About 70 percent of older women and more than 50 percent of older men take calcium pills, spending $1.2 billion on them in 2012, according to the Nutrition Business Journal. But recent evidence suggests that getting calcium from pills might not be as safe or effective for some people as getting it from food.
For example, some emerging research suggests that calcium supplements may boost a person’s risk of heart attack. And it’s no longer clear whether taking calcium plus Vitamin D decreases the risk of bone fractures, a benefit for which it has long been recommended. Consumer Reports reviewed the research to help answer the latest questions on calcium supplements.
It’s not yet clear. In a 12-year study of 388,229 men and women ages 50 to 71, researchers did find a 37 percent elevated risk of heart disease death among men — but not women — who took more than 1,000 milligrams of calcium a day in the form of individual supplements. The study was published online in February in JAMA Internal Medicine.
But investigators found no clear association between either dietary or supplemental calcium intake and cardiovascular death in an analysis of data from 20,000 participants in the ongoing National Health and Nutrition Examination Survey. The findings appeared in the April issue of PLOS One.
And an analysis of studies published in the journal Nutrition Reviews found that some showed a possible link between calcium supplements and cardiovascular risk but that most studies didn’t show a statistically significant effect, good or bad.
So far, “there’s no plausible mechanism that has been identified” to explain the purported adverse effects of calcium supplements, says Connie M. Weaver, head of the nutrition science department at Purdue University and co-author of the review. But the hypothesis is that taking calcium in pill form might cause a spike in blood calcium levels, which could encourage hardening of the arteries. When you ingest calcium from food, it’s absorbed in smaller increments over the course of the day. Weaver and her colleagues are testing the hypothesis in animal studies.
Probably not — or at least there’s not enough evidence one way or the other with regard to most healthy people, according to a February announcement by the U.S. Preventive Services Task Force, an independent group that makes evidence-based recommendations.
The task force concluded that, for post-menopausal women, daily supplementation with 1,000 milligrams of calcium and 400 international units of Vitamin D3 had no effect on the incidence of fractures and that the evidence was “insufficient to assess the balance of the benefits and harms” of higher doses. It also advised against taking daily supplements with lower amounts of calcium or Vitamin D3 because the benefit is even less clear.
Those recommendations don’t apply to people who already have a history of fractures, osteoporosis or Vitamin D deficiency, or who live in nursing homes or assisted-living facilities.
If you already take calcium or are considering it, talk with your doctor about whether you need supplements or can instead get adequate amounts from your diet. (Ask also about Vitamin D, since it has been found to help prevent falls — a main cause of fractures — in some older adults.)
Unless you’re advised otherwise, calculate your daily intake of calcium from all sources, including fortified food, and aim for more than the amount recommended by the Institute of Medicine.
In addition to dairy products, good sources of calcium include such leafy greens as kale and fortified foods such as cereal, orange juice, soy milk and tofu. Calcium from all of those sources is best absorbed if your intake is spread out during the day.
For further guidance, go to www.ConsumerReports.org/Health, where more detailed information, including CR’s ratings of prescription drugs, treatments, hospitals and healthy-living products, is available to subscribers.