Table salt, or halite, is a chemical
compound known as Sodium chloride and is harvested by the
evaporation of seawater. It is commonly used as a flavor
enhancer and preservative for food.
Salt or Sodium chloride is important to life on earth. Most
tissues and body fluids contain a varying amount of NaCl. Humans
are unusual among primates in secreting large amounts of salt by
sweating.
There are 32 references to salt in the Bible, the most familiar
probably being the story of Lot's wife, who was turned into a
pillar of salt when she disobeyed the angels and looked back at
the wicked city of Sodom.
Salt's preservative ability was also a foundation of
civilization. It eliminated dependency on the seasonal
availability of food and allowed travel over long distances. By
the Middle Ages, caravans consisting of as many as 40,000 camels
traversed 400 miles of the Sahara bearing salt, sometimes
trading it for slaves.
Salt was once one of the most valuable commodities known to man.
In the Roman Empire, salt was sometimes even used as a currency.
Throughout much of history, it influenced the conduct of wars,
the fiscal policies of governments, and even the inception of
revolutions. Salt was taxed, from as far back as the 20th
century BC in China.
While most people are familiar with the many uses
of salt in cooking, they might be unaware that salt is used in a
plethora of applications, from manufacturing pulp and paper to setting
dyes in textiles and fabric, to producing soaps and detergents.
Salt is commonly used as a flavor enhancer for food and has been
identified as one of the basic tastes. Ironically, given its history,
this has resulted in large sections of the developed world ingesting
salt massively in excess of the required intake, particularly in colder
climates where the required intake is much lower. This causes elevated
levels of blood pressure in some, which in turn is associated with
increased risks of heart attack and stroke.
The salt we buy for consumption today are not purely sodium chloride as
most people assume. In 1911 Magnesium carbonate was first added to salt
to make it flow more freely. In 1924 trace amounts of iodine were first
added, creating iodized salt to reduce the incidence of simple goiter.