April 27, 2005 -- Two new studies question whether vitamin D and calcium supplements can protect mobile, high-risk, over-70 seniors against future bone fractures.
Earlier studies showed that vitamin D and calcium supplements reduced the risks of fractures in elderly women.
But two new studies fail to show a fracture prevention effect for the popular dietary supplements in the elderly.
Adrian Grant, MD, director of the Health Services Research Unit at the University of Aberdeen, Scotland, studied 5,292 elderly, mostly female patients who already had a fracture. During two to five years of follow-up, those taking vitamin D and calcium supplements had no fewer new fractures than those who didn't take supplements. The study appears in the April 28 online edition of The Lancet.
David Torgerson, PhD, director of the York Trials Unit at the University of York, England, headed the other study, which followed 3,314 women who were frail, in poor health, or who had previous fractures. Over two years, those taking the supplements had no fewer fractures than those who did not. The study appears in the April 30 issue of the British Medical Journal.
"If you are at risk of bone loss and fracture, you need something else other than calcium and vitamin D to reduce your risk," Torgerson tells WebMD. "If you are reasonably healthy and have reasonable diet, there is no reason to waste your money on calcium or vitamin D supplements."
"Although vitamin D and calcium won't do any serious harm, it does require taking something every day and it does have a cost," Grant tells WebMD. "We know there are other approaches that can prevent further fractures. So if people are at high risk, they may wish to seek a doctor's advice on bone-active treatments."
Americans up to age 50 are advised to take 200 IU (international units) of vitamin D daily. From ages 51 to 70, the advised dose is 400 IU. For people over age 70, it's 600 IU. Vitamin helps promote the absorption of calcium. The recommended intake for adults over the age of 50 is 1,200 milligrams of calcium per day.
Modest but Important Vitamin D, Calcium Effects Missed?
What should seniors make of these new findings? Not too much, argues Philip Sambrook of the Institute of Bone & Joint Research in Sydney, Australia, in a Lancet editorial accompanying the Grant study.
Sambrook notes that more than a third of the participants in the Grant study did not take their calcium/vitamin D supplements as they were supposed to.
"Overall, the data are still consistent with a therapeutic benefit of vitamin D on fractures in people deficient in vitamin D," Sambrook writes.
He also says since vitamin D levels were not assessed at the start of the study it is not clear what effects might be expected in vitamin D-replete people.
Supplements Have Their Place
Perhaps a more important criticism of the studies comes from John Hathcock, PhD. Hathcock is vice president for scientific and international affairs at the Council for Responsible Nutrition, a group that represents the supplement industry.
Hathcock says that vitamin D and calcium by themselves are not a total insurance policy against fractures in the elderly. Earlier studies, he points out, show the reduction in fractures to be in the 30% to 40% range. The Torgerson study did not have enough participants to detect a reduction in fractures of less than 30%. And Hathcock says the Grant study, too, could easily have missed such an effect.
"These studies do not exclude modest but important benefits for vitamin D and calcium supplements," Hathcock tells WebMD. "This should not suggest that anybody stop taking calcium and vitamin D supplements."
Grant says elderly people at risk of fracture should be taking medications that build new bone mass. Such patients, he says, also need supplements.
"People who are taking very bone-active drugs, like bisphosphonates, are encouraged to take vitamin D and calcium at the same time," he says. "Those who now are just taking vitamin D and calcium should consider -- with their doctors -- whether they would benefit from bone-active medications."