The importance of sodium

SODIUM compounds were known and used extensively during ancient times, but the element was not isolated until 1807 when an English chemist used a process called electrolysis to extract pure metal from sodium hydroxide. Although sodium was long believed to be a dietary essential, final proof was not obtained until 1918 when Osborne and Mendel conducted experiments on lab animals.

Although we hear much today about the adversities of salt, the body does require small amounts. Sodium is the chief cation (positively charged ion) in extracellular fluid and, acting with potassium, maintains proper body fluid balance. 

Sodium and potassium also work together to regulate muscle contractions and nerve stimulation. Sodium helps keep calcium and other minerals soluble in the blood and is necessary for the production of hydrochloric acid in the stomach. Acting with chlorine, sodium assists in keeping blood lymph healthy. It also purges carbon dioxide from the body.

Those on salt-restricted diets are advised to avoid all products containing salt. Studies are now indicating that if an adequate intake of water each day (8-10 glasses minimum) is maintained and caffeine drinks are eliminated, some dietary sodium becomes a benefit rather than a health risk. 

A chloride deficiency can occur when there is a loss of sodium caused by excessive sweating, chronic diarrhea, vomiting, and with some kidney disorders. These losses may result in metabolic alkalosis and disorders of the body's pH which can lead to coma and death. Therefore, maintaining an adequate sodium level is vital. 

However, it is estimated that the average consumption of sodium is more than twenty times the amount needed by the metabolism. Most fast foods and processed foods are oversalted. This interferes with the utilization of nutrients. The oversalting is done supposedly to improve flavor, but also to cause the kind of thirst that is a boon to the soft drink industry.

There is no official RDA, but the National Academy of Sciences estimates that a safe daily intake would be 500 mg. for most adults, but slightly higher amounts for pregnant or lactating women. 

Some other sources have suggested the RDA should be 2000-3500 mg. per day, but this seems excessive for the average need unless there is profuse sweating during prolonged exercise. It is also suggested that a single gram of sodium chloride for each kg. of water drunk is sufficient. More than 13 grams of sodium chloride daily can produce toxic effects.
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