(HealthDay News) -- Blueberries, already touted as a super food because they may protect against memory loss and heart disease, could help stop the development of colon cancer, a new study finds.

The study showed that a natural compound called pterostilbene -- found in blueberries and other fruits -- helped prevent pre-cancerous colon lesions in rats.

"Pterostilbene is an antioxidant and an anti-inflammatory agent that is mostly found in blueberries and blackberries," said study leader Bandaru Reddy, a research professor at Rutgers University's Susan Lehman Cullman Laboratory for Cancer Research, in Piscataway, N.J. "We tested it using a rat model that is very similar to the human situation. Several other compounds tested using this model in the past are already in human trials."

The study was conducted by researchers at Rutgers and the U.S. Department of Agriculture and was funded by the U.S. National Cancer Institute. The findings were presented Sunday at the annual meeting of the American Chemical Society (ACS) in Chicago.

Colon cancer is one of the major cancers in Western countries, and this study is one of the first to show pterostilbene's potential to fight it, Reddy said.

For the pilot study, the researchers gave 18 rats a compound called azoxymethane, a chemical that induces colon cancer.

Half of the rats were then fed a balanced diet, while the other half were given the same diet plus the compound pterostilbene (at a level of 40 parts per million).

After eight weeks, the rats who were fed pterostilbene had 57 percent fewer pre-cancerous lesions in their colon (called preneoplastic lesions) compared to the other group. Ingesting pterostilbene also reduced colonic cell proliferation and inhibited the expression of certain genes involved in inflammation -- both of these are considered to be risk factors for colon cancer, the study authors said.

The next step is to further test pterostilbene in animals to see if it can prevent tumors. Only then will human trials be possible, Reddy said.

Jon A. Story, a professor of foods and nutrition at Purdue University in West Lafayette, Ind., called the findings interesting but preliminary.

"This model for colon cancer is a good place to start," he said. "But the fact remains that chemical induction of cellular changes may not tell us much concerning the development of human tumors. More models are needed to get a better idea of this relationship."

Still, it can't hurt to add berries to your diet, added James Joseph, chief of the neuroscience laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston.

"Eat berries regardless of this study," he said. "There's lots of other data out there on the health benefits of berries. In general, be sure to eat 10 servings of fruits and vegetables a day, especially colorful ones that are high in antioxidants. And iceberg lettuce doesn't count."

Other papers scheduled to be presented at the ACS meeting also demonstrated fruits' potential anticancer benefits.

One study, by researchers at the University of Alabama in Birmingham, found that chemicals from grape-seed extract might prevent sunlight-induced skin cancer in mice when used as a dietary supplement.

Another study from Ohio State University found that rodents whose diets were supplemented with black raspberries had up to an 80 percent reduction in colon tumors and a 60 percent reduction in tumors of the esophagus.

And researchers in Germany were to report on a study that found drinking two to three glasses of cloudy (or unfiltered) apple juice a day may curb colon cancer in mice.

Story stressed that people should not rely on any one food to prevent colon cancer.

"Recommendations concerning colon cancer prevention need to include all parts of the diet, not a single component," he said.

More information

There's more on antioxidants at the U.S. National Cancer Institute.

SOURCES: Bandaru Reddy, Ph.D., research professor, department of chemical biology, Susan Lehman Cullman Laboratory for Cancer Research, Rutgers University, Piscataway, N.J.; Jon A. Story, Ph.D., professor, foods and nutrition, Purdue University, West Lfayette, Ind.; James Joseph, Ph.D., chief, the neuroscience laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston; March 25, 2007, presentations, annual meeting, American Chemical Society, Chicago
Last Updated: February 2008
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