Did mom tell you to eat your fruits and vegetables? She was right. We have been counseled for years (albeit, at times under duress) that eating more fruits and vegetables is not only a healthy lifestyle move, it can also help stay off chronic diseases. So it comes as no great shock that researchers have found new evidence to back up mom.
Eating fruits, such as pomegranates, that contain anti-aromatase phyochemicals reduce the incidence of hormone-dependent breast cancer, according to results of a study published in the January 2010 issue of Cancer Prevention Reserch, a journal of the American Assocation for Cancer Research.
What makes pomegranates a super fruit? They are enriched with a series of compounds known as ellagitannins, a phytochemical, shown to inhibit the proliferation of human cancer cells and to cause cancer cell apoptosis -- a kind of nuclear level “cell suicide” process.
"Phytochemicals suppress estrogen production that prevents the proliferation of breast cancer cells and the growth of estrogen-responsive tumors," said principal investigator Shiuan Chen, Ph.D., director of the Division of Tumor Cell Biology and co-leader of the Breast Cancer Research Program at City of Hope in Duarte, Calif.
Previous research has shown that pomegranate juice is high in antioxidants, which are generally attributed to the fruit's high polyphenol content. Ellagic acid found in pomegranates inhibits aromatase, an enzyme that converts the steroid hormone, androgen, to estrogen. Since aromatase plays a key role in breast carcinogenesis, Dr. Chen, along with Lynn Adams, Ph.D., a research fellow at Beckman Research Institute of City of Hope, and colleagues, evaluated whether phytochemicals in pomegranates can suppress aromatase and ultimately inhibit breast cancer cell growth.
After researching a panel of ten ellagitannin-derived compounds in pomegranates, the investigators found that those compounds have the potential to prevent estrogen-responsive breast cancers. Specifically, Urolithin B, which is a metabolite produced from ellagic acid and related compounds, was found to significantly inhibited cell growth.
Similar effects have been found in grapes, almonds and raspberries, however Dr. Chen was surprised by the pomegranate research findings since the phytochemicals in other fruits are very different from those in the pomegranate.
Gary Stoner, Ph.D., a professor in the Department of Internal Medicine at Ohio State University, said additional studies will be needed to confirm the chemopreventive action of Urolithin B against hormone-dependent breast cancer, but believes the findings are promising enough to suggest more animal and human experiments with pomegranates are warranted.
"This is an in-vitro study in which relatively high levels of ellagitannin compounds were required to demonstrate an anti-proliferative effect on cultured breast cancer cells," said Stoner, who is not associated with this study. “It's not clear that these levels could be achieved in animals or in humans because these ellagitannins are not well absorbed into blood when provided in the diet.”
Powel Brown, M.D., Ph.D., medical oncologist and chairman of the Clinical Cancer Prevention Department at the University of Texas M. D. Anderson Cancer Center, agreed with Stoner's sentiments, saying he is “intrigued” by the results. He recommended that future studies focus on testing pomegranate juice for its effect on estrogen levels, menopausal symptoms, breast density or even as a cancer preventive agent.
“More research on the individual components and the combination of chemicals is needed to understand the potential risks and benefits of using pomegranate juice or isolated compounds for a health benefit or for cancer prevention,” Brown said. “This study does suggest that studies of the ellagitannins from pomegranates should be continued.”
In the meantime, Dr. Stoner said people “might consider consuming more pomegranates to protect against breast cancer development and perhaps in other tissues and organs.”
Lynette Summerill, is an award-winning journalist who lives in Scottsdale, Arizona. In addition to writing about cancer-related issues, she writes a blog, Nonsmoking Nation, which follows global tobacco news and events.