What’s the Best Supplement for Your Bones?

For years women (and more recently, men) have been told to take calcium supplements to help avoid osteoporosis later in life. Or rather, they should take calcium in combination with vitamin D. Some recent studies have suggested that vitamin D is even more important than calcium in preventing bone less, while others have led to the opposite conclusion.

In a review of 12 studies, researchers compared the effects of taking vitamin D supplements with the effects of taking calcium alone or calcium and vitamin D together or a placebo (Arch Intern Med 2009;169(6):551:561). They chose to focus on people who were 65 years of age or older, likely because the elderly are more at risk of long-term consequences when they break bones.

The researchers pooled the results of 12 well-designed studies of calcium and vitamin D supplementation. These studies included over 42,000 men and women and each study lasted between 1 and 7 years. First they looked at all of the test subjects who had received some kind of vitamin D supplement and compared them with those people who had received no vitamin D at all. Those who received vitamin D were about 14% less likely to break a bone, other than the spine. (Results were separated by vertebral fracture [breakage of the spinal bones] and non-vertebral fracture [bones other than in the spine]).

Then the scientists compared those test subjects who received vitamin D with those who did not, and broke down the results by how much vitamin D a subject received. Those who received a low dose of vitamin D (under 400 IU per day), their risk of bone fractures actually did not change at all as compared to those who did not take vitamin D.

On the other hand, those men and women who received higher doses of vitamin D (over 400 IU per day) had a nearly 20% lower risk of bone breaks than those who did not take vitamin D.

What's really amazing is that taking vitamin D with calcium - as opposed to taking vitamin D alone - did not seem to make any difference.

What this means for you

This is by no means a license to drop your calcium supplements in the trash or to stop taking your prescription calcium medication. This does not say that calcium makes no difference at all to your risk of bone breaks. It does say that if you are over 65 and are not taking vitamin D supplements, and your doctor thinks it's a good idea, you might consider taking at least 400 IU of vitamin D every day.

First posted: April 29, 2009