Here are a few notes about the biological role of sodium.
Sodium is a vital element. The human diet must contain a sensible amount of sodium. The sodium cation is the main extracellular (outside cells) cation in animals and is important for nerve function in animals. The importance of sodium as salt in the diet was recognized well before sodium itself was understood to be an element. This recognition formed the basis of trading of salt deposits lining the Dead Sea in biblical times by the Romans. Prolonged sweating results in sodium ion loss in sweat and it is most important that the sodium ion is replaced through proper diet. Hazards and Risks
Here are a few notes about the hazards and risks associated with sodium.
Sodium metal is a major fire risk. Sodium compounds are relatively harmless as long they are as not ingested in excess. This includes common salt, NaCl. People with heart diseases may need to ensure their diet does not contain too much sodium.