The
milk thistle plant commonly grows from 2 to 7 feet in height, with
spiny leaves and reddish-purple, thistle-shaped flowers. It has
also been called wild artichoke, holy thistle and Mary thistle.
Native
to Europe, milk thistle has a long history of use as both a food
and a medicine. At the turn of the twentieth century, English gardeners
grew milk thistle to use its leaves like lettuce (after cutting
off the spines), the stalks like asparagus, the roasted seeds like
coffee, and the roots (soaked overnight) like oyster plant. The
seeds and leaves of milk thistle were used for medicinal purposes
as well, such as treating jaundice and increasing breast milk production.
German
researchers in the 1960s were sufficiently impressed with the history
and clinical effectiveness of milk thistle to begin examining it
for active constituents. In 1986, Germany's Commission E approved
an oral extract of milk thistle standardized to 70% crude silymarin
content as a treatment for liver disease.
What Is Milk Thistle Used for Today?
Based
on the extensive folk use of milk thistle in cases of jaundice,
European medical researchers began to investigate its medicinal
effects. It is now widely used to treat alcoholic hepatitis, alcoholic
fatty liver, liver cirrhosis, liver poisoning, and viral hepatitis,
as well as to protect the liver from the effects of liver-toxic
medications. According to some (but not all) research evidence,
treatment produces improvements in symptoms of chronic liver disease,
such as nausea, weakness, loss of appetite, fatigue, and pain.
Liver
enzymes as measured by blood tests may improve, and if a liver
biopsy is performed, there may be improvements on the cellular
level. In addition, some studies have shown a reduction in death
rate among those with serious liver disease.
The
active ingredients in milk thistle appear to be four substances
known collectively as silymarin, of which the most potent is named
silibinin. When injected intravenously, silibinin is one of the
few known antidotes to poisoning by the deathcap mushroom, Amanita
phalloides. Animal studies suggest that milk thistle extracts can
also protect against many other poisonous substances, from toluene
to the drug acetaminophen. One animal study suggests that milk
thistle can also protect against fetal damage caused by alcohol.
Silymarin
appears to function by displacing toxins trying to bind to the
liver as well as by causing the liver to regenerate more quickly.
It may also scavenge free radicals and stabilize liver cell membranes.
However, milk thistle is not effective in treating advanced liver
cirrhosis, and only the intravenous form can counter mushroom poisoning.
There is considerable evidence from studies in animals that milk
thistle can protect the liver from numerous toxins. However, human
studies of people suffering from various liver diseases have yielded
mixed results.