Study finds a diet high in vegetables and lean protein, and low in fat and
red meat, combined with moderate alcohol use reduces the risk of
symptomatic benign enlargement of the prostate
SEATTLE, Feb. 12 /PRNewswire-FirstCall/ -- Men who eat a diet low in
fat and red meat but high in vegetables and lean protein and who drink
alcohol in moderation may not just be doing their hearts a favor. A new
study shows that such a heart-healthy diet may also be good for the
prostate.
Specifically, such a diet significantly decreases the risk of
symptomatic benign prostatic hyperplasia, or BPH. The bothersome condition
is associated with frequent and painful urination that affects about half
of all men by the time they reach 50 and nearly all men by age 70. These
findings by lead author Alan Kristal, Dr.P.H., and colleagues are published
online in the American Journal of Epidemiology.
The researchers found that a high-fat diet increased the risk of benign
enlargement of the prostate by 31 percent, and that daily consumption of
red meat increased the risk by 38 percent. The study also found that eating
four or more servings of vegetables daily was associated with a 32 percent
reduction in risk, consuming high amounts of lean protein (about 20 percent
of daily calorie intake) was associated with a 15 percent risk reduction,
and that regular, moderate alcohol consumption (no more than two drinks a
day) was associated with a 38 percent decline in BPH risk.
"It is known that obesity increases the risk of BPH. The dietary
pattern that is associated with obesity among men in the United States is
high fat consumption. The results of this study clearly show a link between
a high-fat diet and increased risk of BPH," said Kristal, member and
associate head of the Cancer Prevention Program in the Public Health
Sciences Division at the Hutchinson Center.
Prostate enlargement puts pressure on the urethra, which makes it
difficult to empty the bladder completely, which in turn results in the
frequent urge to urinate. BPH is also associated with constant contraction
of the prostate gland's smooth-muscle tissue, which also puts pressure on
the urethra.
The mechanisms behind excess fat intake and increased risk of BPH are
not clearly established, but likely factors include chronic inflammation
and changes in steroid hormones.
"We don't really know how it's working but it's pretty clear that
eating a high amount of fat -- and it doesn't appear to matter what kind of
fat -- increases the risk of BPH," Kristal said.
The study found small, incremental increases in BPH risk as fat intake
increased, with the most substantial risk -- more than 30 percent -- among
men who got about 40 percent of their calories from fat.
High fat intake increases the body's overall inflammatory response and
it also increases levels of circulating hormones such as estrogens and
androgens, he said, both of which may affect prostate tissue. In contrast,
a low fat, high vegetable and moderate alcohol consumption pattern is
associated with less obesity, lower circulating estrogens and androgens and
less stimulation of the sympathetic nervous system.
"It is possible that these physiological effects moderate both the
hormonally regulated prostate growth and heightened smooth-muscle tone that
cause BPH," the authors wrote.
The mechanism by which moderate alcohol consumption appears to protect
against BPH may be due to its effects on the production and metabolism of
testosterone, Kristal said. Moderate alcohol use lowers circulating
hormones and decreases muscle tone of the prostate.
Few studies to date have examined dietary patterns and BPH risk, and
most have been small and have collected very limited data.
For the current study, Kristal and colleagues assessed diet, supplement
use and alcohol consumption in 4,770 men for seven years, 876 of whom
developed symptomatic BPH. They collected the data in the context of a
larger randomized clinical trial that aimed to determine whether
finasteride, a drug used to treat BPH, would also prevent prostate cancer.
The men involved in this analysis, all 55 and older, participated in the
placebo arm of the finasteride trial. All were free of BPH symptoms at the
start of the study and received annual screening for signs of prostate
enlargement.
"Being able to study men in the placebo arm who weren't taking
finasteride allowed us to look at factors other than finasteride to predict
BPH risk," Kristal said.
The study found no evidence that specific supplements, such as
antioxidants, zinc or calcium, were associated with reduced risk.
Co-authors on the paper included researchers from the Hutchinson
Center, the Keck School of Medicine at the University of Southern
California and the University of Texas Health Sciences Center at San
Antonio. The National Institutes of Health funded this research.
At Fred Hutchinson Cancer Research Center, our interdisciplinary teams
of world-renowned scientists and humanitarians work together to prevent,
diagnose and treat cancer, HIV/AIDS and other diseases. Our researchers,
including three Nobel laureates, bring a relentless pursuit and passion for
health, knowledge and hope to their work and to the world. For more
information, please visit http://www.fhcrc.org.
CONTACT
Kristen Woodward
(206) 667-5095
kwoodwar@fhcrc.org
SOURCE Fred Hutchinson Cancer Research Center
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Related links:
http://www.fhcrc.org/
CONTACT:
Kristen Woodward of Fred Hutchinson Cancer
Research Center, +1-206-667-5095, kwoodwar@fhcrc.org
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