Calcium Supplements And Heart Disease

Heart disease is the leading cause of death in the United States. Recently, a few studies reported that taking calcium supplements modestly increases the risk of heart disease; however, the data is inconsistent with other studies, especially when vitamin D supplements are taken concurrently. More research is required to better define the risk of heart disease associated with calcium supplements.

Possible Mechanism

The progression of cardiovascular disease could be augmented by excessive serum calcium levels. Excess calcium may deposit in blood vessels of the heart and other places, increasing plaque formation. A review study in the July 2010 issue of the "British Medical Journal" notes that a buildup of calcium in arteries of the heart is a risk factor for heart disease.

Calcium Supplements

The study in the "British Medical Journal" reported that calcium supplements at doses greater than 500 mg per day increase the risk of having a heart attack. However, another review of several clinical trials in the March 2010 issue of the "Annals of Internal Medicine" found that calcium supplementation produces a minimal risk of cardiovascular complications. More studies are required to determine the cardiovascular risk associated with taking calcium supplements, which are used by many people, especially postmenopausal women, to maintain bone health.

Vitamin D

Vitamin D is commonly taken with calcium supplements because it increases calcium absorption by the intestines. It additionally prevents a buildup of calcium in the arteries. A study in the January 2010 issue of "Annals of Family Medicine" reports that low levels of vitamin D are linked to a decrease in mortality from cardiovascular diseases. However, in the 2007 issue of "Circulation," a study of more than 36,000 female participants found that 200 IU of vitamin D administered along with 500 mg of calcium carbonate twice daily did not have any affects on coronary or stroke outcomes. This is possibly because the dose of vitamin D administered in this study is too low -- in fact, three times lower than the recommended dietary allowance of 600 IU per day. More research is needed to determine if vitamin D supplements are cardioprotective and negate the possible risk from excess calcium supplementation.

Dietary Calcium

A review of the literature in the "British Medical Journal" noted that, in two studies, women with high intakes of dietary calcium had between a 30 and 40 percent reduced risk of cardiovascular death, although this effect was not observed in men. This review also noted that increases in serum calcium levels are higher after supplement intake than with equivalent doses from dietary sources of calcium. This may account for the differences in the effects of calcium supplements and increased dietary intake of calcium on the cardiovascular system. High blood pressure is a primary risk factor for heart disease. According to the American Heart Association, results from a clinical trial with more than 28,000 female participants suggested that an increased dietary intake of low-fat sources of calcium and vitamin D decreases the risk of developing hypertension. In contrast, calcium and vitamin D supplements did not have any affects on blood pressure.