I saw an article in WebMD – Study: Eating More Blueberries and Strawberries is Linked to Better Brain Function With Age.
The researchers followed up with 16,000 women for more than 20 years to track their berry consumption and brain function. They found that those who ate the most berries had a slower rate of developing memory problems.
They tracked blueberries and strawberries in this particular study though I think they would have found similar results with other berries rich in antioxidants and anthocyanins, like raspberries, blackberries, elderberries and any other berries that have bright red, blue, and purple colors. These berries are all readily available in the US.
The acai berry and maqui berry from Central and South America are very popular for their high antioxidant values but are harder to come by because those properties decay rapidly if not handled properly. They are also more expensive because they have to be imported.
There are many studies on the PubMed website showing the ability of berries rich in antioxidants and anthocyanins to protect brain cells.
I prefer to drink mine. Find out more about the concentrated berry juice that I drink.
Disclaimer: I am not a doctor. If you think you have a medical condition then please see a qualified health practitioner.