There is currently an ongoing debate as to whether these calcium channel blockers increase the risk of heart attacks. It is also involved in the control of blood cholesterol levels. Increased calcium may lower blood cholesterol levels and reduce the risk of developing premature heart disease. Diabetics often have increased levels of calcium in their cells and the resulting disturbance in metabolism may play a role in some of the complications of diabetes such as heart disease and cataracts . Calcium from milk and milk products is absorbed more easily than that from vegetables.
Absorption is enhanced by vitamin D, proteins, lactose, phosphorus, stomach acid and magnesium.
Lactation increases the ability of women to absorb calcium after weaning or the resumption of menstrual periods. Deficiency and moderate exercise also increase absorption and the efficiency of absorption decreases as intake increases. Calcium competes with zinc, manganese, magnesium, copper and iron for absorption in the intestine and a high intake of one can reduce absorption of the others. Adults excrete 400-600mg of calcium daily. Signs of severe calcium deficiency include abnormal heartbeat, muscle pains and cramps, numbness, stiffness and tingling of the hands and feet and dementia.