Calcium is present in your blood, teeth and bones. It aids in biological functions such as nerve conductivity, maintaining heart rhythm and hormone secretion. It also plays a vital role in several aspects of cardiovascular function, and increased calcium intake is associated with lower blood pressure, according to the Office of Dietary Supplements.
Calcium in Your Body
Though a certain quantity of calcium steadily circulates through your bloodstream, the vast majority of this mineral occurs in your bones and teeth, where it provides strength and structure. The calcium in your bones is constantly being reabsorbed into your blood and redeposited into your bones. As your body is young and growing, the deposit of calcium exceeds the reabsorption, allowing bones to lengthen and thicken. In your adult years, the rate of calcium reabsorption balances the rate of deposit, to maintain your skeletal structure. As you get older, your body tends to reabsorb more calcium than it deposits. This deficient calcium deposit leads to bone loss and osteoporosis. When you don't obtain enough calcium in your diet, your body may absorb more of it from your bones, increasing your chances of bone thinning.
Calcium and the Cardiovascular System
Your cardiovascular system relies on calcium to mediate the constriction and dilation of blood vessels. The effect of calcium supplementation on heart attack risk is a topic of debate among physicians. According to Dr. Martha Grogan of Mayo Clinic, some believe that calcium could gather in the arteries, increasing the risk of atherosclerosis and heart disease. The Office of Dietary Supplements states that calcium is thought by some to reduce your risk of heart disease by decreasing the absorption and increasing the excretion of fats, but the majority of evidence does not suggest a link between calcium and heart disease. This lack of conclusive evidence on the effects of calcium on heart disease also extends to its relationship to blood pressure.
Calcium and Hypertension
Hypertension, or high blood pressure, can occur when your blood vessels narrow, causing increased pressure on the volume of blood that flows through your veins and arteries. According to the Office of Dietary Supplements, the relationship between calcium and blood pressure remains unclear and may vary among populations. Those with high blood pressure may experience a lowering of systolic blood pressure by 2 to 4 mmHg, but if your blood pressure is already within healthy range, calcium may have no effect on it at all.
Sources
Calcium is best obtained in its natural form -- through dietary sources such as low-fat milk, tofu and kale. If you are considering taking calcium supplements, educate yourself regarding the various forms available on the market. According to HelpGuide.org, the daily recommended dosage of calcium is 1,000 mg for most adults, but you should only take 500 mg at a time because that is all your body can absorb at once.
