Research published in the Journal of Nutrition (February 2008; Volume 138, pages 323–331) examined whether green tea extract may have a protective effect on the liver. Fatty liver is commonly seen in obesity, type 2 diabetes, and alcoholism. It is often asymptomatic, but over time it can lead to inflammation, liver cell damage, and, in severe cases, liver failure.
The study was conducted using mice genetically bred to be obese. The animals were divided into groups and fed diets containing either no green tea extract, 1% green tea extract, or 2% green tea extract for six weeks. One notable finding was that the mice receiving green tea extract weighed significantly less than the control group. Mice given 1% green tea extract weighed approximately 11% to 20% less than controls, while those given 2% green tea extract weighed 23% to 25% less.
Liver cell damage is commonly assessed by measuring the enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST), which are released into the blood when liver cells are injured or destroyed. Supplementation with green tea extract reduced ALT levels by 20% to 41% and reduced AST levels by 22% to 33%, suggesting a protective effect on liver tissue in this animal model.
