Sodium allows for the transmission of nerve impulses and is therefore essential for human life. It is a metal that is soluble in water and it easily combines with other elements. When it combines with chloride, it creates common table salt. In ancient times, humans figured out that salt acts as a preservative. This discovery made it possible to preserve food, such as meat, over the winter so that it could be consumed in the winter or spring. Salt became extremely important as an economic product, and humans began consuming more salt in the foods they ate.