Green Tea Lowers Liver Cancer Risk: How Many Cups Per Day?

Research indicates that high green tea consumption is associated with a reduced risk of liver cancer, particularly among populations in Asia.

Findings suggest that the most significant protective effects are observed in individuals with the highest levels of daily intake.

Consumption Levels and Risk Reduction

An editorial published in April 2017 in the journal Hepatobiliary Surgery and Nutrition discussed a meta-analysis that calculated a summative relative risk (RR) of 0.88.

The analysis showed a significant reduction of liver cancer specifically in the group with the highest green tea consumption, defined as more than 5 cups per day.

Data from three different studies considering an intake of 5 or more cups per day showed varying relative risks of 0.58, 1.44, and 0.90.

one study reported a relative risk of 0.53 for individuals consuming 10 or more cups per day.

The Role of Catechins and Antioxidants

The potential protective role of green tea is attributed to its polyphenolic antioxidants, specifically catechins.

Green tea accounts for 20% of total tea production worldwide and is produced by heating, steaming, or pan-frying fresh tea leaves at high temperatures.

These specific processing methods result in minimal oxidation when compared to the preparation of black tea.

This lack of oxidation allows for the better preservation of the main tea polyphenols, such as catechins, which animal and in vitro studies indicate may play a role in preventing carcinogenesis.

Public Health Context in Asia

Hepatocellular carcinoma is a major preventable disease with a high prevalence and incidence in several Asian countries.

Due to this prevalence, researchers have analyzed the chemopreventive potential of green tea within these specific regions.

A June 2015 meta-analysis published in the International Journal of Clinical Experimental Medicine also sought to evaluate the body of evidence regarding green tea consumption and its effectiveness in reducing the risk of liver disease.

Other research combining case-control and cohort studies has previously suggested that high green tea intake might be associated with a lower risk of liver cancer.