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|All Health and Nutrition Bites|
Should you take Vitamin D for your bones?
About a year ago a friend of mine started jogging. Like me, she was a bicyclist, but she was looking to change up her exercise routine. While bicycling gives you plenty of leg muscle, however, it doesn't get your shinbones used to the pounding that they take in running
Vitamin D in Foods
There is mounting evidence that many of us are increasingly deficient in Vitamin D. While there is some controversy about the health impact of this it seems that changes in our diet in the last few years towards fewer foods rich in Vitamin D has led to a much lower intake. Likewise, with the recommendations on avoiding the sun and wearing sunscreen while in the sun to prevent skin cancer we end up with less available Vitamin D (contact with the sun activates our own bodies manufacture of Vitamin D).
Calcium and Vitamin D - and Breast Cancer
In 1993 and 1995 a total of over 30,000 women over 45 years of age participated in The Women's Health Study, a large-scale, long term study involving thousands of women across the United States. The participants provided medical history, lifestyle factors (such as smoking or exercise), and answered a detailed dietary questionnaire (Arch Intern Med 2007;167(10):1050-1059).
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.
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