Calcium, vitamin D will not protect bones, study says
If taking more vitamin and mineral supplements is part of your plan for a healthier new year, a new study might prompt you to reconsider.
Researchers who scoured medical literature for evidence that calcium and vitamin D pills could help prevent bone fractures came up empty. Their analysis focused on adults older than 50 who lived on their own (not in a nursing home or other type of residential care facility).
The researchers, led by Dr. Jia-Guo Zhao of Tianjin Hospital in northeastern China, combed through clinical trials, systematic reviews and other reports published since late 2006. They identified 51,145 people included in studies assessing the role of calcium and/or vitamin D in preventing bone fractures. Their findings appeared in Tuesday’s edition of the Journal of the American Medical Association.
Among the 14 trials that pitted calcium supplements against either a placebo or no treatment, there was no statistically significant relationship between use of the mineral (in pill form) and the risk of suffering a hip fracture. Nor was there any clear link between calcium supplements and fractures involving the spine or other bones.
Even when the researchers accounted for each study participant’s gender, history of bone fractures, the amount of calcium they consumed in their diets and the dose of the calcium pills they took (if they did), there was no sign that supplements were helpful.
An additional 17 trials examined the role of vitamin D, which helps the body absorb calcium. Again, they found no statistically significant link between supplement use and hip-fracture risk. Ditto for fractures in the spine and elsewhere. Among certain subgroups, they found that for people who started out with at least 20 nanograms of vitamin D per millilitre of blood, adding more vitamin D through supplements was associated with a greater risk of hip fractures. The same was true for people who took high doses of vitamin D supplements just once a year.
Finally, there were 13 trials involving people who took a combined calcium-vitamin D supplement. As before, there was no statistically significant link between supplement use and the risk for any kind of fracture or combination of fractures.
It’s still possible that calcium and vitamin D supplements are useful for people who live in nursing homes or other residential facilities, the study authors wrote. Such people are more likely to have osteoporosis, due to a combination of poor diet, less sun exposure and other factors.
But for older adults who live on their own, they wrote: “These findings do not support the routine use of these supplements.”