Chrisandra Shufelt, MD, of the Barbra Streisand Women's Heart Center, led this review on calcium supplements and heart disease.
Getting enough calcium is important for preventing osteoporosis, a disease in which bones become fragile and easy to break. Women who are 50 years old or older are particularly susceptible to osteoporosis.
Many doctors recommend that women take 1,000 or 1,200 mg calcium supplements to protect against osteoporosis.
However, the role of calcium supplementation in developing heart disease has not been thoroughly investigated.
This review looked at previous trials that evaluated calcium intake and heart disease risks, including high blood pressure, cholesterol and inflammation.
The researchers found that most studies, including the National Health and Nutrition Examination Survey, pointed to small reductions in blood pressure with increased dietary and supplementary calcium.
The Women's Health Initiative study on calcium and vitamin D, which included 36,282 patients, found that calcium supplements did not increase or decrease blood pressure.
A one-year study including 223 postmenopausal women found that calcium supplements resulted in healthier levels of cholesterol. In another smaller study, cholesterol levels decreased 1.3 percent more in patients taking calcium supplements.
Much smaller trials have found that calcium results in a neutral or somewhat harmful effect on cholesterol levels.
Studies also have pointed to an inverse relationship between calcium levels and type 2 diabetes risk. The Women's Health Study, which included 10,066 women 45 years old or older, found that calcium intake was linked to lower rates of metabolic syndrome, a condition typically associated with obesity.
The Nurses' Health Study, which included 83,779 patients, found that patients taking 1,200 mg of calcium reduced their risk of type 2 diabetes by 33 percent compared with patients taking 800 mg.
Only a few observational studies have looked at calcium intake and heart problems. The Iowa Women's Health Study found that women who consumed the most calcium had a lower risk of dying from heart disease than women who consumed the least calcium.
Because some recent studies have shown a link between calcium and heart disease risk, the authors of this review called for additional research to be done on calcium supplements and heart health.
These researchers concluded that dietary calcium did not seem to increase the risk of heart disease, but the results of supplemental calcium studies were mixed.
They suggested that it is reasonable to encourage postmenopausal women to take calcium supplements because these women are at the greatest risk of osteoporosis.
This review was published in the American Journal of Lifestyle Medicine on December 5.
The research was supported by contracts from the National Heart, Lung and Blood Institutes and from the National Institute on Aging, as well as other grants. The authors did not disclose any conflicts of interest.