Essential to life, but in minute quantities, mankind has been consuming salt since Neolithic times. It is used both as a preservative and a condiment. Until the 19th century, salt was a rare resource, as it was geographically poorly distributed. In the 20th century, it became an inexpensive industrial product, added to most foodstuffs in the food industry. Nowadays, it is consumed in excess and widely criticised because of health risks.