Especially at this time of year, the Internet is awash with articles, adverts and testimonials claiming that milk thistle is the answer to the after-effects of alcohol overindulgence.
The general recommendation is that you should take a milk-thistle pill before you start drinking to reduce all of those negative side-effects the day after. But is there any truth to this widely held belief?
What the science says
Surprisingly, there do not appear to have been any scientific studies to assess the effectiveness of milk thistle for either preventing or treating hangovers. However, a number of clinical trials have looked at whether the herb can treat alcohol-related liver disease. The results of some of these studies suggest that silymarin-a type of polyphenol believed to be the major active constituent of milk thistle-can be useful in the management of early or progressive liver damage when taken for one to six months.
In one such trial, nearly 100 patients with alcoholic liver disease (ALD) were randomly allocated to receive either silymarin or a placebo for four weeks. Alcohol consumption was strictly prohibited during the trial, and several indicators of liver damage were assessed.
The results showed that silymarin was associated with a highly significant reduction in levels of alanine transaminase (ALT) and aspartate transaminase (AST)-liver enzymes that are commonly increased in patients with ALD and so are used as indicators of liver damage. The silymarin group was also more likely
to show other signs of improved liver health compared with the placebo group, including normalization of liver tissue changes due to the disease (Scand J Gastroenterol, 1982; 17: 517-21).
In another trial, 36 patients with chronic ALD were given either sily-marin at a dose of 420 mg/day or a placebo for six months. Here again, the researchers noted a number of significant improvements in terms of liver damage in those taking silymarin, including normalization of ALT and AST levels, and improvement in their liver biopsy examinations.
“These results indicate that sily-marin exerts hepatoprotective [liver-protective] activity and is able to improve liver functions in alcoholic patients,” the researchers concluded (Orv Hetil, 1989; 130: 2723-7).
The same dose of silymarin was tested in a French trial of 116 patients with alcoholic hepatitis (liver inflam-mation). In this case, 57 patients were given silymarin and 59 took a placebo every day for three months. At the end of the trial, silymarin was found to significantly alter the course of the disease, as determined by biological and histological (tissue) parameters.
Curiously, however, significant improvements were seen in both the silymarin and placebo groups, leading the authors to conclude that the dosage of 420 mg/day was “not clinically relevant in the treatment of moderate alcoholic hepatitis” (Gastro-enterol Clin Biol, 1989; 13: 120-4).
Nevetheless, yet another study-this time in Austria-assessed the potential value of 420 mg/day in 170 patients with liver cirrhosis, roughly half of whom had alcoholic cirrhosis. After an observation period of more than three years (41 months on average), the Viennese researchers reported a 58-per-cent survival rate in those taking silymarin compared with a 39-per-cent rate of survival in those taking the placebo-a difference that was statistically significant. Further analysis of various patient subgroups revealed that silymarin treatment was also effective in patients with alcoholic cirrhosis (J Hepatol, 1989; 9: 105-13).
It’s likely that these studies-along with evidence from animal studies showing that silymarin can protect against alcohol-induced liver damage (Indian J Med Res, 2006; 124: 491-504)-may have fuelled the belief that milk thistle can help to prevent the after-effects of a night of heavy drinking.
However, the fact that these studies suggest that milk thistle can be of benefit in the case of alcoholics doesn’t necessarily mean that healthy moderate or occasional drinkers will experience the same effects. Moreover, even if milk thistle could protect healthy livers against the harmful effects of alcohol, this still doesn’t tell us whether the herb can help with a hangover.
Nevertheless, a recent extensive review of silymarin-assessing its basic pharmacology through to its clinical applications-can shed some light on the matter. As the authors, based in Pondicherry, India, have pointed out, “Silymarin has no direct effect on ethanol [alcohol] metabolism and has no role in reducing ethanol levels or the rate at which ethanol is removed from the body” (Indian J Med Res, 2006; 124: 491-504). This suggests that it’s unlikely that milk thistle would be of any use for a hangover.
