Written by Jianping Liu, Xun Li and the CAM-Cancer Consortium.
Updated May 8, 2012

Green tea (Camellia sinensis)

Does it work?

A total of 12 systematic reviews and/or meta-analyses of epidemiologic studies investigated associations between green tea consumption and the risk of cancer. Details of the included reviews are presented in Table 1.

Cancer in general

Two recent systematic reviews 4-5 and a 2009 Cochrane review 6 concluded that there is insufficient and conflicting evidence to establish an association between green tea consumption and incidence of cancer. In general, inverse associations for green tea consumption and risk of gastrointestinal tract, ovarian, prostate and breast cancer were found. Evidence for a protective role of tea intake on the development of cancers of the lung, liver, colorectum, pancreas, urinary tract, glioma, lymphoma, and leukaemia was, however, insufficient.

Ovarian cancer

Two systematic reviews 7-8 of 18 studies found uniformly inverse association between green tea consumption and ovarian cancer risk.

Prostate cancer

A 2011 meta-analysis 9 of 7 studies investigating the association between green tea and black tea consumption with prostate cancer risk indicated that consumption of green tea may have a protective effect on prostate cancer in Asian populations, especially in Chinese people.

Liver cancer

A 2011 meta-analysis 10 of 13 studies found an inverse association with a borderline significance between tea consumption and primary liver cancer, and green tea consumption was associated with a moderate reduction in risk for primary liver cancer.

Stomach cancer

A 2010 meta-analysis 11 of 18 studies found a reduced risk of stomach cancer with intake of green tea. However, another meta-analysis 12 published in 2009 of 13 studies (9 studies were covered in the 2010 meta-analysis 11) indicated that the highest green tea consumption had no preventive effect on stomach cancer in the meta-analysis of cohort studies and even had an increased risk of stomach cancer using crude data.

Colorectal cancer

A 2006 meta-analysis 13 of 8 studies indicated a reduced risk of colorectal cancer with green tea consumption from combined results. The inverse association was observed only in case-control studies.

Breast cancer

A 2010 meta-analysis 14 of 9 studies found that increased green tea consumption (more than 3 cups a day) was inversely associated with breast cancer recurrence in the analysis of case-control studies but not in the cohort studies.

Lung cancer

A 2009 meta-analysis 15 of 12 studies indicated a borderline significant association between highest green tea consumption and reduced risk of lung cancer, and an increase in green tea consumption of two cups/day was associated with an 18% decreased risk of developing lung cancer.

Citation

Jianping Liu, Xun Li , CAM-Cancer Consortium. Green tea (Camellia sinensis) [online document]. http://www.cam-cancer.org/CAM-Summaries/Herbal-products/Green-tea-Camellia-sinensis. May 8, 2012.

Document history

Summary last updated and revised in May 2012 by Jianping Liu and Xun Li.
Summary fully updated and revised in April 2012 by Jianping Liu and Xun Li.
Summary first published in September 2005, authored by Jianping Liu.

References

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  6. Boehm K, Borrelli F, Ernst E, Habacher G, Hung SK, Milazzo S, Horneber M. Green tea (Camellia sinensis) for the prevention of cancer. Cochrane Database of Systematic Reviews 2009, Issue 3. Art. No.: CD005004. DOI: 10.1002/14651858.CD005004.pub2.
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  23. Golden EB, Lam PY, Kardosh A et al. Green tea polyphenols block the anticancer effects of bortezomib and other boronic acid-based proteasome inhibitors.Blood. 2009;113(23):5927-37.
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