(Photo courtesy of BBC News)
A chemical found in GREEN TEA appears to slow the progression of PROSTATE CANCER, a study has suggested.
The research, in the US journal Cancer Prevention Research, found a significant fall in certain markers which indicate cancer development.
A UK charity said the tea might help men manage low-risk tumours. This could mean completely avoiding, in some cases, any of the more usual medical interventions and their associated side effects
Although previous studies have shown benefits from drinking green tea - including some positive findings in relation to prostate cancer, there have been mixed results.
Green tea has been linked to a positive effect on a wide range of conditions, including heart disease, cancer and Alzheimer's disease.
In this study, Philadelphia-based researchers tested a compound called Polyphenon E.
They were looking for a number of biomarkers - molecules - including vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) which are indicators of developing cancer.
They also looked for prostate specific antigen (PSA) - a protein only found in the prostate. Levels can rise if cancer is present.
The study included 26 men, aged 41 to 72 years, who had been diagnosed with prostate cancer and who were scheduled for radical prostate surgery.
Patients took four capsules containing Polyphenon E for an average of 34 days, up until the day before surgery - the equivalent of around 12 cups of normally brewed concentrated green tea.
The study found a significant reduction in levels of HGF, VEGF and PSA, with some patients demonstrating reductions of more than 30%.
Dr James Cardelli, from the Feist-Weiller Cancer Center, who led the study, said the compound, which was provided by the company Polyphenon Pharma, "may have the potential to lower the incidence and slow the progression of prostate cancer." There were only a few reported side effects associated with this study, and liver function remained normal.
Dr Cardelli said:
"We think that the use of tea polyphenols alone or in combination with other compounds currently used for cancer therapy should be explored as an approach to prevent cancer progression and recurrence.John Neate, chief executive of the Prostate Cancer Charity, said:
There is reasonably good evidence that many cancers are preventable, and our studies using plant-derived substances support the idea that plant compounds found in a healthy diet can play a role in preventing cancer development and progression."
"There have been several studies into green tea and its potential benefits, but there is, as yet, no conclusive evidence.RELATED ARTICLE
The results of this study do suggest that there is merit in further research into the effects of extracts of green tea, both in relation to its impact on the prevention of prostate cancer and in controlling progression in men already diagnosed with the disease, as was investigated in this instance."
These initial positive findings could indicate that green tea could have a place in 'active surveillance', where a slow-growing, low risk tumour is monitored for changes and men want to take something which could help keep progression at bay.
Potentially, this could mean completely avoiding, in some cases, any of the more usual medical interventions and their associated side effects."
Consumer Group Threatens Legal Action Against Bayer-HealthCare Over Vitamins' Anti- Prostate Cancer Claims
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A nonprofit consumer group, Center for Science in the Public Interest, said that it will sue Bayer HealthCare, alleging "deceptive and irresponsible" advertising that contends selenium in two of its multivitamins may reduce men's risk of prostate cancer.
The Center for Science in the Public Interest said it informed the multinational company of its intent Thursday.
David Schardt, the center's senior nutritionist, told reporters during a teleconference that the center already has filed a complaint with the Federal Trade Commission.
"It's astounding that a company such as Bayer ... would make such deceptive claims," the center's litigation director, Steve Gardner, told reporters during the same teleconference.
Supporting the center in its letter of complaint to the FTC are nine researchers, who wrote a separate letter to Mary Engle, associate director of advertising practices. Among the signees are medical professionals from:
- Harvard School of Public Health,
- American Cancer Society and
- University of Illinois at Chicago Division of Pathology Research.
A seven-year, $118 million study funded by the National Institutes of Health found last year that selenium does not prevent prostate cancer in healthy men, the center said.
The Selenium and Vitamin E Cancer Prevention Trial involving 35,000 U.S. and Canadian men was halted in October when researchers determined that selenium was not protecting the men from prostate cancer and may have been causing diabetes in some of them.
According to the researchers in their letter supporting the FTC's complaint,
"...the federally financed study was the largest individually, randomized cancer prevention trial ever conducted, and, given its high rates of adherence and its statistical power, it is unlikely to have missed detecting a benefit of even a very modest size.Bayer promotes One A Day Men's 50+ Advantage and One A Day Men's Health Formula multivitamins on package labels, TV and radio ads and on its Web site.
Bayer Healthcare is doing a disservice to men by misleading them about a protective role for selenium in prostate cancer."
Both dietary supplements contain 105 micrograms of the trace mineral selenium per daily dose, or about twice the Recommended Daily Allowance, which is 55 micrograms a day for adults, according to the center.
In its promotions, the company says "emerging research" suggests that selenium might reduce the risk of prostate cancer, the center said.
According to one radio ad:
"Did you know that there are more new cases of prostate cancer each year than any other cancer? Now there is something you can do."Trish McKernan, Bayer's global spokeswoman, told CNN:
"We are standing behind all the claims we make in support of the products. The selenium claims are made by a [Food and Drug Administration]-approved qualified health claim.Bayer's HealthCare division, based in Leverkusen, Germany, researches, manufactures and markets pharmaceutical products.
We regularly review the evidence, and we change our claims if necessitated. The emerging science hasn't compelled us to change our claims, and the FDA claim is intact."