Blueberries have high levels of phenolic compounds and antioxidants, which can benefit cognition. In a trial with 38 older adults, scientists sought to determine if eating a reasonable number of the berries daily could elevate these levels enough to improve cognition. They found that after 90 days of eating 24 grams of dried or 1 cup of fresh fruit per day, the group demonstrated improved cognitive performance and the levels of spotlighted chemicals were increased in the blood.
Rutledge GA, et al. Blueberry phenolics are associated with cognitive enhancement in supplemented healthy older adults [published online ahead of print December 17, 2020]. Food Funct. 2020;10.1039/d0fo02125c. doi:10.1039/d0fo02125c.