I just read a book called "The Calcium lie", and in this book we hear that in the good old days before we got refrigerator we salted our food, and sea salt and rock salt contains all the minerals we need.
We learned that salt is dangerous, and avoided it.
During years we got to little minerals since we avoided the real salt, and the soil where we grow our food also has less minerals. Our body craves the important minerals, and thats why people eat McDonalds; we get fatty fries and burger and sweet coca cola, and we eat it because our body says we need it for our minerals.
Dont know if I agree with everything in the book but it left me thinking...