THURSDAY, Oct. 18 (HealthDay News) -- Six cups of green tea a
day may slow the progression of prostate cancer, a new study
The finding stems from research that showed prostate patients
scheduled for a type of surgery known as a prostatectomy, where the
prostate is removed, reduced their levels of some
disease-associated inflammation by drinking lots of brewed green
tea in the weeks preceding the operation. And that reduction in
inflammation may inhibit tumor growth, the researchers
Their results were to be presented Thursday at the American
Association for Cancer Research's annual prevention conference in
The notion that the polyphenol compounds found in green tea
might have a protective effect against prostate cancer has yet to
be confirmed outside a laboratory setting. However, this latest
report builds on previous Italian research that suggested that
consuming green tea extract may help lower the risk that a
precancerous condition will develop into full-blown prostate
And related research that was also presented at the cancer
research conference suggested that the flavonoids found in fruits
and vegetables may be associated with a lower risk of developing
aggressive prostate cancer.
However, at least one urologist, Dr. Mark Soloway, chairman
emeritus of urology at the University of Miami Miller School of
Medicine, pointed to the new study's limitations, and said it was
too soon to say that green tea had any impact on prostate
Scientific findings presented at meetings should be viewed as
preliminary until published in a peer-reviewed journal.
In this latest green tea study, men who drank the beverage for
three to eight weeks prior to surgery experienced a noticeable drop
in both serum prostate-specific antigen (PSA) concentrations and
PSA protein expression by the time they went under the knife. The
fall-off in such telltale signs of disease was accompanied by
reductions in both disease-linked inflammation and oxidative DNA
damage, the study authors said.
"To see this effect, you would need to drink a lot of green tea," stressed study author Susanne Henning, a registered dietician and adjunct professor with the University of California, Los Angeles David Geffen School of Medicine. "Two cups a day is not going to help. In fact, we had our men drink six cups spread out all throughout the day, which I think was beneficial because green tea polyphenols are excreted very rapidly, so if you drink it that way you keep your levels up. And that seems to be the important factor in keeping the protection going."
To explore the anti-cancer potential of green tea, the authors
focused on 67 prostate cancer patients, all of whom were weeks away
from surgery. About half the men were randomly assigned to a
six-cup-a-day regimen of green tea leading up to surgery, while the
others consumed water instead.
The result: Blood and urine samples analyzed alongside tissue
samples taken during surgery revealed that the green tea group
fared significantly better on key signs of inflammation, PSA levels
and expression and DNA damage.
However, no notable difference was found between the two groups
in terms of tumor cell growth.
Henning stressed the need for more research on the potential
green-tea/prostate cancer connection, and her team is currently
planning new animal investigations involving combinations of green
tea and other natural foods.
While this research showed an association between green tea and
prostate cancer, it did not prove a cause-and-effect link.
"Actually, several food agents have been under investigation for their protective impact," she noted. "Lycopene and omega-3 fatty acids, for example. So, I would say that if you have cancer and you want to make a decision about all of this, then think of incorporating all of those as a part of a lifestyle change. I know that if I was diagnosed with prostate cancer, I would try to change my lifestyle. And that would mean, in addition to eating lots of fruits and vegetables and trying to lose weight and exercising, that I would definitely drink green tea."
The University of Miami's Soloway said that while drinking green
tea probably does not have a downside, this "limited study" does
not confirm its impact as a prostate cancer intervention.
"[There's] not much solid data to prove it," he said. "This is a small study, and it would take a longer study with hundreds of patients to 'prove' its benefit."
Soloway also noted that the jury is still out on whether
inflammation even plays a significant role in cancer development.
"It is very much a question," he said. "Not proven at all."
But, he agreed that until larger studies come along to explore
green tea's potential, "it might be worth giving it a shot."
For more on prostate cancer risk, visit the
American Cancer Society.
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