Treating Prostate Cancer with Green Tea

Treating Prostate Cancer with Green Tea

September 14, 2019 51 By Ewald Bahringer


“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— after all, what’s the downside? However, population studies
can’t prove cause and effect. It’s not possible to determine whether green tea actually prevents cancer in people,
until you put it to the test. Prostate cancer is preceded by a precancerous
condition known as intraepithelial neoplasia. Within 1 year, about 30% of
such lesions turn into cancer. Because no treatment is given to
patients until cancer is diagnosed, what a perfect opportunity to try green tea. So, 60 men with precancerous prostate intraepithelial
neoplasia were randomized into either a green tea group
or a placebo group. It’s hard to make a convincing placebo tea;
so, they used green tea pills— roughly equivalent to about
6 cups of green tea a day— compared to sugar pills. Six months into the study, they took biopsies
from everyone, and in the placebo group, 6 of the 30 developed
cancer by the halfway point, and then 3 of the remaining 24
by the end of the year. So, 9 out of 30 in the placebo group developed
cancer or 30%, which is what normally happens
when you don’t do anything: about 30% go on to develop cancer
within the first year. But, in the green tea group, none developed
cancer within the first 6 months, and only 1 by the end of the year. So, only one out of 30, nearly ten times
less than the placebo group: the first demonstration that green tea compounds
could be very effective for treating premalignant lesions
before prostate cancer develops. And, even a year later, after they
stopped the green tea, nearly 90% of the original green tea
group remained cancer free, while more than half of the
placebo group developed cancer. This suggests that the benefits of
the green tea may be long lasting, overall a nearly 80% reduction
in prostate cancer. That is pretty impressive. 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, but 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. So, maybe green tea is only effective
in the precancerous state but not powerful enough to impact
overt prostate cancer. Certainly didn’t seem to help for advanced
metastatic cancer in the two studies that tried it. And recently, doubt has 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, because of the small number of
people in the study may very well have happened just by chance. So, where does that leave us? Unfortunately, green tea extract pills are
not without risk— there’s been about a dozen case reports
of liver damage associated with their use; and so, until there’s more solid evidence
of benefit I’d stick with just drinking the tea. OK, green or black? A recent study that randomized about a hundred
men with prostate cancer to consume 6 cups a day of green or black tea found a
significant drop in PSA levels and NF-kB in the green tea group but not the
black tea or control groups. NF-kB is thought to be a prognostic marker
for prostate cancer progression; and so, the green tea appeared to work better
than the black.