Blueberry Compound May Help Prevent Colon Cancer

Department of Agriculture (USDA; Washington, DC, USA).

Colon cancer is considered the second leading cause of cancer death in the United States. While recent studies have identified a growing number of antioxidants in fruits, vegetables, and whole grains that show potential for fighting colon cancer, the investigators believe that, this is the first study to demonstrate the cancer-fighting potential of pterostilbene against the disease. Their findings were described at the annual national meeting of the American Chemical Society, held in March 2007 in Chicago, IL, USA.

"This study underscores the need to include more berries in the diet, especially blueberries,” stated study leader Bandaru Reddy, Ph.D., a professor in the department of chemical biology at Rutgers. Although the blueberry compound will not cure colon cancer, it represents a potential new and attractive strategy for preventing the disease naturally, reported Dr. Reddy, a leading expert on nutritional factors that influence colon cancer development.

Along with scientists Drs. Nanjoo Suh, also from Rutgers, and Agnes Rimando of the USDA's Agricultural Research Service (ARS), Dr. Reddy and his associates conducted a small pilot study to determine the effect of pterostilbene on colon cancer. The study included 18 rats that were given a compound (azoxymethane) to induce colon cancer in a manner similar to human colon cancer development. Nine of the animals were then given a balanced daily diet, whereas the other nine were given the same diet supplemented with pterostilbene (at a level of 40 parts per million).

At the end of an eight-week study period, the rats that were fed pterostilbene showed 57% fewer pre-cancerous lesions in their colon in comparison to the control group. Pterostilbene also reduced colonic cell proliferation and suppressed certain genes involved in inflammation, both of which are considered colon cancer risk factors, according to the investigators.

Although researchers still do not know the precise cause of colon cancer, the disease has been link associated with a high intake of saturated fats and calories, particularly in Western diets. Pterostilbene may be able to reverse this process, possibly by lowering lipids, according to Dr. Reddy. He cites a recent study by co-author Agnes Rimando, a research chemist at the USDA-ARS, who demonstrated in cell and animal studies that pterostilbene is capable of lowering cholesterol levels. In a related paper also being presented at the ACS national meeting, Rimando demonstrated that blueberries, particularly their skins, can lower cholesterol when fed to animals. More studies on the process of action of pterostilbene are needed, the researchers noted.

Dr. Reddy recently demonstrated that specific COX-2 inhibitors, anti-inflammatory drugs that are used for pain and arthritis, were capable of preventing colon cancer in animal studies. However, studies by others have shown that COX-2 inhibitors also can increase the risk of heart attacks and strokes when used in high doses. Combining pterostilbene with these COX-2 agents could allow them to be used in lower doses, reducing their risk of adverse side effects, according to Dr. Reddy. More studies are needed to determine the compound's effectiveness and potential for toxicity, he noted.

Pterostilbene is an antioxidant that is similar to resveratrol, an antioxidant identified in grapes and red wine that is recognized for its anticancer properties. Pterostilbene also is found in grapes, but it is more plentiful in blueberries, according to the researchers.

In studies by other researchers, blueberries also have shown potential for protecting against memory loss and heart disease. Generally, health experts for the prevention of colon cancer recommend a diet rich in fruits, vegetables, and grain.


Related Links:
Rutgers University
U.S. Department of Agriculture