Researchers at the USDA Human Nutrition Center (HNRCA) have found that blueberries rank #1 in antioxidant activity when compared to 40 other fresh fruits and vegetables. Antioxidants help neutralize harmful by-products of metabolism called "free radicals" that can lead to cancer and other age related diseases. Anthocyanin -- the pigment that makes the blueberries blue -- is thought to be responsible for this major health benefit. In another USDA Human Nutrition Center (HNRCA) lab, neuroscientists discovered that feeding blueberries to laboratory rats slowed age-related loss in their mental capacity, a finding that has important implications for humans. Again, the high antioxidant activity of blueberries probably played a role. A one cup serving of blueberries contains 16% DV of fiber. Blueberries are a source of Vitamins A and C, potassium and folate. Blueberries are very low in fat and sodium.