Potassium is the principal positively-charged ion inside body cells. It is vital for muscle contraction, nerve impulses, and function of heart and kidneys. It is necessary for regulation of the fluid-electrolyte balance within cells and in regulating blood pressure. There’s some evidence that diets high in potassium rich fruits and vegetables reduce the risk of hypertension and stroke.
Food Sources: Fresh foods of all kinds. fruits, vegetables, whole grains, legumes, etc.
Sodium is the chief ion used to maintain the volume of fluid outside the cells. Sodium attracts water. It is essential to muscle contraction and nerve transmission. The connection between sodium and high blood pressure in salt sensitive people is well known. This may not be due solely to an increased sodium intake. As you can see calcium and potassium may also factor into the blood pressure equation. Diets rarely lack enough sodium.
Food Sources: almost all processed food, salt, and soy sauce.