Extra Calcium May Harden a Man’s Heart

Cardiovascular disease death risk increases among men taking high doses of calcium supplements

(RxWiki News) Older people may take calcium supplements to improve bone health. For men, however, downing large doses of this nutrient may increase the chances of getting heart disease.

A previous study reported that 50 percent of older men and 70 percent of older women in the United States use calcium supplements. Recently, researchers discovered that men who consumed high amounts of extra calcium were more likely to get cardiovascular disease, although this risk did not apply to eating calcium-rich food.

"Too much of a dietary supplement may be unhealthy."

Qian Xiao, PhD, a researcher with the National Cancer Institute in Bethesda, Maryland, and her fellow scientists analyzed details on 388,229 men and women ages 50 to 71 years. Participants were from the National Institutes of Health-AARP Diet and Health Study.

During an average 12 years of follow-up, investigators identified 7,904 deaths from cardiovascular disease in men and 3,874 deaths from cardiovascular disease in women. Supplements containing calcium were used by 51 percent of men and 70 percent of women.

Compared with non-supplement users, men with an intake of supplemental calcium of more than 1,000 mg/day had a 20 percent greater risk of death from cardiovascular disease. In women, taking supplemental calcium was not associated with cardiovascular disease death

Calcium is one of the most important minerals for the human body, according to Medline Plus, a service of the US National Library of Medicine and the National Institutes of Health. Older women and men may need extra calcium to prevent their bones from becoming thin, a condition called osteoporosis.

The Institute of Medicine of the National Academies says that the estimated average requirement of calcium is 800 mg per day for males aged 51 to 70 years old and 1,000 mg for women in that age range.

Calcium supplements come in two primary forms: calcium carbonate and calcium citrate. Calcium carbonate is in common over-the-counter antacid products such as Tums and Rolaids. Each tablet provides 200 to 400 mg of calcium. Calcium citrate is a calcium salt, which is more easy to absorb but a more expensive supplement.

Research from Creighton University stated, “The retail cost per 1,000 mg of ingested calcium was between $0.16 and $0.20 for the marketed calcium carbonate product and between $0.24 and $0.38 for the marketed calcium citrate product.”

The authors of this study wrote that the health effect of calcium supplements on “nonskeletal outcomes” has become “increasingly contentious.”

Dr. Xiao told dailyRx News, “Some previous studies raised concerns about the potential adverse effect of calcium intake on cardiovascular health. We observed an increased risk of death from heart disease in men who reported taking supplements containing calcium, compared to men who did not report taking supplements containing calcium. Calcium from dietary sources was not related to risk of death from cardiovascular disease in men or women. Our study adds to the broader evidence base on this topic; however, we need more studies to clarify this possible relationship and the underlying mechanism.”

In a related commentary, Susanna C. Larsson, PhD, of the Karolinska Institutet, Stockholm, Sweden, wrote: "More large studies are needed to further assess the potential health risks or benefits of calcium supplement use on cardiovascular disease morbidity and mortality. Meanwhile, a safe alternative to calcium supplements is to consume calcium-rich foods, such as low-fat dairy foods, beans and green leafy vegetables, which contain not only calcium but also a cocktail of essential minerals and vitamins."

This study was first published February 4 in JAMA Internal Medicine. The research was supported by the Intramural Research Program of the National Institutes of Health, National Cancer Institute and National Institute of Aging, National Institutes of Health and the US Department of Health and Human Services.

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Review Date: 
February 7, 2013