Calcium Doesn’t Boost Bone Health

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A new study finds extra calcium in a diet probably won't make a difference when it comes to bone health. REUTERS/John Gress

As a people age, they are at higher risk for fractures, which is why physicians have long recommended adding more calcium to one’s diet—through either eating foods rich in the mineral or taking supplements. But a new study published Tuesday in BMJ suggests grabbing that extra yogurt probably won’t prevent thinning of bones.

Researchers in New Zealand conducted a systematic review of two randomized, controlled trials and more than 40 observational studies on calcium intake to prevent bone fractures.

The researchers found the connection between calcium supplements and increased mineral bone density was not statistically significant: only 1 to 2 percent. Eating more foods with calcium appeared to impact bone density by even less.

“Calcium supplements have small inconsistent benefits on fracture reduction but probably have an unfavourable risk: benefit profile,” the researchers wrote in the conclusion of their study. “Collectively, these results suggest that clinicians, advocacy organizations, and health policymakers should not recommend increasing calcium intake for fracture prevention, either with calcium supplements or through dietary sources.”

Currently, it’s recommended that older men and women get at least 1,000 to 1,200 milligrams of calcium a day to maintain bone density. A whopping 30 to 50 percent of women over age 50 currently take a calcium supplement of some kind. Many people also take vitamin D supplements, which helps with calcium absorption.

Because of recently reported safety issues, health experts now recommend people choose the right foods—such as dairy, leafy greens and seafood—rather than head to the supplement aisle.

An accompanying editorial explains the individual studies done thus far on dietary calcium are too tenuous to make any definitive conclusions about the benefits of supplementing one’s intake either with over-the-counter supplements or through diet.

“Overemphasis on high intakes of calcium without firm scientific evidence has probably hindered development in this research area,” wrote Karl Michaëlsson, a professor at the department of surgical sciences at Uppsala University in Sweden. “The evidence currently available, however, gives us a strong signal that calcium supplements with or without vitamin D do not protect older people in general from fractures.”

The editorial also points out that this opinion is shared by the U.S. Preventive Services Task Force, a government-funded panel that makes recommendations for preventive care based on a comprehensive analysis of scientific research on the topic. Their analysis even determined that calcium supplementation alone might actually increase the risk for hip fracture, one of the known adverse side effects of getting too much of the nutrient.

Some research suggests that too much calcium may also increase one’s risk heart attack and stroke. Another study published several years ago in BMJ found that women who took calcium beyond the recommended dose had a 49 percent higher risk for death from cardiovascular disease and a 40 percent higher risk for overall mortality. Other adverse effects of calcium include kidney stones and acute gastrointestinal illness.