Raspberries are bursting with nutrients and flavor, yet they are very low in calories. Clinical studies suggest that daily consumption of red raspberries can help prevent pancreatic cancer, most probably due to their high concentration of ellagic acid. While ellagic acid is found in a number of foods, red raspberries are by far the best dietary source of this miraculous cancer-fighting substance (1,500 mcg per gram of dry weight fruit extract). Ellagic acid is a proven anti-carcinogen, anti-mutagen, and an inhibitor of cancer. It may also be able to cause apoptosis (cell death) in cancer cells. Furthermore, the ellagic acid found in red raspberries retains its potency through heating and freezing. So, regardless of whether you eat your raspberries fresh, frozen or heated, you will reap their cancer-fighting benefits.