However, a study of a different herb-Opuntia ficus indica, or prickly pear-reported that the symptoms of hangover may be largely due to inflammation triggered by impurities in alcoholic beverages and by the byproducts of alcohol metabolism in the body. This study found that prickly pear taken five hours before the consumption of alcohol significantly reduced hangover symptoms and their severity in healthy volunteers compared with a placebo, and appeared to work via an anti-inflammatory effect (Arch Intern Med, 2004; 164: 1334-40). As silymarin is also known to have anti-inflammatory properties, this could perhaps result in similar hangover-reducing effects. Still, until such a study is conducted with silymarin itself, we just don’t know if this is the case.
Is it safe?
The bottom line is that, as yet, there’s no proof to show that milk thistle can either prevent or treat a hangover. However, if you still want to give it a go, it’s unlikely to do you any harm.
Milk thistle is usually used as a standardized extract (containing 70- to 80-per-cent silymarin) in the form of capsules, with 100-300 mg three times a day being the typical adult dose. Human studies have shown that silymarin is non-toxic and without side-effects when given to adults in divided doses up to 900 mg/day. At higher doses of more than 1500 mg/day, silymarin may produce a laxative effect, which could be due to increased bile flow and secretion. Mild allergic reactions have also been noted (Indian J Med Res, 2006; 124: 491-504). In addition, if you’re taking any other medications or are pregnant, it may
be better to consult a qualified prac-titioner before trying milk thistle.
Joanna Evans
New uses of milk thistle
Although milk thistle has a long history of use for liver diseases, new evidence suggests that it may also help in a range of other conditions.
o Alzheimer’s disease. A recent study from Japan has found silymarin to be a promising agent for the prevention of this progressively debilitating brain disease. Using a mouse model of Alzheimer’s, silymarin suppressed the formation of fibrils (fine fibres) by amyloid beta-protein-at least in a test tube. These fibrils are thought to play a key role in the development of the disease (Biosci Biotechnol Biochem, 2010 November 7; Epub ahead of print). However, such results may not necessarily be seen in humans.
o Cancer. Laboratory studies have found that silymarin and its main constituent, silibinin, have powerful anticancer effects (Anticancer Agents
Med Chem, 2010; 10: 186-95). One study involving both test tubes and animals showed that silibinin can suppress the growth and induce the cell death (apoptosis) of human advanced colorectal cancer cells (Mol Cancer Ther, 2009; 8: 2366-74).
In addition, a recently published study has examined the efficacy of a combination of silymarin and selenium in 37 men who had undergone radical prostatectomy. The results after six months showed that the silymarin-selenium supplement had significantly reduced two markers of fat metabolism-low-density lipoproteins (LDLs, the ‘bad’ fats) and total cholesterol-known to be associated with prostate cancer progression (Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub, 2010; 154: 239-44).
o Diabetes. In a randomized, dou
ble-blind, placebo-controlled trial-the ‘gold standard’ for scientific evaluation-51 patients with type 2 diabetes were given either silymarin (200 mg three times a day) or a placebo together with conventional therapy for four months. At the end of the study, the researchers noted several significant improvements in the silymarin group, including reduced fasting blood glucose and lower levels of total cholesterol. “In conclusion, silymarin treatment in type II diabetic patients for 4 months has a beneficial effect on improving the glycemic profile,” the researchers said (Phytother Res, 2006; 20: 1036-9).
o Skin disorders. Silymarin also appears to protect the skin against ultraviolet (UV) radiation-induced damage, which can cause sunburn, premature skin ageing and skin cancer (Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub, 2005; 149: 29-41). However, clinical (human) trials are needed. Nevertheless, the evidence so far shows that silymarin has powerful antioxidant and anti-inflammatory properties, which would make it a valuable skin-protecting agent (Int J Oncol, 2010; 36: 1053-60).
o Heart disease. The latest laboratory evidence suggests that milk thistle may have a role to play in heart health, although the results need to be confirmed in clinical trials. Researchers at the University of Arkansas discovered that silymarin significantly protected LDL cholesterol against oxidation, thought to be a major contributor to atherosclerosis-the build-up of plaque in the arteries (J Agric Food Chem, 2008; 56: 3966-72).
In another, test-tube study, Chinese scientists reported that silibinin protected against inflammation, fibrosis and cardiac hypertrophy-thickening of the heart muscle, a major cause of heart failure (J Cell Biochem, 2010; 110: 1111-22).
VOL. 21 NO. 10
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