Although no single food is best for overall health, eating well-balanced meals can sharpen brain function and help the organ to grow. “With so much focus on brain science and mental health, it is essential we consider the powerful brain intervention at the end of our forks,” says Drew Ramsey, MD, an assistant clinical professor of psychiatry at Columbia University College of Physicians and Surgeons.

According to Ramsey, five categories of super affordable foods are key for optimal brain function: seafood, greens, nuts, beans and a little dark chocolate.

Buy fish, such as wild salmon; fruits, such as blueberries; veggies, such as kale and other leafy greens (frozen is fine); and canned beans and other legumes, such as lentils.

In addition, foods such as nuts, whole grains, chocolate and select meats can be purchased in bulk. And eat foods in season, Ramsey suggests, since that’s when they’re most flavorful and nutritious.