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Green Tea and Liver Disease
The liver is a vital organ that performs a
multitude of important bodily functions. These include the breakdown and
detoxification of toxins (including alcohol, drugs and environmental
pollutants), the metabolism of protein, fats and carbohydrates, the
storage of vitamins and minerals, the regulation of blood clotting, the
production of proteins and enzymes and the maintenance of hormone
balance. The liver also filters bacteria out of the blood and makes
bile, which is necessary for proper digestion. Clearly, keeping the
liver strong and well-functioning is essential to good health and it
appears that green tea may be able to help.
Alcohol is one of the biggest enemies of the liver. The
chronic intake of more alcohol than the liver can process causes fatty liver,
alcoholic hepatitis or cirrhosis and may even result in death. To find out if
green tea polyphenols can prevent at least some alcohol-related damage to the
liver, Chinese researchers infused laboratory rats with alcohol for 12 weeks;
some of the rats were also given green tea polyphenols.1 At the end
of the study period, the rats that received the polyphenols had less liver
damage than those receiving alcohol alone. Specifically, there was a lower level
of fat and collagen deposition in the liver and a reduced rate of liver cell
death.
But does green tea have the same effect on the human liver?
A survey of 1,371 Japanese men over the age of 40 found that those who drank
large amounts of green tea, especially more than 10 cups a day, had lower blood
levels of certain markers of liver damage (AST, alanine transferase and ferritin).2
And a 2008 review of ten human studies on green tea consumption and liver
disease found that eight of these studies showed a significantly protective role
of green tea against various liver diseases, including cancer, cirrhosis and
fatty liver disease.3 The remaining two studies also showed a
protective effect, but to a lesser degree. The researchers concluded that, an
increased consumption of green tea may reduce the risk of liver disease.
1Zhang
XG, Xu P, Liu Q, et al. Effect of tea polyphenol on cytokine gene expression in
rats with alcoholic liver disease. Hepatobilliary Pancreat Dis Int
2006;5(2):268-72.
2Imai
K, Nakachi K. Cross sectional study of effects of drinking green tea on
cardiovascular and liver diseases. BMJ 1995;310(6981):693-96.
3Jin
X, Zheng RH, Li YM. Green tea consumption and liver disease: a systematic
review. Liver Int 2008;28(7):990-96.
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Nadine Taylor, M.S., R.D. presents
GreenTeaLibrary.com, the most
comprehensive collection of scientific information describing the
health benefits of green tea.
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