Release Date: May 2, 2005
MILK THISTLE
DOES NOT REDUCE DEATHS FROM LIVER DISEASES, BEST STUDIES FIND
By Lise Stevens, Contributing Writer
Health Behavior News Service
Milk thistle, a widely used alternative medicine, is not proven effective
in lowering mortality in alcoholic or hepatitis B or C liver disease,
according to a systematic review of current evidence.
While some studies found that liver-related mortality may be significantly
reduced in patients treated with milk thistle, these findings were
not duplicated in the higher quality clinical trials.
However, milk
thistle was found safe to us with no serious side effects and with
participants perceiving improvement
in symptoms — although
no more than with placebo.
Dr. Andrea Rambaldi, visiting researcher at the of the Centre for
Clinical Intervention Research at Copenhagen University Hospital, led
a team that reviewed 13 randomized clinical trials involving 915 patients
who were treated with milk thistle or its extracts.
Participants had acute or chronic alcoholic liver cirrhosis, liver
fibrosis, hepatitis and/or steatosis, and viral-induced liver disease
(hepatitis B and/or hepatitis C). Patients with rarer specific forms
of liver disease were excluded.
All the trials
compared the efficacy of milk thistle or any milk thistle constituent
versus placebo or no intervention
in patients with liver
disease. “There is no evidence supporting or refuting milk thistle
for alcoholic and/or hepatitis B or C virus liver diseases,” the
authors found.
The review appears in the most recent issue of The Cochrane Library,
a publication of The Cochrane Collaboration, an international organization
that evaluates medical research. Systematic reviews draw evidence-based
conclusions about medical practice after considering both the content
and quality of existing medical trials on a topic.
According to the Centers for Disease Control and Prevention, 170 million
people worldwide are infected with hepatitis C, and 2 billion are infected
with hepatitis B.
While a vaccine exists to prevent hepatitis B, there is no vaccine
for hepatitis C.
Although the virus can be cleared in a handful of patients, many strains
are resistant to treatment. Drug therapies that focus on long-term
suppression of the virus are expensive, and many patients develop a
resistance. The current gold standard treatment, which combines injections
of interferon and ribavirin, has serious side effects and is hard for
patients to tolerate.
With lack of effective treatment for liver disease, researchers have
been looking for alternative therapies that curb symptoms with minimum
adverse effects on patients.
Milk thistle and its extracts have been used since the time of ancient
Greece for medicinal purposes, are currently widely used in Europe
for liver disease, and are readily available in the United States at
alternative medicine outlets and outdoor markets.
G. Thomas Strickland, M.D., Ph.D., professor at the University of
Maryland School of Medicine, has been studying the role of silymarin,
an extract of milk thistle, in preventing complications of chronic
hepatitis virus infection. Strickland says that the exact mechanism
of action of silymarin is unclear.
A problem with
current trials, according to Dr. Strickland, is that the dose of
silymarin administered, typically 140 mg three
times daily,
is too low. “I would certainly double it,” he says, “especially
since at the current dose we’re not seeing any improvement in
acute viral or chronic hepatitis, and we’ve shown that silymarin
is totally safe.”
“ The problem is, there is no cure for viral hepatitis except
bed rest and diet, and treatments like silymarin are worth pursuing,” Strickland
says, calling for more research funding.
“ We should consider doing randomized clinical trials with
higher doses of silymarin,” Dr. Rambaldi concurs.
According to the National Center for Complementary and Alternative
Medicine , a part of the National Institutes of Health, studies in
laboratory animals suggest that silymarin may benefit the liver by
promoting the growth of certain types of liver cells, demonstrating
a protective effect, fighting oxidation (a chemical process that damages
cells) and inhibiting inflammation.
In their review,
Dr. Rambaldi and colleagues conclude, “Milk
thistle could potentially affect alcoholic and/or hepatitis B or C
virus liver diseases. Therefore, large-scale randomized clinical trials
on milk thistle for alcoholic and/or hepatitis B or C liver diseases
versus placebo may be needed.” Rambaldi A, Jacobs
BP, Iaquinto G, Gluud C. Milk thistle for alcoholic and/or hepatitis
B or C virus liver diseases. The Cochrane Database of Systematic
Reviews 2005, Issue 2.
The Cochrane Collaboration is an international nonprofit, independent
organization that produces and disseminates systematic reviews of
health care interventions and promotes the search for evidence in
the form of clinical trials and other studies of interventions. Visit
http://www.cochrane.org for more information.
FOR MORE INFORMATION:
Health Behavior News Service: (202) 387-2829 or www.hbns.org.
Center for the Advancement of Health
Contact: Ira R. Allen
Vice President of Public Affairs
202.387.2829
press@cfah.org
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