Why is it not advisable for humans to drink distilled water?
As you said, distilled water is completly out of minerals/ions. The principle of diffusion is that reagents diffuse from high-concentrated to low concentrated places to reach an equilibrium. So normally, ions from the erythrocytes would diffuse into the plasma to reach that equilibrium. However, it is quite difficult for ions to pass the cell membrane which is not the case for water. So what finally happens is that the distilled water wants to dilute the ions in your erythrocytes, passes the cell membrane and the cells explode because they are too full. As consequence, you die because there is no oxygen transport anymore.