Sodium deficiency is rare in humans - the physiological need for salt has been calculated at around 1.3 grams per day for an adult - but, given the opportunity, most people consume far more than this. Leading to the idea that there must be an inbuilt preference to consume more salt than is actually required.
Bearing in mind that excess salt intake has been linked to a number of health hazards ( see: Salt and hypertensionplugin-autotooltip__plain plugin-autotooltip_bigSalt and hypertension
It's been known for several thousand years that an excess intake of common salt can have adverse effects on the cardiovascular system. (ref.)
Recent research has shown unequivocally that long-term high intakes of salt can cause a range of problems in otherwise healthy individuals. Dietary specialists worldwide have now come to an agreement that salt intake for adults should be no more than 5g. per day. ) , it's not clear how or why the desire for salt has evolved above the level for healthy living.
Throughout life, our love of salt peaks and dips. Salt flavours our food and promotes its consumption and thus possibly obesity; it sustains and protects us in physical exertion, may occasionally be remedial, contributes to our growth and ailments and generates controversy
Nonetheless, salt itself is inedible.
The attribution of this complexity to early dietary exposure and processed food is unsubstantiated, as well as inadequate.The fundamental question persists of why we love the taste of salt."
Source : British Journal of Nutrition Volume 123 Issue 11