Calcium is the most abundant mineral in the body. Ninety-eight percent is found in the bones, 1% in teeth, and 1% in other tissues. When the body is at rest, calcium is pulled out of the bones to be used elsewhere, establishing the importance of daily adequate intake of the mineral and of exercise. Calcium helps regulate nerve transmissions and  along with magnesium, is important for cardiovascular health. If muscles do not have enough calcium, they cannot  contract or if contracted, do not relax, which results in cramps.
The mineral is good for relaxation and improves the quality of sleep. During the hormonal shifts of menopause, the dominance of the parathyroid hormone causes calcium to be removed from bone resulting in osteoporosis.
Requirements for calcium may vary depending on how much each individual absorbs and retains. Pregnant women need to ingest at least 1200 mg a day, especially in the last two months because over half of the calcium in an infants body is deposited at that time. Moderate amounts of protein, lactose, and butterfat enhance absorption of calcium, therefore, low-fat rather than nonfat milk products should be part of the diet, especially for children.
Excess protein in the diet causes a urinary loss of calcium. High intakes of calcium interfere with the absorption of  other minerals including iron, zinc, and manganese, disrupt the functioning of the nervous and muscular systems, and may prevent blood coagulation.