Walnuts (Juglans regia) are a tree nut belonging to the walnut family. They originated in the Mediterranean region and Central Asia and have been part of the human diet for thousands of years. These nuts are rich in omega-3 fats and contain higher amounts of antioxidants than most other foods. Eating walnuts may improve brain health and prevent heart disease. Walnuts are most often eaten on their own as a snack but can also be added to salads pastas breakfast cereals soups and baked goods. Theyre also used to make walnut oil an expensive culinary oil frequently used in salad dressings. There are a few edible walnut species. This article is about the common walnut sometimes referred to as the English or Persian walnut which is grown worldwide. Another related species of commercial interest is the eastern black walnut (Juglans nigra) which is native to North America.