Green tea comes from the Camellia sinensis plant, and can be made into a beverage or an extract. Black and green tea come from the same plant, with green tea made from unfermented leaves and black tea made from fermented. Green tea may have beneficial effects on the liver, although it isn't a good idea to drink large amounts of it. You should limit your consumption of green tea to no more than 5 cups per day due to the caffeine it contains, recommends MedlinePlus.
Liver Function Markers
A study published in "The Journal of Nutrition" in January 2009 found that consumption of high levels of green tea extracts did not affect markers of liver function in healthy men. The green tea extract consumed in the study was approximately equivalent to consuming between 6 and 8 cups of green tea per day. Although a few previous studies using mice and isolated case studies suggested that green tea might increase the risk for liver problems, the study authors noted that it is likely these adverse liver reactions were at least partly due to other, unrelated factors, such as genetics or other health problems, and not simply green tea consumption.
Liver Function Benefits
Despite the isolated case studies of liver toxicity that may be connected to green tea consumption, evidence points to a protective effect of green tea consumption on the liver, with green tea potentially lowering your risk for liver disease, noted a review article published in "Liver International" in May 2008 that analyzed the results of 10 different studies on green tea and liver function.
Other Potential Benefits
Green tea contains caffeine, so it can make you more alert. Preliminary research shows green tea may also lower your risk for certain types of cancer, lower your cholesterol and reduce your risk for Parkinson's disease, according to MedlinePlus. Other potential benefits include reducing inflammation in inflammatory bowel disease, lowering your risk for diabetes and helping with weight loss, notes the University of Maryland Medical Center.
If you are pregnant or suffer from anemia, heart conditions, bleeding disorders, anxiety, osteoporosis, glaucoma or diarrhea, you should limit your consumption of green tea even further, since caffeine can worsen these conditions. Green tea may also interfere with certain medications, so you should speak to your doctor before taking green tea extract or drinking large amounts of green tea.
- MedlinePlus: Green Tea
- University of Maryland Medical Center: Green Tea
- Liver International: Green Tea Consumption and Liver Disease: A Systematic Review
- Journal of Nutrition: Daily Consumption of an Aqueous Green Tea Extract Supplement Does Not Impair Liver Function or Alter Cardiovascular Disease Risk Biomarkers in Healthy Men