What is K (potassium) important for?

Potassium plays a major role in blood pressure control as it lessens the effects of sodium by increasing sodium excretion. It affects the balance of fluids in the body. Other good sources of potassium can be found in bananas, white beans, avocado, spinach, milk, etc.  The recommended intake of K is 4700 mg per day. Other dietary factors that can affect blood pressure include the intake of salt, fiber, dietary fat/cholesterol, protein, and minerals (calcium/magnesium). Too much potassium can be harmful to elderly with kidney disease due to the kidneys not being able to efficiently remove potassium from the blood. http://www.heart.org/