Research appearing in the Journal of Nutrition (February 2008, Volume 138, Pages 323-331) shows that extracts from green tea may have a protective effect on the liver. Fatty liver is seen in obesity, type-2 diabetes, and alcoholism. It does not have any symptoms, but it can lead to inflammation and cell destruction and may result in liver failure.
The research was done on mice genetically bred to be obese. They were divided into groups and fed a diet containing either zero, 1%, or 2% green tea extract for six weeks. One thing worth noting is that the mice supplemented with the green tea extract weighed between 11% and 25% less than the controls that were not given the substance. The group given 1% green tea extract weighed between 11% and 20% less than the controls. The group given 2% green tea extract weighed between 23% and 25% less than controls.
When liver cells die, they release enzymes called alanine aminotransferase and aspartate aminotransferase. Supplementation with the green tea extract reduced alanine aminotransferase between 20% and 41%; and it reduced aspartate aminotransferase by 22% to 33%.