The Silybum marianum plant goes by many different names, including Scotch thistle, holy thistle, Mary thistle, variegated thistle, and milk thistle. The plant is native to Southern Europe and Asia but has spread across much of the world. It’s considered an unwelcome plant in many gardens, where it can quickly grow to be a large and thorny invader.
The fruit and seeds of the milk thistle plant have been used in some traditional medicine for centuries. Most commonly, milk thistle was thought to be good for treating disorders of the liver and gallbladder.
These days milk thistle tea is sometimes marketed as a cleansing, ultra-healthy drink. Unfortunately, research milk thistle's historic use as a treatment for liver disease and cirrhosis has produced conflicting and inconclusive results.
Like all teas, the majority of a cup of milk thistle tea is water. While some of the components of the steeped milk thistle make it into the liquid, these nutrients are extremely dilute.
Milk thistle tea is not a significant source of any major nutrients, vitamins, or minerals.
Potential Health Benefits of Milk Thistle Tea
The standardized extract of milk thistle is referred to as silymarin or silimarin. Several studies have looked into the potential health benefits of milk thistle extract. Some of this research has produced encouraging results.
However, none of this research specifically studied milk thistle tea. Tea has different concentrations of milk thistle’s active substances than standardized silymarin.
Multiple studies have been conducted on humans to examine the effects of silymarin on people with type 2 diabetes.
One specifically examined participants who had both diabetes and alcoholic liver cirrhosis. A daily dose of 600 mg of silymarin for six months reduced fasting blood glucose and mean daily glucose levels without increasing hypoglycemic episodes. Another study with 25 participants demonstrated that silimarin seems to reduce blood glucose levels through mechanisms unrelated to insulin production.
The benefit of lowering blood sugar can also be a risk to people with diabetes. As such, milk thistle tea should be consumed with caution.
Studies have indicated that milk thistle extracts may be able to suppress prostate cancer cell growth. Further research with clinical trials is needed to better understand milk thistle’s potential for treating or preventing cancer.
Potential Risks of Milk Thistle Tea
Generally, milk thistle tea is safe to drink in moderation. There are a few known associated health risks, however.
Milk Thistle Allergy
Severe allergic reactions have been reported with milk thistle. People most likely to exhibit milk thistle allergies are those known to be allergic to other members of the asteraceae family. This includes ragweed, daisies, marigolds, and chrysanthemums.
Milk thistle tea may interfere with the effectiveness of several medications, including the antibiotic metronidazole, the hepatitis C drug simeprevir, and the immunosuppressant sirolimus. People taking any of these medications should avoid drinking milk thistle tea.