Washington, February 3 : Herbal product silymarin (milk thistle) does not affect the hepatitis C virus (HCV) or alanine aminotransferase (ALT) levels in the blood, say researchers.
The findings are based on a comparison between clinical data of silymarin users and non-users, gathered through a survey of patients with chronic hepatitis C.
All patients in the survey were those who had 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.
The researchers asked participants about their 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 varieties. Silymarin was by far the most common.
Upon 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.
The product did not even alter serum ALT levels, indicating no effect on hepatic inflammation.
The authors also observed that silymarin users reported less fatigue, nausea, liver pain, anorexia, muscle and joint pain and better general health than non-users.
However, they insist that 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.
According to them, 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.
The study has been published in Hepatology, a journal published by Wiley and Sons on behalf of the American Association for the Study of Liver Diseases (AASLD).