Silymarin (Milk Thistle) Does Not Affect Hepatitis C Virus Activity or ALT Levels in HCV Patients, but Users Report Fewer Symptoms and Better Quality of Life than Non Users

Many HCV patients use the herb silymarin (milk thistle), an alternative therapy for HCV, in addition to or instead of standard treatment for chronic hepatitis C virus infection. In a survey of patients with chronic hepatitis C who participated in a National Institute of Diabetes and Digestive and Kidney Diseases-sponsored long-term treatment trial for patients who had failed to respond previously to antiviral therapy, approximately 40% acknowledged to interviewers at the time of enrollment that they were currently using or had in the recent past used herbal products for health purposes.
This information was somewhat surprising because these were patients with advanced liver disease who were clearly committed to conventional antiviral treatment for chronic hepatitis C, having been so treated previously, some on more than one occasion, but because they had failed to respond, were now willing to accept treatment again with pegylated interferon for another 3 and a half years.

Among those who were or had used alternative therapies, silymarin was the product of choice either on its own or together with other herbal products, representing 72% of all the herbals taken.

These study results appear in the February 2008 issue of Hepatology, published by Wiley & Sons on behalf of the American Association for the Study of Liver Diseases (AASLD). The article was is also available online at Wiley Interscience.

These results do not come from a rigorous scientific study because the products used were self-administered by the patients who entered the trial and no information was obtained on the duration or dose of the herbal taken. Still, in comparing users with non-users, while no difference was found for blood ALT or HCV levels between the two groups, the herbal users did report somewhat fewer symptoms and a better quality of life.

The current recommended treatment for patients with HCV infection is combination therapy with pegylated interferon and ribavirin. However, it leads to a sustained virological response (SVR) in only a third to a half of all patients with the predominant form of the infection in the U.S., namely genotype 1, and it can cause unpleasant and sometimes serious side effects.

HALT-C Trial

The NIH study, referred to as the Hepatitis C Antiviral Long-Term Treatment against Cirrhosis (HALT-C) Trial, was designed, therefore, to treat persons with advanced chronic hepatitis C who had failed previous antiviral therapy with the hope that the long-term treatment would reduce progression of the chronic liver disease even if it did not affect the virus itself.

The reason for interviewing enrollees in the trial was to determine the extent of use of alternative therapies in this committed group, since the popularity of herbal products has increased in the U.S., many HCV patients choosing to supplement, or even replace, the standard treatment with herbals. Silymarin (milk thistle extract) has been the most popular option for people with liver disease. Although it is the most frequent product utilized, silymarin has not been rigorously studied using accepted scientific approaches, and therefore such studies are clearly required and warranted.

For the present survey, researchers interviewed all HALT-C participants on past and current use of all prescription and non-prescription drugs, including herbal medications, dietary supplements and other botanical products. Of 1145 study participants, 56 percent said that they had never used herbal products, while 23 percent were using them currently, some 60 different articles. Silymarin was by far the most common. Usage was higher among men, among non-Hispanic whites, and among the more highly educated. Interestingly, the researchers also found geographic disparities in silymarin usage. It was most popular in Colorado, Michigan and Southern California and least popular in Maryland and Massachusetts.

Conclusions

In comparing the clinical data of silymarin users and non-users, the researchers found that "the levels of HCV RNA were not significantly different between silymarin users and non-users," indicating no effect on virus activity. Similarly, the product did not alter serum ALT levels, indicating no effect on hepatic inflammation. However, after adjusting for covariates, the data showed that silymarin users reported less fatigue, nausea, liver pain, anorexia, muscle and joint pain and better general health than non-users.

The better scores in a small number of symptoms among silymarin users compared to non-users are insufficient to support the value of this alternative therapy, the authors conclude. Compelling information can come only if a scientifically valid study is performed. "Currently in progress, therefore, is a properly designed prospective, randomized, controlled trial in which a fully characterized, purified and standardized silymarin formulation is being evaluated," they report.

This trial is supported by the National Center for Complementary and Alternative Medicine (NCCAM) and by NIDDK, NIH.

L Seeff, T Curto, G Szabo, and others. Herbal Product Use by Persons Enrolled in the Hepatitis C Antiviral Long-Term Treatment against Cirrhosis (Halt-C) Trial. Hepatology 47(2): 605-612. February 2008.