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Groene thee voorkomt prostaatkanker.*
Groene thee kan de kans op prostaatkanker wel tot
90% verkleinen blijkt een kleine studie.
Gedurende een jaar kregen proefpersonen, allemaal
mannen met een groot risico op prostaatkanker, groene thee extracten (3x daags
200 mg) of een placebo. Na een jaar bleek dat in de “groene thee”groep
slechts 1 persoon prostaatkanker had en in de placebo groep 9 mannen.
De gebruikte hoeveelheid extract komt overeen met
12-14 koppen groente thee per dag.
Green Tea Prevents
Prostate Cancer in High-Risk Men
Researchers believe beverage's catechins have powerful antioxidant
properties
A supplement
containing antioxidants from green tea was 90 percent effective in
preventing prostate cancer in men at high risk for the disease.
That's the
conclusion of an Italian study that found after a year of taking green tea
catechins, only one man in a group of 32 who were at higher risk of prostate cancer actually developed the disease, while nine men in a
group of 30 high-risk men who took a placebo developed prostate cancer.
"To our
knowledge, this is the first study showing that green tea catechins (GTC) have
potent chemoprevention activity for human prostate cancer," said study
author Saverio Bettuzzi, an associate professor of biochemistry in the School of
Medicine at the University of Parma in Italy.
Findings from the
study were presented at the American Association for Cancer Research annual
meeting, in Anaheim, Calif.
Other than skin cancer, prostate cancer is the most common cancer affecting
men. More than 230,000 American men are diagnosed with this disease each year,
according to the American Cancer Society. Since many prostate cancers are found
in their early stages, about 99 percent of those diagnosed can expect to live at
least five years, while up to 92 percent survive for at least 10 years after
their diagnosis. However, prostate cancer can be deadly. The disease claims the
lives of more than 30,000 men in the United States annually, making it the
second largest cancer killer in men.
Bettuzzi explained
that while other studies, including his own previous work, had shown that green
tea could inhibit prostate cancer cell growth in laboratory models, the
researchers wanted to know if it would work in humans.
They recruited 62
men at high risk of developing prostate cancer because they already had
precancerous lesions, which often turn into cancer within a year.
The men were
between the ages of 45 and 75. The researchers excluded vegetarians because they
may already have a lower risk of developing prostate cancer, men who already
consumed green tea, and men taking antioxidant supplements or hormone therapy.
Thirty two of the
men were asked to take a 200-milligram pill containing green tea catechins three
times daily for a year; the other 30 men were given a placebo.
Biopsies were
conducted at six months, and then again a year later.
Remarkably, only
one man in the treatment group was diagnosed with prostate cancer, while nine
men in the control group developed the disease.
"A projection
of our data suggests that up to 90 percent of chemoprevention efficacy could be
obtained by GTC administration in men prone to developing prostate cancer such
as the elderly, African-Americans and those with a family history of prostate
cancer," Bettuzzi said.
However, Bettuzzi
isn't recommending that men start treating themselves with green tea or green
tea supplements. He said to consume an amount equivalent to that used in the
study, you would have to drink 12 to 15 cups of tea daily, and that while
supplements are commercially available, their quality cannot be assured and they
may contain caffeine, or more alarmingly, pesticides or other contaminants.
"This is a
very interesting observation that deserves to be studied further," said Dr.
Jay Brooks, chairman of hematology and oncology at the Ochsner Clinic Foundation
Hospital in New Orleans. But, he added, "Personally, I am not recommending
that my patients do this."
Bettuzzi also said
his findings need to be confirmed in a larger study.
In the meantime,
Brooks said that if you're concerned about prostate cancer, be sure you maintain
a healthy body weight because obesity
increases your risk. And, he said, make sure you go to your doctor for proper prostate cancer screening.
In other prostate
cancer news presented at the same meeting, researchers from the Fox Chase Cancer
Center in Philadelphia announced that the trace mineral selenium, in combination
with other cancer-fighting agents, may make an even more powerful therapy. When
a selenium metabolite, dubbed MSA, was combined with a chemotherapy known as TRAIL, more cancer cells underwent
self-inflicted cell death (apoptosis). TRAIL alone can induce apoptosis in
malignant cells, but some cancer cells are resistant to this therapy.
"The combination of TRAIL and MSA may be a novel strategy for the development of innovative therapeutic modalities targeting apoptosis-resistant forms of prostate cancer," said lead researcher Dr. Vladimir Kolenko.( Mei 2005)