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Potential Health Benefits of Milk Thistle

Milk thistle (Silybum marianum L.) is an ancient medicinal plant from the Mediterranean region. It was named after its white-veined leaves that were thought to resemble the Virgin Mary’s milk. Other common names of this herb include blessed milkthistle, holy thistle, Lady’s thistle, Mary thistle and Marian thistle. In the past, milk thistle was mainly used to treat the liver. Since most types of liver damage prove difficult to treat with conventional drugs, this herb is in certain cases worth a try. It has even been used for liver damage due to mushroom poisoning.

Although milk thistle has not been proven beyond doubt to be effective for any of the conditions it is used for, it is highly unlikely to do any harm. At the very least, most researchers agree that it is an effective treatment for liver damage caused by long-term alcohol abuse. Milk thistle is generally safe although some people should avoid taking it including pregnant and breastfeeding women and small children.

Health Effects of Milk Thistle

Like all medicinal plants, milk thistle contains more than just one active ingredient. Its most important ingredient is the flavonoid silymarin which is made up of a group of compounds including silybin A and B, silydiamin and silydristin. These substances cause changes in the membrane of liver cells that make it harder for foreign substances to enter the cells, thereby protecting the liver from toxins. Moreover, silymarin possesses anti-viral, anti-inflammatory and anti-oxidative properties. It also appears likely that milk thistle improves the liver’s ability to regenerate itself once it has been damaged.

Mostly because of the high flavonoid content, milk thistle is thought to protect the liver against toxins. Therefore, it has been used for centuries to treat liver diseases and to detoxify the liver. Its other beneficial effects on the body include promoting the production of enzymes and bile, and thus improving digestion.

Most importantly, milk thistle is used as an alternative treatment for patients with hepatitis (due to toxic liver damage or viral infection) and liver cirrhosis (due to alcohol abuse or long-term hepatitis). It has also been used as an antidote for mushroom poisoning. In addition, milk thistle can offer protection to the liver from damage caused by chemotherapy, radiation, iron overload and psychotropic medications.

Other health benefits of milk thistle include preventing gallstones, kidney damage caused by toxins as well as skin damage, lowering blood sugar levels and cholesterol, promoting immune system function and fertility, helping with osteoarthritis, and improving the symptoms of allergy and psoriasis. The latest research suggests that milk thistle could be also beneficial in the treatment of Parkinson’s and Alzheimer’s diseases and multiple sclerosis. This effect is linked to its neuroprotective properties.

Potential Health Risks of Milk Thistle

On the whole milk thistle is safe. Occasionally it can cause diarrhea, which disappears once the treatment with the herb is discontinued. Nonetheless, milk thistle is not recommended for pregnant and breastfeeding women because it is not known for certain whether it does not harm the baby. For the same reason, milk thistle should not be given to children. In addition, because of its estrogen-stimulating properties, the herb should not be used by patients diagnosed with estrogen-sensitive cancers such as breast cancer.

Since milk thistle improves liver functions including the liver’s ability to process foreign substances such as drugs, it is possible that it may cause undesired drug interactions. It could lower the blood levels of drugs that are processed in the liver, thus lessening their effect. Therefore, patients should let their doctor know that they are taking or plan to take this herb.

Recommended Dosages of Milk Thistle

Milk thistle comes as pills, powder and liquid (tinctures) made from the plant’s leaves, seeds and sometimes also fruit. Quality products are usually standardised to a silymarin content of 70%. The recommended daily dosage and the length of treatment depend on the condition treated. For many conditions, up to 800mg of standardized silymarin a day are recommended in two to three divided doses for up to 12 months. However, unless specified by the doctor, milk whistle should not be taken for longer than three months at a time.

Where to Get More Information: University of Maryland Medical Center