This leafy green is packed with nutrients that prevent dementia like folate, vitamin E, and vitamin K. Just one-half cup of cooked spinach packs a third of the folate and five times the amount of vitamin K you need in a day. Maybe that’s why a 2006 Neurology study reveals that eating three servings of leafy green, yellow and cruciferous vegetables a day can delay cognitive decline by 40%. Of these three, leafy greens were found to be the most protective. Try your spinach drizzled with a little olive oil. Its healthy fats boost absorption of fat-soluble vitamins E and K.