Milk Thistle, or Silybum marianum, is a weed-like plant that grows in rocky, dry soil. The plant reaches heights of 3 to 10 feet, has dark green, spiny leaves, and big flowers that range from pink to purple. A native to the Mediterranean, milk thistle now grows wild in Europe, North America, and Australia.
The Latin name marianum was derived from a legend that the herb’s leaf veins turned white after being touched by a drop of the Virgin Mary’s breast milk. The name milk thistle was given to the herb because of the milky white juice exuded by the leaves when crushed.
Milk Thistle’s healing properties were first recorded by Pliny the Elder, a Roman naturalist who completed the writing of Natural History in 77 A.D. Pliny claimed that milk thistle was good for “carrying off the bile”.
In the 16th century, the British herbalist John Gerard recommended milk thistle for “expelling melancholy”, which was something physicians of that time considered to be a liver ailment. Nicholas Culpeper, a 17th century herbalist, cited the herb’s use for opening “obstructions” of the liver and spleen.
By the 19th century, German doctors were using tincture made from milk thistle seeds for the treatment of many liver disorders. The German Commission E, the expert panel for the German government that judges the safety and effectiveness of medicinal herbs, fully approves milk thistle seeds or seed extracts as supportive treatment for disorders relating to the liver.
Milk thistle supplements are made from the seeds of the dried flowers. These seeds contain a bioflavonoid complex called silymarin, which is composed of silibinin, silidianin, and silicristin. The silibinin is considered the most active component.
The silymarin complex functions as an antihepatoxic, meaning it acts directly on the liver in order to protect it from toxins. The silymarin complex binds to the membranes of the liver cells, creating a tough shield so the toxins are less able to penetrate the cell walls. If toxins do get into the liver cells and cause damage, silymarin stimulates the liver to speed up production of beneficial enzymes and proteins that aid in healing.
One of the key methods in which milk thistle aids in the liver’s detoxification process is by preventing the depletion of glutathione (an amino acid). The higher the body’s glutathione content, the greater the liver’s capacity will be in detoxifying harmful chemicals. Normally, when we are exposed to damaging chemicals such as alcohol, drugs and pollution, the concentration of glutathione within the liver is substantially reduced. This reduction leaves the liver cells susceptible to damage. Studies have shown that silymarin not only prevents the typical depletion of glutathione but actually increases the level of glutathione in the liver by up to 35 percent.
The National Center for Complimentary and Alternative Medicine (NCCAM) has funded a study designed to better understand the use of milk thistle for chronic hepatitis C and nonalcoholic steatohepatitis (liver disease).
According to Memorial Sloan-Kettering Cancer Center, placebo-controlled clinical studies show milk thistle’s efficacy in reducing aminotransferases in alcoholic disease. Conclusions from a systematic review also suggest milk thistle’s usefulness in the treatment of liver cirrhosis.
Milk thistle is generally well tolerated with few side effects. In rare instances, milk thistle can cause a laxative effect, upset stomach, diarrhea, or bloating.
As with all treatments, both conventional and alternative, be sure to check with your doctor for any possible drug interactions or cautions pertaining to your own situation.