Some say that eating tomatoes may reduce the risk of prostate cancer. Is it true? Hard to say since, as you’ll learn here, nothing is black and white, especially when it comes to what you eat and how it affects your health.
I begin my blog with an exploration of the scientific debate over the tomato and the antioxidant (potential cancer-fighting substance), lycopene, found in high concentration in tomatoes and tomato products. Next time around, I’ll explain how lycopene works in your body, and list more details about food sources.
The Studies
During the last several years, much has been researched and written about the powerful antioxidant lycopene and how lycopene and/or tomato products may reduce the risk of prostate cancer as well as slow the growth of the cancer cells themselves. Most recently, Dr. Neil Fleshner of the University of Toronto reported in February on the potential positive impact of lycopene on prostate cancer at the three-day Prostate Cancer Symposium, sponsored by the American Society of Clinical Oncologists.
Lycopene began to achieve its notoriety in the mid 1990s, when a large study conducted by the Harvard Medical School and the Harvard School of Public Health concluded that frequent consumption of tomato products was associated with a lower risk of prostate cancer. A follow-up evaluation suggested that 10 or more servings of tomato sauce a week resulted in even a greater reduction in prostate cancer risk, and a 35% decreased risk in the incident of advanced prostate cancer (Journal of the National Cancer Institute, Vol. 94, No. 5, 391-398, March 6, 2002). A more recent article in the November 2005 issue of the Journal of Clinical Oncology, “The Role of Diet in Prostate Cancer Development and Progression”, makes reference to several studies where it was shown that tomato sauce reduced the risk of prostate cancer and slowed the progression of diagnosed prostate cancer. Numerous studies are currently underway with lycopene.
To the contrary, other studies, including one involving the National Cancer Institute (NCI), Yale University School of Medicine, and New York University, have not been so supportive of the theory of cancer-fighting properties of tomato-based foods. The NCI study, based on a general risk factor and what-foods-do-you-eat questionnaire, did not support the hypothesis that greater lycopene/ tomato product consumption protects against prostate cancer. But the researchers did conclude that lycopene/tomato products might offer some protection for those men with a family history of prostate cancer. And you need to keep in mind, that these types of questionnaires, which rely on people’s memories, can be flawed. (“A Prospective Study of Lycopene and Tomato Product Intake and Risk of prostate Cancer”, Cancer Epidemiology Biomarkers & Prevention, January 2006)
Food and Drug Administration (FDA) and Health Claims
To confuse the issues even more, the FDA in November 2005 issued letters in response to two petitioners who were asking for approval of their products’ prostate cancer-fighting health claims. One was the H.J. Heinz Company, making claims for lycopene and tomato-based products (it’s ketchup sales rose 4%), and the second was American Longevity, Inc., a maker of a lycopene dietary supplement. The FDA letter to H.J. Heinz makes for interesting reading, and you can find it at: http://www.cfsan.fda.gov/~dms/qhclyco2.html.
After reviewing all the pertinent studies, articles, and other relevant materials, the FDA concluded the following:
“Very limited and preliminary scientific research suggests that eating one-half to one cup of tomatoes and/or tomato sauce a week may reduce the risk of prostate cancer. FDA concludes that there is little scientific evidence supporting this claim.”
Many have disagreed with this assessment—time will tell. The FDA did not consider the impact of consuming significantly more servings of tomato products per week.
Where does all this leave us? Although I think the evidence is mounting for the anti-prostate cancer benefits derived from tomatoes, more research needs to be done. But one thing is for sure: drinking a glass of tomato juice, eating a tomato, or digging into a plate of pasta topped with tomato sauce is not going to be harmful to our health.
(To incorporate the lycopene-powerhouse sun-dried tomatoes into your everyday eating, check out the Sun-Dried Tomato Dip recipe on the home page and recipes page.)
Next Blog: How does lycopene work in the body, other benefits, and what foods are good sources of lycopene?