Milk thistle

Sylimarin, Sylibum marianum

Milk thistle is a thistle with many medicinal properties. Traditionally it has been used mainly to support liver function and treat liver problems, but it also has anti-cancer effects and has positive effects on immunity, heart and blood vessels, diabetes, sports performance and breastfeeding support.

Description

Milk thistle is a species of thistle that grows to a height of 30-200 cm. It has typically pinnately lobed leaves with spiny edges and milky white veins (probably the origin of the English name milk thistle) and large reddish-purple flowers. The fruit are shiny, brown-spotted achenes with white fuzz. Milk thistle probably originated in the Mediterranean, but it has spread over time not only throughout most of Europe, but has also been found in North America, Hawaii, Colombia, Australia and New Zealand. In phytotherapy, the fruit is most often collected just before maturity and ground into a fine powder, and the leaves and root are also used to a lesser extent. A standardised extract of milk thistle is known as sylimarin. (1-3)

History

In traditional phytotherapy, milk thistle has been used since ancient times, especially for the treatment of liver diseases. Its use is mentioned in ancient Egyptian texts, and the Roman philosopher and naturalist Pliny the Elder (23-79 AD) also wrote about it. Its use in liver disorders is also mentioned by the English herbalist Nicolas Colpepper (1616-1654) and the Swiss physician Albrecht von Jaller (1708-77).

Healing effects

The main active ingredient of milk thistle is silymarin, which is actually a complex of several substances belonging mainly to flavonolignans and flavonoids. The best studied of these is silibin, sometimes also called silibinin. (3)

In traditional phytotherapy, milk thistle is mainly used to treat liver, gallbladder, stomach and metabolism, viral hepatitis and less so in gynaecological and lung diseases. However, its effects are quite extensive, as the mechanisms by which it acts on the body are numerous. It has even been shown to have epigenetic effects – in particular, silibinin can effectively regulate the activity of a number of important genes (especially by affecting DNA methylation and histone acetylation), which has applications for example in the prevention and treatment of cancer. In addition, it has strong antioxidant and anti-inflammatory effects.(2-4)

Liver

In the field of phytotherapy, milk thistle is mainly associated with the liver, and its significant positive effect on this organ has been confirmed by a number of scientific studies. For example, it is very effective in protecting the liver from the effects of toxic chemicals – the silibinin it contains is thought to displace toxins that try to bind to the liver (including alcohol). It even acts as an antidote for some poisonings, such as greenfly poisoning. It also promotes liver regeneration, stabilises liver cell membranes and protects them from free radical damage (3, 5-8, 13).

It has also been shown to have a positive effect in cirrhosis of the liver, acute and chronic hepatitis or jaundice (including hepatitis C) and alcoholic hepatitis, and can be used prophylactically with drugs that are thought to have a possible negative effect on the liver. (3, 15)

Milk thistle is also applied in a problem called small liver insufficiency or popularly “slow liver”. This is a mildly impaired liver function, which is manifested, for example, by fatigue, malaise, pain under the ribs, constipation, unhealthy skin appearance, and possibly allergies.

Tumour diseases

Thanks to its effects on key epigenetic reactions, milk thistle (especially the silibin) can influence some processes related to the development of cancer. In particular, it affects the cell cycle, apoptosis (programmed cell death) and signalling pathways related to cell division. It has been shown to be effective in cancers such as prostate, liver, pancreatic and colon cancer and may also help to mitigate the negative effects of cancer treatment. However, there have been few studies on human volunteers in this area, with animal studies predominating. However, due to its estrogenic effect, it is not recommended for breast and ovarian cancer (4,16, 17, 33).

Diabetes

Some studies have shown that milk thistle can also be effective for type 2 diabetes. It helps to reduce insulin resistance, improve blood glucose control and prevent complications such as diabetic nephropathy. (10, 24, 25)

Breastfeeding support

In traditional phytotherapy, milk thistle is sometimes recommended to support lactation and its effectiveness in this regard has been confirmed by some research. For example, when a group of breastfeeding women took 420 mg of silymarin for 63 days, they experienced a 63% increase in milk production compared to the placebo group (18).

Alzheimer’s and Parkinson’s disease

In traditional phytotherapy, milk thistle is sometimes used to treat Alzheimer’s and Parkinson’s disease. Indeed, animal studies have shown that it could prevent cognitive decline thanks to its antioxidant and anti-inflammatory properties, and it has also been shown to reduce the formation of so-called amyloid plaques, which are clumps of proteins in the brain that are characteristic of Alzheimer’s disease. However, clinical studies to confirm this effect in humans are lacking (19-22).

Acne

Probably the combination of anti-inflammatory and antioxidant effects of milk thistle is behind its effectiveness in treating acne. In a study in which volunteers took 210 mg of silymarin daily for 8 weeks, they experienced an average 53% reduction in acne lesions (23).

Immunity

Milk thistle also has a significant immunomodulatory effect. It is not only used in immunodeficiency, but can also have a positive effect in autoimmune diseases (26, 27).

Sports performance

Taking milk thistle may be particularly useful for endurance athletes. It improves glucose and fat metabolism and the breakdown of lactate (lactic acid). Studies in which experimental rats were food-motivated to lift progressively increasing loads also noted an increase in strength performance along with weight loss (without loss of muscle mass) when adding silymarin to the diet, suggesting that milk thistle might also be useful for weight loss (28).

Heart and blood vessels

Sylimarin has a positive effect especially on cholesterol and triglyceride levels in the blood. It affects the metabolism of fats, helps to reduce the production of cholesterol in the liver and its absorption from food in the intestines, and increases the rate of conversion of cholesterol to other compounds. In addition, laboratory animal studies have shown that its administration to individuals with high blood lipid levels prevented the formation of atherosclerotic plaques in their blood vessels. Research examining a group of young healthy men also showed a reduction in serum cholesterol, an increase in HDL cholesterol, along with an increase in the antioxidant capacity of the blood after 60 days of use (30, 31).

Use and contraindications

The recommended dose is 200 mg 2-3 times a day in the case of an extract standardized to contain 70% silymarin. (3)

Although some of the components of milk thistle are mildly toxic, animal studies have not shown any significant negative effects even with long-term administration of high doses. A study of more than 2 600 volunteers showed a very low incidence of adverse effects, which were also very mild (mostly digestive problems). Pregnant women were included in this study, as it is generally believed that milk thistle is safe during pregnancy and breastfeeding, but caution is still warranted when using it during this period (and with young children) (11, 12).

Drug interactions are rather uncommon, but caution is needed for example with antidiabetic drugs, blood thinners (Warfarin), Diazepam, some immunosuppressants, antibiotics and hepatitis C drugs. It is always advisable to consult a doctor if you are taking any medication. (15)

Suitable combinations

Liver: thistle + chicory (2), thistle + burdock (2), thistle + curcumin (34), thistle + vitamin E (34), quercetin (36)

Cancer: milk thistle + curcumin (33)

Stomach: milk thistle + benedict (2)

Breastfeeding: milk thistle + benedict

Sports performance: milk thistle + vitamin C (28)

Diabetes: milk thistle + barberry (32), milk thistle + boswellia (35), milk thistle + curcumin