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Four Glasses of Red Wine in Week Cut Prostate Cancer
Rate 50 Percent
Sept. 22, 2004 – Drinking a glass of red wine a day
may cut a man's risk of prostate cancer in half, and the protective
effect appears to be strongest against the most aggressive forms of the
disease, according to a new study led by investigators at Fred
Hutchinson Cancer Research Center.
The findings, by Janet L. Stanford, Ph.D., and
colleagues in Fred Hutchinson's Public Health Sciences Division, appear
online in The International Journal of Cancer.
"We found that men who consumed four or more
glasses of red wine per week reduced their risk of prostate cancer by 50
percent," Stanford said. "Among men who consumed four or more 4-ounce
glasses of red wine per week, we saw about a 60 percent lower incidence
of the more aggressive types of prostate cancer," said Stanford, senior
author of the study. "The more clinically aggressive prostate cancer is
where the strongest reduction in risk was observed."
Stanford and colleagues found no significant
effects – positive nor negative – associated with the consumption of
beer or hard liquor and no consistent risk reduction with white wine,
which suggests that there must be a beneficial compound in red wine that
other types of alcohol lack. That compound, Stanford and colleagues
believe, may be an antioxidant called resveratrol, which is abundant in
the skins of red grapes but much less so in the skins of white grapes.
The compound is also found in peanuts and raspberries and is available
as a dietary supplement, which has been suggested to protect against
cardiovascular disease.
Laboratory studies indicate that resveratrol
influences a variety of biological pathways that are important in cancer
development. For example:
>> As an antioxidant, it helps sweep dangerous,
cancer-causing free radicals from the body.
>> As a potent anti-inflammatory agent, it blocks
certain enzymes that promote tumor development.
>> The compound also reduces cell proliferation,
curtailing the number of cell divisions that could lead to cancer or the
continued growth of cancer cells.
>> It also enhances apoptosis, or programmed cell
death, which helps rid the body of cancerous cells.
>> It may act as an estrogen, reducing levels of
circulating male hormones such as testosterone that fuel the growth of
prostate cancer.
While the researchers found that the risk of
prostate cancer decreased 6 percent for every glass of red wine consumed
per week, Stanford is quick to point out that research shows the law of
diminishing returns comes into play when consumption increases beyond
moderation. "From a public-health standpoint, it's difficult to
recommend any alcohol consumption given the risks associated with heavy
consumption, from increased overall cancer risk to accidental injury and
social problems. But for men who already are consuming alcohol, I think
the results of this study suggest that modest consumption of red wine –
four to eight 4-ounce drinks per week – is the level at which you might
receive benefit. Clearly other studies show that more than that may have
adverse effects on health."
For the study, the researchers interviewed 753
newly diagnosed Seattle-area prostate-cancer patients as well as 703
healthy controls who served as a comparison group. Detailed information
about tumor aggressiveness (such as tumor grade and disease stage) was
obtained through the National Cancer Institute's Seattle-Puget Sound
Surveillance, Epidemiology and End Results cancer registry.
"Even though this study is based on relatively
small numbers, the results are very intriguing and suggest that the
potential beneficial effect of red wine and resveratrol – if indeed
resveratrol is the active chemopreventive agent involved – would be very
important, because it's the more aggressive forms of prostate cancer
than are most important to prevent," she said.
A particular strength of the study, Stanford said,
is that the participants were relatively young, ranging in age from 40
to 64, and the majority were under 60.
"By focusing on men under age 65, whose incidence
of prostate cancer is much lower than that of older men, we can tease
out the effect of a particular environmental exposure on cancer risk,
such as wine consumption, more easily than if we were looking at men
across the entire age range," she said. This is particularly true when
studying complex diseases such as prostate cancer in which numerous
genetic and environmental factors are thought to play a role over an
individual's lifetime.
Another strength of the study is that in addition
to being surveyed about lifetime alcohol consumption, participants were
asked about a variety of other risk factors for prostate cancer, such as
diet, family history of cancer, screening for prostate cancer and
tobacco use, all of which were taken into account and adjusted for when
analyzing the data.
While the majority of studies to date have assessed
the effects of overall alcohol use on prostate-cancer risk, fewer
studies have attempted to compare the effects of wine versus beer versus
hard liquor, and only one previous study has compared the impact of red
versus white wine on prostate-cancer risk, said Stanford, also a
professor of epidemiology at the University of Washington School of
Public Health and Community Medicine.
The previous study, the Netherlands Cohort Study,
evaluated prostate-cancer risk in relation to white and red wine
consumption. Increased risks were found in men who consumed "white and
fortified wines," but not red wine, as compared to nondrinkers, although
there was not a consistent trend in risks with levels of intake.
Interestingly, among men who consumed 15 or more grams of red wine per
day (about one and a half glasses per day), there was an overall 18
percent reduction in risk and a 16 percent lower risk of advanced-stage
prostate cancers. The Netherlands Cohort Study was initiated in 1986 and
collected information by self-administered mailed questionnaires that
asked about alcohol consumption during the prior year only. Thus, the
Netherlands Cohort Study results only reflect associations with recent
wine consumption, as investigators were unable to examine lifetime
intake as was done in the current Fred Hutchinson study.
"One of the reasons we wanted to do this study is
because overall, most of the scientific literature – around 17 studies
to date – haven't shown a consistent relationship between alcohol
consumption and prostate cancer," Stanford said. "Some have shown an
increase, some a decrease, and most no association whatsoever. Part of
the problem, we believe, is that few of the studies have attempted to
sort out the effects of different types of alcohol intake over a man's
lifetime."
Stanford and colleagues plan to seek funding to
conduct a larger study to see if their results hold up. In collaboration
with Norm Greenberg, Ph.D., of Fred Hutchinson's Clinical Research
Division, they also plan to test the effects of resveratrol on mouse
models of prostate cancer to see if giving mice this chemical compound
will reduce the onset of prostate cancer and/or decrease the
aggressiveness of the disease.
The first author of the study, W. Marieke Schoonen,
M.S., formerly a graduate student in Stanford's group, is now a doctoral
student at the London School of Hygiene and Tropical Medicine. The
National Cancer Institute, National Institutes of Health and U.S.
Department of Health and Human Services funded the research.
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