Sodium

sodium a chemical element essential to life. Communications between nerve cells depend on letting sodium ions (electrically charged atoms) in through the cell membrane, and cells contain a mechanism called the ‘sodium pump’ which constantly removes the excess. Up to a third of the energy used by the cell goes to keeping this ‘pump’ running.

Sodium in its pure state is an inflammable metal and it is always found in compounds or, in cells, as ions (charged atoms). The most abundant sodium compound, and the form in which most sodium is consumed, is common salt, sodium chloride. Other compounds used in foods include bicarbonate of soda (sodium hydrogen carbonate) and Chile saltpetre (sodium nitrate). Caustic soda (sodium carbonate), the most powerful of all alkalis, is used to clean and disinfect kitchen surfaces.