A popular herbal
pill used by millions of men may not reduce the
frequent urge to go to the bathroom or other annoying
symptoms of an enlarged prostate, a rigorous new study
concludes. The findings were published in
Thursday's New England Journal of Medicine.
The yearlong
research found that the plant extract, saw palmetto,
was no more effective than dummy capsules in easing symptoms
for the 225 men in the study. The results contrast
with previous research that showed saw palmetto to be
effective.
"This
certainly sheds some doubt on whether the product's
effective and suggests that it might not work,"
said the lead researcher, Stephen Bent, of the San
Francisco VA Medical Center.
More than 2
million American men take the herb to treat an enlarged
prostate, and it is widely used in Europe, the researchers
said. Until their results are confirmed by more
studies, men who take saw palmetto and feel it works
should probably keep using it, Bent said.
The prostate is a
walnut-sized gland that surrounds the urethra, the tube
that carries urine from the bladder. Benign enlargement is a
common condition as men age, and it causes problems
with urination. This condition has nothing to do with
prostate cancer.
The saw palmetto
is a small palm native to the southeastern United
States. The extract comes from its olive-size berries and is
sold over the counter in capsule form. It is the
third-highest-selling herbal dietary supplement in the
U.S., after garlic and echinacea, according to the
American Botanical Council. Unlike prescription drugs,
dietary supplements do not need government approval.
Bent said he and
his colleagues picked saw palmetto to study because of
its widespread use and positive findings from previous
studies, which were smaller and shorter than his
federally funded research. Some of his colleagues have
received fees or support from drugmakers.
The new study
recruited men over 49 with enlarged prostates who had
moderate to severe symptoms. They took 160 milligrams of saw
palmetto twice a day or similar-looking dummy
capsules. At each visit, they filled out a symptoms
survey, and their urine flow was measured. After a year
there was no significant difference between the groups in
symptom changes or other measures, the researchers
reported.
Bent said the
dummy capsule was carefully designed to match the brown
color, bitter taste, and strong odor of the extract. At the
end of the study, 40% in the saw palmetto group and
46% in the comparison group thought they were getting
the extract, which shows how well the capsules were
disguised.
"It's a theory of ours, but we think that
might be one of the reasons that our study
didn't work, whereas prior studies did work,"
Bent said, suggesting that men in other studies may
have figured out they were getting a placebo.
Mark Blumenthal,
head of the American Botanical Council, which follows
research on herbs, said saw palmetto is recommended for
milder symptoms than those included in the latest
research.
"I
don't [fault them for] raising the bar. I do think
it's unfortunate they didn't raise the
dosage," said Blumenthal, who has been taking the
extract for about a decade.
Bent said they
recruited the same kind of patients used to test
prescription drugs for enlarged prostate, and the dosage was
identical to that used in earlier tests of saw
palmetto.
"Now that
this study is negative, I think it's reasonable to
try a higher dose," said Bent.
A larger study of
herbal remedies, including saw palmetto, is in the
final planning stages.
In a journal
editorial, physicians Robert S. DiPaola and Ronald A. Morton
at the University of Medicine and Dentistry of New Jersey,
note that only one formula of saw palmetto was tested
and suggest that other preparations or doses might
work.
"What I
tell men is that they may not do themselves any harm by
taking it. It's just that I'm not
certain they're going to do themselves any good
taking it," said Morton. (AP)