Potassium is a necessary mineral in daily nutrition; it assists in muscle contraction and in maintaining fluid and electrolyte balance in body cells. Potassium is also important in sending nerve impulses as well as releasing energy from protein, fat, and carbohydrates during metabolism. A shortage of potassium can cause a potentially fatal condition known as hypokalemia. Eating a variety of foods that contain potassium is the best way to get an adequate amount. Healthy individuals who eat a balanced diet rarely need supplements. Foods with high sources of potassium include bananas, avocados, celery and turnips, although many other fruits, vegetables, and meats contain potassium. is a chemical element in the periodic table. It has the symbol K (L. kalium) and atomic number 19. The name "potassium" comes from the word "potash", as potassium was first isolated from potash. Potassium is a soft silvery-white metallic alkali metal that occurs naturally bound to other elements in seawater and many minerals. It oxidizes rapidly in air, is very reactive, especially in water, and resembles sodium chemically.