Milk thistle (Silybum marianum) — also known as St Mary’s thistle, holy thistle and, more recently, silymarin — like most thistles, has prickly leaves and reddish, purple flowers on a spiky flower bud. Its name refers to the white blotches along the veins of the leaves. The part used medicinally is the ripe seeds, which are grey/black and shiny.
It was once grown extensively in Europe as a vegetable, with the de-spined leaves eaten as a salad green and the flower eaten in a similar way to artichokes, but the plant has long since turned wild. Although native to the Mediterranean region, milk thistle can now be found growing on dumping grounds, in unused paddocks, on stony slopes or in any other infertile patches of ground throughout the world, including the USA and Australia, where it has been classified as an invasive species in some states.
The medicinal use of milk thistle dates back at least 2000 years, being noted in both ancient Greek and Roman texts. England’s most famous 17th century herbalist, Nicholas Culpepper (1616–1654), used milk thistle to treat obstructions of the liver and spleen and as a remedy for jaundice.
Milk thistle chemistry
The antioxidant flavonolignans found in milk thistle are thought to be responsible for the herb’s medicinal properties. Collectively known as silymarin, this compound is actually a complex mix of several flavonolignans, including silybin and silychristin.
A powerful antioxidant, silymarin has the ability to protect liver cells from damage by harmful chemicals and toxins, including environmental pollutants and synthetic drugs as well as naturally occurring poisons such as those found in the death cap mushroom. Silymarin is the most important treatment used in death cap mushroom poisoning, significantly reducing the mortality rate from it. Silymarin causes changes in the structure of the outer layer of liver cells, which prevents the penetration by toxins into the internal parts of liver cells.
Silymarin has also been shown to increase the levels of glutathione inside liver cells by as much as 35 per cent. Glutathione is an antioxidant produced by the body to protect cells from free radical damage. Another way silymarin improves liver health is by stimulating protein synthesis in liver cells, leading to regeneration of the liver and the formation of entirely new liver cells. Silymarin is one of the only known substances to stimulate the regeneration of new liver cells.
Medicinal uses
Hepatitis
Hepatitis is an inflammation of the liver most commonly caused by alcohol abuse or infection with the hepatitis virus types B and C. Both alcohol-related and viral hepatitis can lead to chronic liver disease and eventually progress to liver failure and death.
While milk thistle seems to have very little effect on the number of virus particles found in the body of a person with the hepatitis virus, it does protect the liver from damage caused by the virus and the actions of the immune system. The low incidence of side-effects in those treated with milk thistle makes it an ideal complementary medicine to conventional hepatitis treatments. A 2005 review of clinical trials using milk thistle noted that, in all the trials reviewed, death from liver-related causes was significantly reduced in those treated with milk thistle.
Liver protection
The levels of several liver enzymes in the blood are routinely used to monitor the progress of existing liver inflammation and also to screen for liver diseases. Elevated liver enzymes can have many causes, including glandular fever, a night of heavy drinking and also carrying too much abdominal fat. Milk thistle has the ability to protect the liver from damage and reduce elevated liver enzymes.
Milk thistle is frequently used by those undergoing treatment for cancer to help prevent some of the liver-damaging effects of chemotherapy drugs. While the simultaneous use of milk thistle and chemotherapy is not advised, there has been some research into the use of milk thistle before chemotherapy. A 2005 study found that when milk thistle was used for two weeks up until four and 12 days before chemotherapy, no changes in drug metabolism were seen at either time point.
Gallbladder problems and IBS
The gallbladder is involved in the excretion of bile in the gut for the digestion of dietary fat. Gallstones and gallbladder problems can cause pain, nausea and intolerance of fatty foods due to a decrease in bile flow and cramping of the gallbladder duct. Milk thistle has a gentle bile-stimulating action that can aid with the management of gallstones and may also help reduce the cramping, painful symptoms of gallbladder attacks. There is some research showing that milk thistle may also help with the cramping pain associated with irritable bowel syndrome (IBS).
Cancer prevention
The potent antioxidant activity of milk thistle has provoked interest from cancer researchers who are beginning to examine the use of silymarin in cancer prevention and treatment. Early laboratory results have recently shown a protective effect of milk thistle against breast, prostate and skin cancer.
Using milk thistle
The recommended dose of milk thistle is 3000–6000mg of dry herb equivalents taken each day and it’s best taken before food. There is potential for reactions to occur between milk thistle supplements and other medications, so check with your Health professional before using milk thistle if you are taking any medications.
