Blueberries may help lower your risk for heart disease, according to a study published in "The Journal of Nutrition" in September 2010. This is most likely due to the high amounts of a type of antioxidant called polyphenols that they contain. Blueberries also provide a number of essential nutrients, including fiber, manganese and vitamins C and K.

A 1-cup serving of raw blueberries has 84 calories, 0.5 gram of fat, 1.1 grams of protein and 21.4 grams of carbohydrates, including 3.6 grams of fiber. This is 14 percent of the daily value for fiber, based on a 2,000-calorie diet. Getting the recommended amount of fiber in your diet may help lower your risk for certain types of cancer, constipation, high cholesterol and heart disease.

Each 1-cup serving of blueberries also provides 24 percent of the DV for vitamin C, 36 percent of the DV for vitamin K and 25 percent of the DV for manganese. You need vitamin K for blood clotting and to keep your bones strong. Both manganese and vitamin C aid in wound healing and also act as antioxidants to help protect your cells from damage by free radicals, which are highly reactive chemicals found in the body and environment that can harm cells.