Milk Thistle
Background
Milk
thistle is native to southern Europe, southern Russia, Asia Minor, and
northern Africa. It also grows in North and South America and
South Australia.
Silymarin is considered to be the main
component of milk thistle seeds, but the terms “milk thistle” and
“silymarin” often are used interchangeably.
Historically, people have used milk thistle for liver disorders, such
as hepatitis and cirrhosis, and gallbladder problems.
Silymarin is the most commonly used
herbal
supplement in
the United States for liver problems.
Milk thistle products are available as capsules, powders,
and extracts.
How Much Do We Know?
We
know little about whether milk thistle is effective in people, as only
a few well-designed clinical studies have been conducted.
What Have We Learned?
Results
from clinical trials of milk thistle for liver diseases have been
mixed, and two rigorously designed studies found no benefit.
The
2008 Hepatitis C Antiviral Long-Term Treatment Against Cirrhosis
(HALT-C) study, sponsored by the National Institutes of Health (NIH),
found that hepatitis C patients who used silymarin had fewer and milder
symptoms of liver disease and somewhat better quality of life but no
change in virus activity or liver inflammation.
A 2012
clinical
trial,
cofunded by the National Center for Complementary and Integrative
Health (NCCIH) and the National Institute of Diabetes and Digestive and
Kidney Diseases, showed that two higher-than-usual doses of silymarin
were no better than placebo for chronic hepatitis C in people who had
not responded to standard antiviral treatment.
Results from a
2013 clinical study suggest that milk thistle may enhance standard
treatment in young people with a particular form of anemia
(Cooley’s anemia).
What Do We Know About Safety?
In
clinical trials, milk thistle appears to be well tolerated in
recommended doses. Occasionally, people report various gastrointestinal
side effects.
Milk thistle may produce allergic reactions,
which tend to be more common among people who are allergic to plants in
the same family (for example, ragweed, chrysanthemum, marigold,
and daisy).
Compounds in milk thistle may lower blood sugar
levels in people with type 2 diabetes. People with diabetes should
use caution.
Keep in Mind
Tell all your health care
providers about any complementary or integrative health approaches you
use. Give them a full picture of what you do to manage your health.
This will help ensure coordinated and safe care.
Key References
- Abenavoli
L, Capasso R, Milic N, et al. Milk
thistle in liver diseases: past, present, future. Phytotherapy Research. 2010;24(10):1423-1432.
- Fried
MW, Navarro VJ, Afdhal N, et al. Effect
of silymarin (milk thistle) on liver disease in patients with chronic
hepatitis C unsuccessfully treated with interferon therapy: a
randomized, controlled trial. JAMA. 2012;308(3):274-282.
- Loguercio
C, Festi D. Silybin
and the liver: from basic research to clinical practice. World Journal of
Gastroenterology. 2011;17(18):2288-2301.
- Milk
Thistle. Natural Medicines Web site. Accessed at
naturalmedicines.therapeuticresearch.com on April 8, 2015.
[Database subscription].
- Moayedi
B, Gharagozloo M, Esmaeil N, et al. A
randomized double-blind, placebo-controlled study of therapeutic
effects of silymarin in B-thalassemia major patients receiving
desferrioxamine. European Journal of Haematology. 2013;90(3):202-209.
- Polyak
SJ, Oberlies NH, Pecheur E-I, et al. Silymarin
for HCV infection. Antiviral Therapy. 2013;18(2):141-147.
- Seeff
LB, Curto TM, Szabo G, et al. Herbal
product use by persons enrolled in the Hepatitis C Antiviral Long-Term
Treatment Against Cirrhosis (HALT-C) trial. Hepatology. 2008;47(2):605-612.
-NIH
