Everybody knows about blueberries. Most people know them as a "superfood." "Super", in the sense that they are really good for your brain. I'm actually eating some right now as I write this. Actually, eating blueberries is something I do daily. It is part of my diet so my memory is always at its peak.
There has been a bunch of research done on blueberries, and it turns out that they have compounds in them that boost neuron signals, which in turn help with memory and cognition. Eating blueberries and maintaining a diet rich in fruits and veggies with deep pigments can keep your brain machinery sharp and boosts the potency of your neuron signals. The antioxidants in blueberries stimulate the flow of blood and oxygen to the brain, keeping your mind fresh.
Eating healthy is a very important aspect of maintaining brain health. So do it. Then go memorize a pack of cards :D