Milk ThistleSilybum marianum
• Silymarin, Silibinin
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 as a treatment for liver disease. However, the evidence that it really works remains incomplete and inconsistent.
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 currently used to treat alcoholic hepatitis
Standardized milk thistle extract is known as silymarin. Silymarin itself is a mixture of at least seven chemicals. The most active of these chemicals is commonly known as silibinin. But, silibinin too is, in fact, a mixture, comprising the two related substances silibinin A and silibinin B.
Silibinin is hypothesized to function by displacing toxins trying to bind to the liver as well as by causing the liver to regenerate more quickly.
In Europe, milk thistle is often added as extra protection when patients are given medications known to cause liver problems. However, milk thistle failed to prove effective for preventing liver inflammation caused by the Alzheimer's drug Cognex (tacrine).
Milk thistle is also used in a vague condition known as minor hepatic insufficiency, or "sluggish liver."
Milk thistle may also offer some protection to the kidney.
Highly preliminary evidence hints that milk thistle might help reduce breast
In one small, placebo-controlled trial, the topical application of milk thistle with
What Is the Scientific Evidence for Milk Thistle?
As noted above, 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 often yielded mixed results. A 2007 review of published and unpublished studies on milk thistle as a treatment for liver disease caused by alcohol or viral hepatitis concluded that benefits were seen only in low-quality trials, and, even in those, milk thistle did not show more than a slight benefit. 49
Acute Viral Hepatitis
A 21-day, double-blind,
Chronic Viral Hepatitis
Inconsistent evidence exists regarding whether milk thistle is helpful for chronic viral hepatitis B or C.
A double-blind, placebo-controlled study performed in 1981 followed 106 Finnish soldiers with alcoholic liver disease over a period of 4 weeks.
Two similar studies provided essentially equivalent results.
A double-blind, placebo-controlled study of 170 people with alcoholic or non-alcoholic cirrhosis found that in the group treated with milk thistle the 4-year survival rate was 58% as compared to only 38% in the placebo group.
A double-blind, placebo-controlled trial that enrolled 172 people with cirrhosis for 4 years also found reductions in mortality, but they just missed the conventional cutoff for statistical significance.
Protection from Medications That Damage the Liver
Numerous medications can injure or inflame the liver. Preliminary evidence suggests that milk thistle might protect against
The standard dosage of milk thistle is 200 mg 2 to 3 times a day of an extract standardized to contain 70% silymarin.
There is some evidence that silymarin bound to phosphatidylcholine may be better absorbed. 34,35
Warning : Considering the severe nature of liver disease, a doctor's supervision is essential. Also, do not inject milk thistle preparations that are designed for oral use!
Milk thistle is believed to possess very little toxicity. Animal studies have not shown any negative effects even when high doses were administered over a long period of time. 36
A study of 2,637 participants reported in 1992 showed a low incidence of side effects, limited mainly to mild gastrointestinal disturbance.
On the basis of its extensive use as a food, milk thistle is believed to be safe for pregnant or nursing women and researchers have enrolled pregnant women in studies.
No drug interactions are known. However, one report has noted that silibinin can inhibit a bacterial enzyme called beta-glucuronidase, which plays a role in the activity of certain drugs, such as oral contraceptives.
Interactions You Should Know About
If you are taking:
- Medications that could damage the liver, such as acetaminophen, phenytoin (Dilantin), alcohol, and phenothiazines: Milk thistle might be protective for some of these drugs.
- Oral contraceptives
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14. Sonnenbichler J, Scalera F, Sonnenbichler I, et al. Stimulatory effects of silibinin and silicristin from the milk thistle Silybum marianum on kidney cells. J Pharmacol Exp Ther. 1999;290:1375-1383.
16. Lucena MI, Andrade RJ, de la Cruz JP, et al. Effects of silymarin MZ-80 on oxidative stress in patients with alcoholic cirrhosis. Results of a randomized, double-blind, placebo-controlled clinical study. Int J Clin Pharmacol Ther. 2002;40:2-8.
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26. Trinchet JC, Coste T, Levy VG, et al. Treatment of alcoholic hepatitis with silymarin. A double-blind comparative study in 116 patients [translated from French]. Gastroenterol Clin Biol. 1989;13:120-124.
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30. Pares A, Planas R, Torres M, et al. Effects of silymarin in alcoholic patients with cirrhosis of the liver: results of a controlled, double-blind, randomized and multicenter trial. J Hepatol. 1998;28:615-621.
32. Palasciano G, Portincasa P, Palmieri V, et al. The effect of silymarin on plasma levels of malon-dialdehyde in patients receiving long-term treatment with psychotropic drugs. Curr Ther Res. 1994;55:537-545.
39. Giannola C, Buogo F, Forestiere G, et al. A two-center study on the effects of silymarin in pregnant women and adult patients with so-called minor hepatic insufficiency [in Italian]. Clin Ther. 1985;114:129-135.
41. Lucena MI, Andrade RJ, de la Cruz JP, et al. Effects of silymarin MZ-80 on oxidative stress in patients with alcoholic cirrhosis. Results of a randomized, double-blind, placebo-controlled clinical study. Int J Clin Pharmacol Ther. 2002;40:2-8.
44. Gordon A, Hobbs DA, Bowden DS et al. Effects of Silybum marianum on serum hepatitis C virus RNA, alanine aminotransferase levels and well-being in patients with chronic hepatitis C. J Gastroenterol Hepatol. 2006;21:275-80.
47. Huseini HF, Larijani B, Heshmat R et al. The efficacy of Silybum marianum (L.) Gaertn. (silymarin) in the treatment of type II diabetes: a randomized, double-blind, placebo-controlled, clinical trial. Phytother Res. 2006 Oct 30. [Epub ahead of print]
50. Berardesca E, Cameli N, Cavallotti C, et al. Combined effects of silymarin and methylsulfonylmethane in the management of rosacea: clinical and instrumental evaluation. J Cosmet Dermatol. 2008;7:8-14.
Last reviewed April 2009 by EBSCO CAM Review Board
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