Whether we like to believe it or not, science tells us that after the age of 45, our cognitive abilities start to decline. The older we get, the more the brain regions responsible for memory, attention, and perception begin to shrink and no longer communicate with one another as efficiently as they once did. Fortunately, there are plenty of science-backed strategies for keeping your brain sharp for longer. From the right diet to your dental hygiene and social life, here are the best ways to keep your brain in shape.