People need salt because it helps to maintain water balance in the body. It also supports the transmission of nerve impulses and the proper functioning of the muscles. Normally, the kidneys regulate the balance of salt in the body by storing it when the levels are low and excreting it in the urine when the levels are too high.
The consumption of small amounts of salt is necessary for life. The U.S. Department of Health and Human Services recommends that people consume no more than 2,300 milligrams of salt a day. This is about a teaspoon.
Though sea salt is promoted as being healthier than table salt, the two have about the same amount of sodium. Their tastes and textures are different because of the way they're processed.
Salt has been used as a preservative for thousands of years. It also is used as a seasoning to make otherwise bland foods taste better. Taste buds on the tongue, throat and palate have evolved to perceive saltiness.
Salt also is used for deicing roadways. It's used to make paper, polyvinylchloride, soap, synthetic rubber and plastics. It's also used to dye fabrics, tan hides, glaze pottery and remove impurities from aluminum processing.