer risk have led some to advocate for the incorporation of green tea into the diet “so as to fully benefit from its anticarcinogenic properties.” What, after all, is the downside?

But, population studies can’t prove cause and effect. Indeed, “it is not possible to determine from these population-based studies whether green tea actually prevents cancer in people”…until it is put to the test.

Prostate cancer is preceded by a precancerous condition known as intraepithelial neoplasia. You can see a graphic of the progression at 0:41 in my video Treating Prostate Cancer with Green Tea. Within one year, about 30 percent of such lesions turn into cancer. Because no treatment is given to patients until cancer is diagnosed, this presents a perfect opportunity to try green tea. In the study, 60 men with precancerous prostate intraepithelial neoplasia were randomized into either a green tea group or a placebo group. Since it’s hard to make a convincing placebo tea, the researchers used green tea pills that were roughly equivalent to about six cups of green tea a day and compared them to sugar pills. Six months into the study, they took biopsies from everyone. In the placebo group, 6 of the 30 men developed cancer by the halfway point and 3 of the remaining 24 developed it by the end of the year. So, 9 out of 30 in the placebo group, about 30 percent, developed cancer within the first year, which is what normally happens without any treatment. In the green tea group, however, none of the 30 men developed cancer within the first six months and only one developed it by the end of the year. Only 1 out of 30 is nearly ten times less than the placebo group. This marked the first demonstration that green tea compounds could be “very effective for treating premalignant lesions before [prostate cancer] develops.” Even a year later, after the subjects stopped the green tea, nearly 90 percent of the original green tea group remained cancer-free, while more than half of the placebo group developed cancer, as you can see at 2:09 in my video. This suggests that the benefits of the green tea may be “long-lasting,” with an overall nearly 80 percent reduction in prostate cancer.

What if you already have prostate cancer? A proprietary green tea extract supplement was given to 26 men with confirmed prostate cancer for an average of about a month before they had their prostates removed, and there was a significant reduction in a number of cancer biomarkers such as PSA levels, suggesting a shrinkage of the tumor. However, there was no control group, and the study was funded by the supplement company itself. When an independent group of researchers tried to replicate the results in a randomized, double-blind, placebo-controlled trial, they failed to find any statistically significant improvement. Perhaps green tea is only effective in the precancerous state and not powerful enough “to meaningfully impact overt prostate cancer”?

It certainly didn’t seem to help for advanced metastatic cancer in the two studies that tried it. What’s more, doubt has recently been cast on the precancerous results. When researchers tried to replicate it, the green tea extract group only seemed to cut prostate cancer development about in half, which very well may have happened just by chance, given the small number of people in the study. So where does that leave us?

Unfortunately, green tea extract pills are not without risk. There have been about a dozen case reports of liver damage associated with their use. Until there’s more solid evidence of benefit, I’d stick with just drinking the tea. Green or black? A recent study that randomized about a hundred men with prostate cancer to consume six cups a day of green tea or black tea found a significant drop in PSA levels and NF-kB in the green tea group, but not in either the black tea or control groups, as you can see at 4:12 in my video. NF-kB is thought to be a prognostic marker for prostate cancer progression, so the green tea did appear to work better than the black tea.


What happens if we pack our diet with all sorts of plant foods? See my Cancer Reversal Through Diet? video.

Before and after: Learn about Preventing Prostate Cancer with Green Tea and Changing a Man’s Diet After a Prostate Cancer Diagnosis.

Similar studies were done with pomegranates. I discuss the results in Pomegranate vs. Placebo for Prostate Cancer.

Interested in other ways to prevent or treat prostate cancer? See:

What about green tea and other types of cancer? Check out:

For more on some of green tea’s other benefits, see:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

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 drank 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.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Sparkling or Still Water for Stomach Upset and Constipation?

“Natural bubbling or sparkling mineral waters have been popular for thousands of years,” but manufactured sparkling water was first “‘invented’ in the mid to late 1700s” when a clergyman suspended water over a vat of fermenting beer. “For centuries, carbonated water has been considered capable of relieving gastrointestinal symptoms, including dyspepsia,” or tummy aches. But we didn’t have good data until a study was published in 2002, which I discuss in my video Club Soda for Stomach Pain and Constipation. Twenty-one people with dyspepsia, which was defined in the study as “pain or discomfort located in the upper abdomen” including bloating, nausea, and constipation were randomized to drink one and a half quarts of either carbonated or tap water every day for two weeks.

Carbonated water improved both dyspepsia and constipation compared to tap water. “Drink more water” is a common recommendation for constipation, but researchers didn’t observe a clear benefit of the added tap water. It seems you need to increase fiber and water rather than just water alone, but sparkling water did appear to help on its own. The study used a sparkling mineral water, though, so we can’t tell whether these effects were due to the bubbles or the minerals.

There’s been a concern that carbonated beverages may increase heartburn and GERD, acid reflux disease, but that was based on studies that compared water to Pepsi cola. Soda may put the pepsi in dyspepsia and contribute to heartburn, but so may tea and coffee in those who suffer from heartburn. That may be partly from the cream and sugar, though, since milk is another common contributor to heartburn. Carbonated water alone, though, shouldn’t be a problem.

Similarly, while flavored sparkling drinks can erode our enamel, it’s not the carbonation, but the added juices and acids. Sparkling water alone appears 100 times less erosive than citrus or soda. So, a sparkling mineral water may successfully help treat a stomach ache and constipation without adverse effects, unless you’re the teenage boy who opened a bottle of sparkling wine with his teeth or the nine-year-old boy who tried to do so on a hot day after he’d shaken it up, actions placing them at risk for a pneumatic rupture of the esophagus.


For more on combating acid reflux, see Diet and GERD Acid Reflux Heartburn and Diet and Hiatal Hernia.

Some of my other videos on beverages include:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations: