Sodium
Sodium plays an essential role in the body. It is responsible for regulating body water content as well as electrolyte balance. It is crucial to understand that the control of blood sodium levels directly depends on a balance between sodium excretion and absorption at the kidneys regulated by nerves and hormones.
Furthermore, sodium is also needed for the absorption of certain nutrients and water from the gut, and it is a component of common salt, called sodium chloride (NaCl).