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Milk Thistle: An Old Herb for the Liver with Potential New Uses

written by: cra8051 • edited by: Diana Cooper • updated: 6/27/2011

Milk Thistle, used since a Greek doctor serving Roman armies prescribed it for liver diseases like cirrhosis, may reduce LDL and help in other conditions such as acne, irritable bowel syndrome and psoriasis. It may inhibit the growth of cancer cells and ease side effects of drugs for Parkinson’s.

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    Milk Thistle in History

    The seeds of the milk thistle plant (Silybum marianum) have been used for centuries for their beneficial effect on the liver. The plant is native to the Mediterranean but grows in other areas as well. Early settlers brought it to America. It is found now in different areas of the United States, especially in California. The plant grows to a height of five feet, with purple flowering heads. In the 1920’s and 1930’s German scientists brought a resurgence of interest in the plant when they actively began using it to treat chronic liver disease, acute hepatitis and jaundice. Advances in clinical research methods identified a component of milk thistle called silymarin as the active ingredient.

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    Milk Thistle photographed by Lestat (Jan Mehlich) and provided free for commericial use under GFDL and Creative Commons Attribution ShareAlike 2.5 license.

    Milk Thistle
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    Benefits are Mixed but Side Effects Are Low

    As the Complementary and Alternative Medicine (CAM) field became more acceptable, more studies were done on silymarin. At this time, results are mixed; however, there is some research that seems to bear out the claims for this herb. There are a few reports of minor digestive side effects or allergic reactions, but milk thistle generally is considered safe if used within approved dosage limits.

    Research indicates silymarin may have important therapeutic benefits beyond toxic liver conditions. One study found evidence the extract can inhibit growth of cancer cells. [Source: J. Post-White, E.J. Ladas, and K.M. Kelly, “Advances in the use of milk thistle (Silybum marianum),” Integrative Cancer Therapies 6(2) (June 2007), 104-109.]

    Other suggested uses include acne, irritable bowel syndrome, psoriasis, and to mitigate the effects of drugs used to treat Parkinson’s and ovarian cysts.

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    What is Milk Thistle Used for Today?

    A very recent report documents the positive effect on low-density lipoprotein, suggesting the operative elements in the herb are flavonolignans. [Source: S. Wallace, et al., Milk thistle extracts inhibit the oxidation of low-density lipoproteins (LDL) and subsequent scavenger receptor-dependent monocyte adhesion,” Journal of Agricultural and Food Chemistry 56(11) (June 11, 2008), 3966-3972.] These compounds, as the word suggests, are flavonoids, already known to have beneficial antioxidant effects, bound to lignans, phytoestrogens in plants.

    In 2006 similar research found the same results in reductions in blood tests that measure effective control of adult-onset diabetes (Type-2). There was a “significant decrease in glycosylated hemoglobin (HbA(1)c, fasting blood glucose (FBS), total cholesterol, LDL, triglyceride SGOT and SGPT levels” in patients who were treated with a 200 mg tablet three times a day compared to a control group. Both groups received the same conventional therapy as well. [Source: H. F. Huseini, 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," Phytotherapy Research 20(12) (December 2006):1036-1039.]

    Some people also brew and drink a milk thistle tea for supposed health benefits.

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    As with any herbal treatment, particularly for potentially serious diseases, patients should always check with a medical practitioner before embarking on a new therapy. Women using birth control pills are cautioned that milk thistle may reduce effectiveness of the pills. Diabetics should monitor blood sugar levels carefully while using this herb. [Source: Phyllis A. Bach, Prescription for Herbal Healing (New York: Avery, 2002), pp. 95-06.]

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