Milk Thistle (Silymarin) is an herbaceous annual or biennial plant with a dense prickly flower head that has purplish tubular flowers. It is an edible plant native to southern Europe, southern Russia, Asia Minor, and northern Africa, and has been used for food in the countries surrounding the Mediterranean for a long time as well as a tonic herb for the liver. Virtually all parts of the plant have been used as food with no known toxicity. Silymarin was introduced to North America by European colonists.
Today, Milk Thistle is best known as a producer of a liver protectant known as silymarin, a group of Milk Thistle flavonoids. Milk Thistle used in commerce is a standardized extracts prepared from the fruits (seeds) of Silybum marianum. Like Ginkgo Biloba, Milk Thistle is required to be standardized and rendered to concentrated forms to be effectively used for desired medicinal purposes, which, in this case, is as a hepatoprotectant. In general, Milk Thistle extracts are standardized to a concentration of 70-80% of flavone lignans including isosilybinin, silybinin, silychristin, and silydianin, which are collectively called silymarin.
The main reason for the popularity of Silymarin is that it both protects the Liver, and improves its function. It protects the liver by altering and strengthening the structure of outer cell membranes of hepatocytes (liver cells), preventing toxins from entering the liver cells, and by stimulating the regenerative ability of the liver and the formation of new hepatocytes through the activation of an enzyme nucleolar polymerase A, which leads to the increase in ribosomal protein synthesis and cell division.
Silymarin regenerates the liver at the cellular level
Silymarin, as an anti-oxidant, may also reduce damages to liver cells caused by chronic use of certain prescription drugs. The silybin component of sillymarin has been related to cholesterol-lowering effects. Through the capability to increase bile solubility, sylimarin may also help prevent or alleviate gallstones.
In addition, there are no contra-indications that I know of for Milk Thistle. I can find no reports of bad reactions; the only mild reaction which has been noted is occasional loosening of the bowels. This is nearly always for a few days only; and is because Milk Thistle stimulates Liver function. Extra bile is therefore produced, which may have a temporary laxative effect.
No side effects are known for crude preparation, as Silymarin is a food, and a relative of artichoke. For standardized extract with high concentration of sylimarine, a mild laxative effect has been observed occasionally.
The only noteworthy interactions with drugs have been where Silymarin has reduced the damaging effects of taking drugs. Milk Thistle is widely regarded in the natural therapy field as being protective of the Liver when drugs are being taken.
The most active parts of Milk Thistle appear to be a group of agents known collectively as ‘Silymarin’. Certainly, research has shown that Silymarin appears to have two particular effects on the Liver:
1. Silymarin protects the Liver from damage due to toxins or disease, and
2. Silymarin can actually boost regeneration of Liver tissue at the cellular level where there has been damage.
This explains why Milk Thistle has been popular to take alongside medical drugs. For example, some sources recommend taking this herb where chemotherapy is being used. Also, Milk Thistle appears to promote repair of damaged Liver tissue following alcohol abuse. Milk Thistle is also recommended to assist recovery after hepatitis, which can cause damage to the Liver. A further use of Milk Thistle is for nursing mothers to improve breast milk.
Milk Thistle has been shown in laboratory experiments to protect the Liver against attack by carbon tetrachloride — a strong poison found in some household cleaners; and against Death Cap mushroom — which can be fatal if eaten. Such results highlight its protective abilities.
Milk Thistle is certainly a safe and valuable herb to protect and repair the Liver. The Liver is abused so much in everyday living — stress, pollution, and chemicals are all a challenge for the Liver; anything that we can do to improve the Liver’s ability to cope with these influences will be for the good.