General Description
Milk thistle is an annual/biennial plant that grows in dry, rocky
soil throughout southern and western Europe, and in some parts of
the United States. The branched stem grows up to three feet in height
and bears spiny, scalloped-edged leaves, which are dark green in
color and streaked with white along the veins. Milk thistle flowers
from June to August, bearing a single spiny, reddish-purple blossom.
The fruit of the plant (commonly misidentified as the seed) is used
for health purposes.
Health applications
- Liver health
- Detoxification
- Hepatitis
- Cirrhosis
- Diabetes
History and traditional use
For more than 2,000 years, milk thistle has been used as a medicinal
herb for a wide range of applications. In the Middle Ages, it was
used to treat liver diseases, and as a general tonic for the stomach,
gall bladder, and spleen. The renowned eighteenth-century herbalist
Culpepper recommended it for treatment of jaundice and "obstructions"
of the liver and spleen. Milk thistle was also used in folk medicine
to promote milk production in nursing mothers (a practice from which
the herb's common name originates). Milk thistle remains popular
to this day as a natural tonic for rejuvenating the liver.
Chemical composition
The active components of milk thistle are a group flavonoids known
as silymarin, which consists of three compounds: silibinin, silydianin,
and silychristin. Of the three, silibinin appears to exhibit the
most biological activity. Milk thistle extracts are commonly standardized
to contain 70 to 80 percent silymarin.
Liver health
Most of the health applications of milk thistle relate to its
impact on the liver. Standardized milk thistle extracts are approved
by the German Commission E (Germany's counterpart to the FDA)
for the treatment of toxic liver damage and for supportive treatment
of chronic inflammatory liver disease and chronic hepatic cirrhosis.
According to The Complete German Commission E Monographs, the
therapeutic activity of silymarin is based on two mechanisms of
action: (a) it alters the structure of the outer membrane of liver
cells in such a way as to prevent penetration of toxins into the
interior of the cell; (b) it stimulates an increase in protein
synthesis, contributing to the formation of new liver cells and
the regenerative capability of the liver.1
Research shows that silymarin has powerful antioxidant properties
that enhance the activity of the primary liver antioxidants superoxide
dismutase (SOD)2,3 and glutathione peroxidase.4
Studies indicate that silymarin can help improve liver function
in people with cirrhosis,2-11 diabetes,12,13
and viral hepatitis.14,15
Detoxification
Milk thistle's popular use as a detoxifier and general system
cleanser appears consistent with the herb's activity as a liver
tonic. The liver is responsible for removing many toxic substances
from the body, and milk thistle's ability to enhance the antioxidant
activity of liver enzymes may aid this process. Studies have shown
that silymarin counteracts the toxic effects of Deathcap mushroom
(Aminita phalloides),16-19 acetaminophen,20
and a variety of other poisons.
Dosage/Toxicity
Studies on milk thistle have used doses ranging from 200 to 600
mg per day, and there have been no significant side effects reported
in this dosage range. Milk thistle has no known toxicity, even
in extremely high doses. To ensure consistent potency, most herbalists
recommend milk thistle extracts that are standardized to contain
70 to 80 percent silymarin. |
