During the Mars-500 experiment they ran a low-salt-diet test.
They found that the body cycle for salt is more complicated that thought before and "It is not only worthwhile reducing the amount of salt added to food for those who are ill - even the blood pressure in healthy individuals such as the Mars500 test subjects was reduced." [1]
https://en.wikipedia.org/wiki/MARS-500
[1] http://www.astrobio.net/pressrelease/4329/lessons-from-mars-...