Researchers found evidence in rats that black raspberries may both prevent the onset of esophageal cancer as well as inhibit precancerous growth already underway.
"Black raspberries are loaded with nutrients and phytochemicals that may prevent the development of cancer," said Gary Stoner, a study co-author and a professor of public health at Ohio State University.
Stoner, who has also found similar anti-carcinogenic effects with strawberries, said the study results suggest that a daily diet of about 1.4 to 2 cups of fresh berries may be ideal for staving off certain types of cancer.
"Although this level is larger than a standard serving size of fruit, it is behaviorally possible," he said. "The National Cancer Institute recommends that every American eat at least four to six helpings of fruit and vegetables each day. We suggest that one of these helpings be berries of some sort."
The research appears in the journal Cancer Research.
Esophageal cancer is the sixth-leading cause of cancer-related deaths worldwide. The outlook is bleak for those diagnosed with the disease - five-year survival rates range from 8 to 12 percent.