decalcification /dēkal′sifikā″shən/ [L, de + calyx, lime, facere, to make] , loss of calcium salts from the teeth and bones caused by malnutrition, malabsorption, or other dietary or physiological factors, such as immobility. It may result, particularly in older people, from a diet that lacks adequate calcium. Malabsorption may be caused by a lack of vitamin D necessary for the absorption of calcium from the intestine; an excess of dietary fats that can combine with calcium to form an indigestible soaplike compound; the presence of oxalic acid, which can combine with calcium to form a relatively insoluble calcium oxalate salt; hormonal changes of menopause; or a relative lack of acid in the digestive tract, which can decrease the solubility of calcium. Other factors include the parathyroid hormone control of the calcium level in the bloodstream, the ratio of calcium to phosphorus in the blood, and the relative activity of osteoblast cells that form calcium deposits in the bones and teeth and osteoclast cells that absorb calcium from bones and teeth. Bone tissue tends to be maintained in quantities no greater than needed to meet current physical stress. Therefore inactive and, particularly, bedridden people lose calcium from their bones; osteoclastic activity exceeds osteoblastic activity, and decalcification occurs. See also calcium, mineral.
