Green tea may help to prevent liver damage. However, these benefits may only apply to the brewed drink form of green tea. Some evidence points to green tea extract supplements having a negative effect on the liver. Nonetheless, drinking cups of green tea appears to offer overall health benefits to the liver and to other areas of your body. Always speak with your doctor before taking green tea as a treatment for any liver conditions.
Liver Disease
In a 2008 study published in "Liver International," researchers reviewed all available scientific papers on liver disease and green tea between the years 1989 and 2007. From the results of 10 of the most reliable papers they concluded that drinking green tea may lower your chances of developing liver disease. Drinking 10 cups of green tea per day appears to have a particular benefit -- but such large daily doses of caffeine and green tea over time may be unsafe.
Liver Cancer
Green tea may help to inhibit tumor formation in the liver, according to the National Cancer Institute. Naturally occurring chemicals called polyphenols found in very high doses in green tea have been linked with reduced cancer risk. The University of Maryland Medical Center also points out that the polyphenols known as catechins may help to reduce liver inflammation from hepatitis when consumed in concentrated doses.
Green Tea Supplements
Some health stores sell green tea extract in the form of supplement tablets. A 2006 review published in "Liver Transplantation" noted that commercially available green tea supplements may trigger acute liver toxicity. However, the report doesn't list doses or supplement concentrations. The NYU Langone Medical Center lists typical green tea supplement doses as between 100 and 150 mg three times per day. If you have any existing liver problems, or plan to start taking green tea extract, speak to your doctor before proceeding.
Considerations
Green tea also contains caffeine. In very high doses caffeine has a toxic effect on the liver. However, a fatal dose is around 10 to 14 g, according to the MedlinePlus website. You're unlikely to drink this much caffeine via green tea. To minimize the impact of green extract supplements you should take them alongside food. If you have liver damage already avoid green tea unless otherwise advised by a medical professional.
References
- "Liver International"; Green Tea Consumption and Liver Disease: A Systematic Review; X. Jin, et al.; Aug. 2008
- University of Maryland Medical Center; Green Tea
- NYU Langone Medical Center; Green Tea; Feb. 2007
- "Liver Trasplantation"; Acute Liver Failure Induced by Green Tea Extracts: Case Report and Review of the Literature; Dec. 2006
- MedlinePlus; Green Tea; May 24, 2011
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