Calcium along with Magnesium and phosphorus contribute to the mineralisation of bone by entering bone fluid from the blood and subsequently attaching to bone proteins. Peak bone mass occurs in early adulthood with bone mass often beginning to decline in the fifth decade of life.

Non-bone calcium in the blood is also vital in muscle contraction, blood clotting, nerve conduction, enzyme regulation and membrane permeability.

Calcium serves to mediate the action of many hormones and neurotransmitters within the cell. Calcium can act as a messenger to trigger immune cell activation.
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3). Most limestone is composed of skeletal fragments of marine organisms such as coral, forams and molluscs.


Prolonged use of Lithium – for Bipolar disorder – in some genetically susceptible individuals – can lead to problems with the parathyroid gland. If levels of parathyroid hormone get to high then calcium concentrations in the blood also start elevating. Hormone levels that are out of range are not good and leads to serious, life-threatening symptoms. The parathyroid glands (there are 4) may enter into a state of uncontrolled growth. Get tested regularly.