A 4-ounce serving of salmon has approximately 2,000 milligrams of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), omega-3 fatty acids that serve as oil for the brain’s hardware by helping nerve cells communicate with one another. Thirty-five percent of your brain consists of fatty acids like these, but they can decline as the years stack up. A 2008 University of Cincinnati study, for instance, found that the brain tissue of 65- to 80-year-olds contained 22 percent less DHA than the brain tissue of 29- to 35-year- olds. “If you want to keep your wits about you as you age, start consuming omega-3s now,” says William Harris, Ph.D., a nutrition researcher at the University of South Dakota. Why is wild so important? Because farmed fish, which are fattened with soy, can be as high in inflammatory omega-6 fats as a cheeseburger. If in doubt, opt for sockeye salmon, which can’t be farmed and is always wild. Aim for at least two servings a week, says dietitian Joan Salge Blake, author of Nutrition and You.