Blueberries are known to have one of the highest antioxidant capacities among all fruits and vegetables. These high levels of anti-oxidants combined with high levels of vitamin K, vitamin C, manganese and fibre are what make blueberries a superfood.
“One of the few naturally blue-hued foods humans eat, blueberries are packed with antioxidant power, which comes from high levels of anthocyanins, a type of flavonoid. They also contain significant amounts of micronutrients and fibre.” 
New studies are emerging all the time showing the numerous health benefits of eating blueberries regularly – in particular, fresh, raw blueberries.
1. Whole Body Anti-Oxidant Support
Given the wide variety of antioxidant nutrients present in blueberries, it is not surprising to find research studies showing improved antioxidant defenses in body systems that need special protection from oxidative stress, like the cardiovascular system. But what is surprising about the blueberry research is its whole body relevance.
“It is not only the cardiovascular system that has been shown to have strengthened antioxidant status following consumption of blueberries. It is virtually every body system studied to date!”
For example, there is new evidence that damage to muscles following overly taxing exercise can be reduced through consumption of blueberries. There is also evidence that protection of the nervous system from oxidative stress can be accomplished by regular consumption of blueberries. 
2. Cardiovascular Support
Blueberry support of antioxidant defenses has been especially well documented with respect to the cardiovascular system. It’s the many different pathways for cardio support that are so striking in the blueberry research. In repeated studies of blood composition, blueberry intake (usually in the amount of 1-2 cups per day and over the course of 1-3 months)
“has been shown to improve blood fat balances, including reduction in total cholesterol, raising of HDL cholesterol, and lowering of triglycerides.”
At the same time, blueberry intake has been shown to help protect the blood components (like LDL cholesterol) from oxygen damage that could lead to eventual clogging of the blood vessels. Protection has also been shown for the cells lining the blood vessel walls. Connected with this antioxidant protection of blood vessel structures and blood fats is an improved overall antioxidant capacity in the blood itself. 
3. Anti-Cancer Benefits
An increasing percentage of the blueberry research is being focused on anti-cancer benefits. Types of cancer already studied with respect to blueberry intake include breast cancer, colon cancer, esophageal cancer, and cancers of the small intestine. We look forward to the results of large-scale human studies on the potential ability of blueberry intake to lower risk of these cancer types. 
4. Blood Sugar Benefits
Research on blood sugar balance and blueberry intake has been conducted on individuals who have been diagnosed with type 2 diabetes, metabolic syndrome, or insulin resistance, and the results of this research have been consistent. They have shown that
“blueberries (along with other berries) have a favorable impact on blood sugar regulation in persons already diagnosed with blood sugar problems.” 
5. Improved Memory and Brain Function
Compounds in blueberries known as flavonoids may improve memory, learning and general cognitive function—and could slow age-related decline in mental function.
A recent study has shown that eating blueberries can help delay cognitive decline, as seen in diseases such as Alzheimer’s, by as much as two-and-a-half years.
“… the findings are ‘exciting’ because they suggest that a simple dietary modification [eating blueberries] may provide memory benefits for older adults.”
6. Eye Health
Blueberries have also been shown to have a positive impact on eye health. In preliminary studies on laboratory animals, the anthocyanins in blueberry protected the retina from unwanted oxygen damage. Interestingly, they have also been determined to help protect the retina from damage from sunlight. 
7. Lower Risk of Heart Disease and Diabetes
A 2009 study shows that eating regular servings of raw blueberries can lower abdominal fat and also lower the risk of heart disease and diabetes.
“Researchers say the results suggest that antioxidant-rich blueberries may change how the body stores and processes glucose or sugar for energy, thereby reducing the risk of both heart disease and diabetes.”
 George Mateljan Foundation for the World’s Healthiest Foods: Blueberries
 Scientific American: Your Brain on Blueberries: Enhance Memory with the Right Foods
 Wikipedia: Blueberry
 Chicago Tribune: The Benefits of Berries