First, there is the very important mineral magnesium. We now know that it is a necessary part of many enzymes that are critical to those chemical steps mentioned above. Phosphorus also plays a smaller part as do other minerals. If any of the many nutrients are missing from this complicated chemical process, the calcium doesn't get into bone or fingernails or hair, but is wasted. Osteoporosis is rarely caused by lack of calcium, but it is caused by inability of calcium to be converted into bone .
Cells contain the potassium, and the blood and interstital fluids are high in sodium.
The lack of zinc has been linked to both prostate problems and impotency, not to mention acne. I haven't even mentioned the toxic minerals. A simple, non-invasive test is available that does that. It comes with a computerized readout of several pages detailing every toxic level, and it checks balance between various minerals by ratio. This report makes it easy for the layman to understand and gives recommendations for the steps to correct imbalances or to eliminate toxic minerals over time.