Potassium works with sodium to regulate the water and acid-alkaline balance in the body. It works with calcium to help stimulate nerve impulses and muscle contractions. Potassium is an important mineral in kidney function and helps supply the brain with oxygen. As an electrolyte, potassium transmits electrochemical impulses to regulate the heartbeat.
A balanced diet that includes plenty of fruit and veg, usually supplies you with the potassium your body needs. However, certain illnesses (e.g. prolonged vomiting and diarrhea) and diuretics remove potassium from the body. People who need to replenish their electrolytes to treat or avoid dehydration often take potassium supplements.