Dr. Gary Stoner, a researcher in chemoprevention, is currently conducting several trials evaluating black raspberry supplements as a way to prevent or slow the growth of colon and other cancers. He and other scientists at The Ohio State University Comprehensive Cancer Center have been researching the anticancer properties of berries for nearly 20 years.

Specifically, they have studied the ability of freeze-dried berries (black raspberries, strawberries and blackberries) to inhibit cancer in the esophagus, colon and mouth.

Berries are packed with cancer preventives including vitamins A, C, and E; calcium and selenium; ß-carotene and lutein. Many phenolic compounds which have high anti-oxidant potential.

The most abundant phenols are the anthocyanins (from Greek anthos = flower + kyanos = blue) which give berries their color. In general, dark, purple berries have higher contents of anthocyanins and anti-oxidant potential than red or lighter berries.

Adding powdered berries at 5 and 10% of the diet of animals reduces their risk for development of cancer in the oral cavity, esophagus and colon by 45-80%. Berries function to reduce the amount of genetic (DNA) damage produced in these tissues by chemical carcinogens, including carcinogens in tobacco smoke and in the diet. They also reduce the growth rate of precancerous cells, in part, by reducing the expression of genes associated with cell growth.

Berries also inhibit the expression of other genes associated with cancer development including genes involved in inflammatory processes and in the formation of new blood vessels (angiogenesis).

In a preliminary trial in humans, berries were found to be well tolerated at doses similar to those used in animals. They reduced cellular damage caused by oxidative radicals which is consistent with their anti-oxidant potential.

In view of these results, several human clinical trials are ongoing to determine the ability of freeze-dried berries to inhibit the development of precancerous lesions in the oral cavity, esophagus and colon of humans. Preliminary results suggest that berries influence the expression of many of the same genes in humans as they do in animals. An apparent advantage of this “food-based” approach to disease prevention is the relative absence of toxicity associated with the long-term consumption of berries by humans.