A mineral that serves as an electrolyte and is involved in the balance of fluid within the body. Our bodies contain more than twice as much potassium as sodium (typically 9oz versus 4oz). About 98% of total body potassium is inside our cells. Potassium is the principal cation (positive ion) of the fluid within cells and is important in controlling the activity of the heart, muscles, nervous system and just about every cell in the body. Potassium regulates the water balance and acid-base balance in the blood and tissues. Evidence is showing that potassium is also involved in bone calcification. Potassium is a cofactor in many reactions, especially those involving energy production and muscle building.