Minerals such as potassium (K⁺) and calcium (Ca²⁺) are essential in the body. One main purpose of mineral ions such as these is to control water balance in the body, the way this is achieved is through the natural process of osmosis.
Osmosis is slightly different to diffusion in that it is the movement of water, as opposed to other substances. When there is more solutes on one side of the membrane, water will move to that side. Hence if there are too many minerals outside the cell, then the water in the cell will move into the surroundings, which causes the cell to dehydrate and can lead to cell death.
