Green tea may help your liver -- or it may not, depending on how you consume it and in what quantities. While drinking a moderate amount of green tea may reduce the risk of liver cancer and other liver disorders, taking large amounts of green tea supplements could have toxic effects on your liver.
Green tea, an unfermented tea, contains large amounts of antioxidants called polyphenols. Antioxidants can reduce cell damage by attacking free radicals, molecules created by environmental toxins as well as by normal body functions. Antioxidants may neutralize damage done to cells that can lead to aging or to diseases such as cancer or heart disease.
Several studies have shown green tea has potential benefits in treating or preventing liver disease. A large Japanese study reported in the 2009 issue of "Cancer Causes and Control" found that drinking green tea was inversely related to the risk of developing liver cancer. Men who drank five or more cups per day had 37 percent less risk than those who drank one or no cups per day, while women reduced their risk by 50 percent. A review of 10 studies reported in "Liver International" on the effects of green tea on liver disease reported that eight out of the 10 found green tea had a protective effect against liver disease.
Green tea supplements contain concentrated amounts of polyphenols, including epigallocatechin-3-gallate, also known as EGCG. Consumption of between 700 and 2,000 milligrams per day led to toxic liver effects in nine anecdotal case reports, according to an article published by researchers from Rutgers, the State University of New Jersey in the March 2007 issue of "Chemical Research and Toxicology." When patients stopped taking the supplements, their liver problems disappeared.
If you enjoy drinking green tea, drinking even up to 10 cups a day appears to have positive benefits on your liver, according to the University of Maryland. If you have or are at risk of developing liver disease, stick with tea and skip the green tea supplements, which can contain up to 50 times the amount of polyphenols as a single cup of tea.
- University of Maryland Medical Center; Green Tea; September 2010
- "Cancer Causes and Control"; Green Tea Consumption and the Risk of Liver Cancer in Japan: The Ohsaki Cohort Study; A. Ui, et al.; December 2009 ;
- "Liver International"; Green Tea Consumption and Liver Disease: A Systematic Review; X. Jin, et al.; August 2008
- New Scientist; Green Tea Can Be Harmful in Large Quantities; May 2007
- "Chemical Research in Toxicology"; Possible Controversy over Dietary Polyphenols: Benefits vs Risks; Joshua Lambert, et al.;March 2007