New research shows that a variety of other types of berries – including more readily available and affordable blueberries, strawberries and red raspberries – along with more exotic and expensive varieties like noni, acaí (pronounced ah-sye-EE) and wolfberries – may prevent cancer about as well as previously studied black raspberries.
In the first-ever study comparing the cancer preventive properties of berries, researchers at The Ohio State University Comprehensive Cancer Center – Arthur G. James Cancer Hospital and Richard J. Solove Research Institute (OSUCCC-James), tested seven berry types and found that all seven were about equally effective in preventing the development of esophageal cancer in rodents.
The preliminary findings are published in the current issue of the journal Pharmaceutical Research.
Dr. Gary Stoner, an OSUCCC-James researcher, has spent much of his career collaborating with other scientists to prove the potency of black raspberries in preventing cancer. Researchers have shown that anthocyanins, which are responsible for the dark purple-black color of the berries, also share the credit for much of their cancer preventive potential. Other chemopreventive compounds in black raspberries include ellagitannins and other phenols.
“Over the years, I’ve received numerous queries from the public regarding the cancer preventive potential of berries other than black raspberries,” Stoner says. “People are concerned that black raspberries are either not available at all or only one or two months per year, and they want to know if they can use other berry types.”
Stoner and colleagues decided to study other berries to determine if they might be effective. Because the other berry types generally contain lower levels of anthocyanins and ellagitannins than black raspberries, researchers initially thought they would be considerably less active than black raspberries in preventing carcinogen-induced esophagus cancer in rats.
After turning the berries into freeze-dried powder and mixing them into the rodents’ diets, Stoner was surprised by the findings.
“Our results indicated that all seven berry types were effective, irrespective of their contents of anthocyanins and ellagitannins. Apparently, each type of berry contains unique compounds that are responsible for their cancer preventive effects,” says Stoner.
One advantage of extending these studies to other berry types is that blueberries, strawberries and red raspberries are more readily available to the public throughout the year than black raspberries.
Acaí berries are native to Central and South America, noni berries are native to Hawaii, Southeast Asia and the tropics, and wolfberries, also known as goji berries, are native to China, Asia and part of Europe. Some of these berries have been advertised as having high levels of antioxidants and superior potential for disease prevention.
“In addition, with respect to cancer prevention, it’s not clear that the ‘exotic’ berry types are any more effective than the less expensive blueberries, strawberries and red raspberries,” adds Stoner.
This is good news for anyone who wants to add lower-cost, higher-impact berries to their diets.
“Everyone should be consuming more of all berry types, although it’s difficult to know how many berries people must consume to reap the preventive benefits,” says Stoner. “There’s good evidence that berries are protective against cardiovascular disease, too.
Researchers plan to do more studies to determine if berries other than black raspberries are also effective in other organ sites, and to determine which berries can offer the most cancer protection with the least amount of consumption.
“We tested all berry types at only one dose level, so we might see differences in their effectiveness if we compare all of them at a lower dose,” Stoner says.
The study also determined that berries influence the levels of inflammatory cytokines in the serum of carcinogen-treated rats. All berry types were shown to reduce the levels of the serum cytokines, interleukin 5 (IL-5) and GRO/KC, the rat homologue for human interleukin-8 (IL-8), and this was associated with increased serum antioxidant capacity, Stoner said. These serum levels may serve as biomarkers of the chemopreventive effects of berries.
Other Ohio State researchers involved in the study are Li-Shu Wang, Claire Seguin, Claudio Rocha, Kristen Stoner, Steven Chiu and A. Douglas Kinghorn.
The berries used in the study were provided by Dale Stokes of the Stokes Raspberry Farm in Wilmington, Ohio, (black and red raspberries); Erin Theony and the Washington State Raspberry Commission (red raspberries); Watershed Foods, Gridley, Ill., (blueberries); Driscoll Farms of Watsonville, Calif., (strawberries) and Dr. William J. Keller of Nature’s Sunshine, Inc., Spanish Fork, Utah, (noni, acaí and wolfberries).
This study was supported by the National Cancer Institute and the United States Department of Agriculture through the Ohio Agricultural Research and Development Center.
The Ohio State University Comprehensive Cancer Center – Arthur G. James Cancer Hospital and Richard J. Solove Research Institute (cancer.osu.edu) is one of only 40 Comprehensive Cancer Centers in the United States designated by the National Cancer Institute. Ranked by U.S. News & World Report among the top 20 cancer hospitals in the nation, The James is the 180-bed adult patient-care component of the cancer program at The Ohio State University. The OSUCCC-James is one of only seven funded programs in the country approved by the NCI to conduct both Phase I and Phase II clinical trials.
Medical Center Communications