“This potent little fruit can help prevent a range of diseases from cancer to heart disease,” says Ryan Andrews, the director of research at Precision Nutrition, in Toronto, Canada. Think of blueberries as anti-rust for your gray matter, too. Besides being rich in fiber and vitamins A and C, they’re also packed with antioxidants-only açai, an Amazonian berry, contains more-that neutralize the free radicals that cause neuronal misfires. Eat a cup a day, and opt for wild blueberries whenever possible, as they contain 26 percent more antioxidants than cultivated varieties.