By Jaimie Dalessio
You may want to pause before you take your next calcium tablet. In a large, long-term study of Swedish women, researchers found that calcium intake greater than 1,400 mg per day was associated with higher death rates. The increase in death risk was more pronounced in those who consumed high amounts of calcium in their diets and used calcium tablets, as much as doubling their death risk, compared to those who ate foods with a lot of calcium but did not take supplements.
Higher death rates were also observed among women who consumed fewer than 600 mg of calcium per day. Death rates did not increase in those whose total daily calcium intake fell between 600 and 1,400 mg per day.
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"We know calcium is important for your bone health," says Joan Salge Blake, MS, RD, a clinical associate professor of nutrition at Boston University who did not work on the study. "After age 30, it's not so much adding to bone mass but making sure you don't withdraw from bone prematurely. Americans are living longer, so we have to make sure they are living better and have adequate bone mass later on in life so they can enjoy their later years with strong bones."
But many Americans don't meet their calcium needs with diet, so they turn to supplements. These findings highlight the idea that, with calcium and especially calcium supplements, "some is good, and more may not be better," Blake says.
The recommended amount of calcium intake for a woman between 51 and 70 years of age is 1,200 mg per day, according to the Food and Nutrition Board at the Institute of Medicine. But women are falling short of that guideline -- getting only an average of 895 mg of calcium per day, says Blake. That number comes from the latest "What We Eat in America" survey. Blake adds that Americans on average eat one and a half servings of dairy a day instead of the recommended three.
Calcium supplement use is common, especially for people who don't get enough nutrients -- or think they don't -- from diet. More than 60 percent of women middle-aged and older in the United States regularly take calcium supplements, the study authors write in their report.
Different Studies, Different Findings on Calcium
For this study, researchers at Uppsala University in Sweden pulled data from the Swedish Cause of Death Registry and the Swedish Mammography Cohort (established from 1987-1990), which followed women born between 1914 and 1948. The researchers obtained dietary questionnaires from the mammography cohort -- completed by 61,433 women at baseline and 38,984 women in 1997.
They measured reported calcium intake and death from all causes, in addition to death from cardiovascular disease, coronary artery disease (involving reduced blood supply to the heart due to narrowing of the arteries), and stroke. While the findings, published today in the British Medical Journal, show an association between high calcium intake in women and higher death rates from all causes and cardiovascular disease, they did not show such an association with stroke death rates.
Past observational studies have linked calcium supplement use to lower overall and cardiovascular death, but they have also linked the supplements to higher incidence of heart disease. Additionally, meta-analyses of studies have found an association between the use of calcium supplements and ischemic heart disease and stroke. Just last week, a study published in JAMA Internal Medicine found that men taking calcium supplements may be nearly 20 percent more likely to die from cardiovascular disease than those who do not take supplements. Interestingly, the researchers on that study did not find the same risk in women.
How Much Calcium Do You Really Need?
The upper intake level for calcium, a number which national guidelines recommend people stay under, is 2,000 for men and women 51 and older, according to the Institute of Medicine.
But it's difficult to go above that cap from diet alone, says Blake. When you already get enough calcium from food, calcium in excess often comes from supplements or from fortified foods. "Getting too much of something from supplements or overly fortified foods could be problematic, but getting too much from Mother Nature is not as risky, especially considering Americans aren't meeting recommended dairy servings."
The take-home message of this new study, for Blake, is that people wondering about calcium supplements should look at their own individual diets. If you're getting the right amount of dairy and eating well-balanced meals, "You can probably get this [a recommended, healthy amount of calcium] from your diet," she says.
"Too Much Calcium May Double Death Risk In Women" originally appeared on Everyday Health.