Berries contain polyphenols. There are two polyphenols especially important to cancer studies in that these two compounds work together. They’re anthocyanins, a flavonoid that gives berries their awesome color, and ellagitannins, the source of ellagic acid.
We’re aware berries are high in manganese, fiber, vitamin C and antioxidants—which prevents cell damage that precedes cancer. What’s new is that berries are now found to affect the genes associated with inflammation and cancer growth.
Dr. Gary Stoner is a professor at Medical College of Wisconsin. For more than 20 years, he’s been studying berries and their potential to prevent cancer. In one study, he found a diet of black raspberries or strawberries freeze-dried and ground into a powder could inhibit esophageal cancer in rats 30-70 percent, and colon cancer up to 80 percent.
In another study, Dr. Gary Stoner worked with patients diagnosed with an inherited condition that increases their risk for colon cancer. Patients were given black raspberry powder mixed with water to drink, and in the form of rectal suppositories for nine months. This study found a thirty-six percent regression of rectal polyps in these patients. (This just begs me to add: Consult your doctor and don’t try this at home.)
Blueberries, blackberries and the effects on estrogen-positive breast tumors were the focus of studies done by Dr. Harini Aiyer, a post doctoral research fellow at Lombardi Cancer Center, Georgetown University School of Medicine.
A six month diet of black raspberries reduced breast tumor volume in rats seventy percent. Blueberries reduced tumor volume by sixty percent during a six-month period.
In Dr. Aiyer’s cell culture studies, she found that adding ellagic acid to estrogen-positive cells treated with tamoxifen made the cells less likely to become resistant to the effects of the drug. This makes it seem like ellagic acid (the berries used) act like anti-estrogen. Many more studies are needed for this.
A few things to keep in mind: The studies look promising. You’re supposed to eat plenty of fruit anyway. Fresh, unsweetened frozen or canned berries are all good choices. Don’t forego other healthy food groups for a diet of berries only, and you may want to mix berry types to get that cross-training feeling.