A recently published small study (1) has found that men with prostate cancer who consumed an active green tea supplement had significant reductions in biological-markers predictive of prostate cancer progression.
Green tea has become an incredibly popular drink and supplement and an increasing number of studies are being published with regards its health benefits. The number of current human studies investigating the relationship between green tea and prostate cancer is small. This study (1) was preliminary but informative. It involved just 26 men aged 41-72 years old who were diagnosed with prostate cancer and due to undergo radical prostatectomy. The trial looked to determine the effects of short-term supplementation with the active compounds found in green tea on biological-markers in patients diagnosed with prostate cancer. These biomarkers [technically looking at hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF) and prostate specific antigen (PSA)] are good prognostic indicators of prostate cancer progression.
The men involved in the study were given 4 green tea capsules for an average of 34 days prior to surgery. The 4 capsules provided the equivalent of around 12 cups of normally brewed green tea. Results showed that there was a significant reduction in blood serum levels of the biological-markers of prostate cancer after treatment with the green tea capsules. Some of the patients had reductions in the biomarker levels of more than 30%. The supplements had no effect on liver function, which was used as a measure of toxicity.
The supplement used contained 1.3g tea polyphenols, bioactive plant nutrients, that are found naturally in green tea: 800 mg of epigallocatechin-3-gallate (EGCG) and lesser amounts of epicatechin, epigallocatechin, and epicatechin-3-gallate. Green tea supplements often have these polyphenols listed as active ‘ingredients’.
In a press release(2) one of the authors commented: “These studies are just the beginning and a lot of work remains to be done, however, we think that the use of tea polyphenols alone or in combination with other compounds currently used for cancer therapy should be explored as an approach to prevent cancer progression and recurrence“.
In the same press release(2) William G. Nelson, V., M.D., Ph.D., professor of oncology, urology and pharmacology at the Johns Hopkins Kimmel Cancer Center, said that he believed the reduced blood serum biomarkers of prostate cancer may be attributable to some sort of benefit relating to green tea components “Unfortunately, this trial was not a randomized trial, which would have been needed to be more sure that the observed changes were truly attributable to the green tea components and not to some other lifestyle change (better diet, taking vitamins, etc.) men undertook in preparation for surgery,”. However, “this trial is provocative enough to consider a more substantial randomized trial.”
The researchers of this study are currently conducting a comparable trial among patients with breast cancer.
For general information about nutrition and prostate health please read my previous blog posts on the subject (Prostate health Part I and II). For more information on prostate cancer please visit the Prostate Cancer Care website.
The World Cancer Research Fund (WCRF) estimate that lifestyle factors such as being overweight, eating an unhealthy diet and being inactive are responsible for about a third of all cancers in developed countries (3). Please visit the WCRF website for information related to diet and cancer prevention.
1. McLarty J et al. 2009. Tea Polyphenols Decrease Serum Levels of Prostate-Specific Antigen, Hepatocyte Growth Factor, and Vascular Endothelial Growth Factor in Prostate Cancer Patients and Inhibit Production of Hepatocyte Growth Factor and Vascular Endothelial Growth Factor In vitro. Cancer Prevention Research, 10.1158/1940-6207.CAPR-08-0167. Published online June 19
2.Sciencedaily.com press release. American Association for Cancer Research (2009, June 22). Green Tea May Slow Prostate Cancer Progression. ScienceDaily. Retrieved June 23, 2009, from http://www.sciencedaily.com¬ /releases/2009/06/090619112329.htm
(3) WCRF/AICR. 2009. Policy and action for cancer prevention. Food, nutrition and physical activity: a global perspective. Washington DC: AICR, 2009.
Written by Ani Kowal
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