Blueberries compound may offer protection against colon cancer

A study recent shows that a compound called pterostilbene found abundantly in blueberries offered protection against colon cancer. The study, presented on Monday by researchers at the U.S. Department of Agriculture and Rutgers University, showed that the compound is a powerful antioxidant and has the potential to be developed into a pill as well.

"This study underscores the need to include more berries in the diet, especially blueberries," says study leader Bandaru Reddy, Ph.D., a professor in the Department of Chemical Biology at Rutgers in Piscataway, N.J. Although the blueberry compound won't cure colon cancer, it represents a potential new and attractive strategy for preventing the disease naturally, says Reddy, a leading expert on nutritional factors that influence colon cancer development.

At the end of the study, the nine animals that received pterostilbene supplement had 57-percent fewer pre-cancerous growths in the colon compared with the animals that were fed a balanced diet only. Pterostilbene also reduced colonic cell proliferation and inhibited certain genes involved in inflammation, both of which are considered colon cancer risk factors, the researchers say.

Although researchers still do not know the exact cause of colon cancer, the disease has been linked to a high intake of saturated fats and calories, particularly in Western diets. Pterostilbene may be able to reverse this process, possibly by lowering lipids, Reddy says. 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 (see AGFD 038 reference below). More studies on the mechanism of action of pterostilbene are needed, the researchers note.

Reddy recently demonstrated that certain COX-2 inhibitors, anti-inflammatory drugs that are used for pain and arthritis, were capable of preventing colon cancer in animals. But 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 drugs could allow them to be used in lower doses, reducing their risk of adverse side effects, Reddy says. More studies are needed to determine the compound's efficacy and potential for toxicity, he notes.

Pterostilbene is an antioxidant that is similar to resveratrol, an antioxidant identified in grapes and red wine that also is recognized for its anticancer properties. It is believed that the compound also has anti-diabetic properties, but so far very little has been studied on this issue. Additionally, it is also touted as a potent anti-fungal. Pterostilbene also is found in grapes, but it is more abundant in blueberries, the researchers say.

Berries can be part of a healthy diet. But it's too soon to count on berries to prevent colon cancer.