Salt is one of those dangerously tasty substances. We add the magical crystals of sodium chloride to almost everything that we cook or bake, and according to many public health experts, we add too much.
They want us to cut back, to lower our risk of heart attacks or strokes.
Yet when you really start looking for ways to do this, you run into a paradox and a scientific puzzle.
First, the paradox. Too much salt may kill us, but our bodies need some of it to survive.