Ellagic acid is a polyphenolic antioxidant found in a variety of plant foods, including pomegranates, raspberries, blackberries, strawberries, cranberries, walnuts and pecans. The health benefits of many plants, such as green tea, are thought to be due to their content of polyphenols. Most studies involving ellagic acid have employed pomegranate fruit juice, as it is a particularly good source of this particular polyphenol. Ellagic acid's potent antioxidant and antitumor activities have caught the attention of scientists interested in preventing and treating prostate cancer.
Prostate Cancer Overview
According to the National Academy of Sciences, prostate cancer is the most common invasive cancer and the second leading cause of cancer deaths among American males. Localized prostate cancer is curable with surgery or radiation therapy, but disease that has spread beyond the prostate is associated with a poor prognosis. Therefore, prevention of prostate cancer through dietary and other lifestyle manipulations is an important goal.
Animal Studies
Much of the research surrounding ellagic acid and prostate cancer has been conducted in animal models or in tissue cultures of human prostate cancer cells. A 2005 "Carcinogenesis" study demonstrated that ellagic acid inhibited the growth of tumors by interfering with the growth of new blood vessels in cultured cells. Another 2005 study in "Journal of Agricultural and Food Chemistry" showed that ellagic acid is an effective antagonist of estrogen receptors, which holds important implications for the management of prostate and other hormone-driven cancers. Still other studies reveal ellagic acid's ability to prevent the growth of implanted human prostate cancer cells in mice.
Human Studies
Ellagic acid has not been shown to prevent or cure prostate cancer. However, in 2005 Italian scientists demonstrated that ellagic acid reduces the toxic effects of chemotherapy in men with metastatic, treatment-resistant prostate cancer, and a 2006 study in "Clinical Cancer Research" showed that the consumption of ellagic acid slowed the progression of prostate cancer following initial treatment with surgery or radiation therapy. Long-term human trials evaluating ellagic acid's ability to prevent prostate cancer have not been conducted.
Considerations and Recommendations
Ellagic acid may slow the progression of prostate cancer in men who have already been treated with surgery or radiation. Ellagic acid may also reduce the toxic effects of chemotherapy in men with prostate cancer. Some studies suggest that the consumption of ellagic acid-rich foods, such as pomegranates, may prevent prostate cancer, but there is insufficient evidence to support this claim. Human trials evaluating ellagic acid's effects on prostate cancer have used preparations providing 180 to 570 mg of ellagic acid daily. If you think ellagic acid could be beneficial for you, talk to your doctor.
References
- "Proceedings of the National Academy of Sciences of the United States"; Pomegranate Fruit Juice for Chemoprevention and Chemotherapy of Prostate Cancer; A. Malik, et al; October 2005
- "Carcinogenesis"; Combined Inhibition of PDGF and VEGF by Ellagic Acid, a Dietary-Derived Phenolic Compound; L. Labrecque, et al.; January 2005
- "Journal of Agricultural and Food Chemistry"; Evaluation of Estrogenic/Antiestrogenic Activity of Ellagic Acid via the Estrogen Receptor Subtypes ERα and ERß; Z. Papoutsi, et al.; September 2005
- "European Urology"; Support Ellagic Acid Therapy in Patients with Hormone Refractory Prostate Cancer (HRPC) on Standard Chemotherapy Using Vinorelbine and Estramustine Phosphate; M. Falsaperla, et al.; April 2005
- "Clinical Cancer Research"; Phase II Study of Pomegranate Juice for Men with Rising Prostate-Specific Antigen Following Surgery or Radiation for Prostate Cancer; A.J. Pantuck, et al.; July 2006
- "Cell Cycle"; Prostate Cancer Prevention through Pomegranate Fruit; A. Malik, H. Mukhtar; February 2006
