In the current study, Stoner and his colleagues tested the effects of ellagic acid - a plant nutrient shown to have protective effects against esophageal cancer. Berries are rich in ellagic acid. But the researchers found that ellagic acid alone could not account for the fruit's ability to inhibit cancer. "One or more additional berry components are undoubtedly contributing to the fruit's anti-cancer effects," Stoner said.
He chose black raspberries for this study because previous studies had shown that ellagic acid inhibited carcinogen-induced esophageal and colon cancer in animals. He and his colleagues then tested a series of fruits for their ellagic acid content, finding that berries contained the highest amount.
"We then decided to take a food-based approach to cancer prevention and began testing the berries' ability to inhibit chemically-induced esophageal and colon cancer," Stoner said. "Sure enough, we found that freeze-dried berries were highly protective in the esophagus and colon. But we also found that they were ineffective in protecting against lung cancer.
"The protective compounds in berries may not be absorbed into
the blood stream and delivered to the lungs in high enough
amounts to be protective.
Contact: Gary Stoner
Ohio State University