Under normal conditions, the level of calcium in the blood is carefully controlled. When blood calcium levels fall.calcium is released from bones to restore proper blood levels. When blood calcium levels rise.the excess calcium may be stored in bone or passed out of the body in urine and stool.
This control depends upon:
The amount of calcium in the diet.
The amount of calcium and vitamin D absorbed by the intestines.
The amount of phosphate in the body. (For more information.see the medical test Phosphate in Blood.)
The production of certain hormones, including parathyroid hormone, calcitonin.