AlexRathsGetty Images When it comes to keeping your brain healthy as you age, your diet plays a big role. Eating a variety of foods is critical to getting the vitamins and nutrients your brain needs to keep performing at its best. “A large body of literature has found that certain nutrients, flavonoids, unsaturated fats, and omega-3 fatty acids are associated with slower cognitive decline and reduced risk of dementia,” says Puja Agarwal, Ph.D., a nutritional epidemiologist and assistant professor in the Department of Internal Medicine at Rush Medical College in Chicago. Eating whole foods is the best way to get those nutrients. That’s because supplements don’t work as well in a vacuum. When you eat a balanced diet, though, the combination of vitamins, minerals, healthy fats (and more) helps the body better absorb the nutrients it needs.