Sodium is a chemical element that is a soft, silvery-white highly reactive metal. It is too reactive to occur in pure elemental form in nature, but is found as part of many minerals.
Sodium is the sixth-most abundant element on earth, comprising around 2.6 percent of the Earth's crust. Its reactivity is due to a single electron in its outer electron shell which it readily donates. This leaves a sodium ion which has chemical properties different from elemental sodium.
For example, sodium can react with the gaseous element chlorine to produce sodium chloride or common table salt. When table salt is dissolved in water it ionizes to produce a positively charged sodium ion and a negatively charged chloride ion.
The human body can't live without a certain amount of sodium in the diet. However, a normal diet provides ample to excessive amounts. Sodium is an important component of the more than 8 quarts of secretions produced by the body every day. These secretions include saliva, gastric and intestinal secretions, bile, and pancreatic fluid.
The sodium ion is also needed to transmit nerve impulses, contract and relax muscle fibers — including those in the heart and blood vessels — and to maintain a proper body fluid balance. However, excess amounts of sodium in the body can increase blood pressure because it holds excess fluid in the body. This puts a burden on the heart that can increase the risk of stroke, heart failure, as well as other serious health issues.
Table salt is typically mined from underground salt deposits, while sea salt is produced through evaporation of ocean water or water from saltwater lakes. They both have about the same basic nutritional value and roughly the same proportion of sodium.
Sea salt is often promoted as being healthier, but their main difference is in their taste, texture, and processing. Sea salt has a coarse, crunchy texture and stronger flavor. Whichever type of salt you enjoy and use, do so in moderation for good health.
Larrie Stone is a retired Dana College science professor.