Salt puts up our blood pressure. Raised blood pressure (hypertension) is the major factor which causes strokes, heart failure and heart attacks, the leading causes of death and disability in the UK. There is also increasing evidence of a link between high salt intake and stomach cancer, osteoporosis, obesity, kidney stones, kidney disease and vascular dementia and water retention 
Salt is something Humans need in small amounts but most of us eat too much of it. We should take care how much salt we put into our food. Another problem is prepackaged food and Fast food where frequently there is more salt than we realize.