Research indicates that a diet rich in blueberries is also rich in antioxidants. The animal study tested diets of blueberry, strawberry, and spinach extracts. Those rats given the blueberries were given what they needed to surpass the other rats. It is believed that the antioxidants in blueberries are what protected them against oxidative stress in their brains.
The next phase of the research is to see if the effects are long lasting.