Study: Vitamin D lowers bone-fracture risk only at high doses
July 4th, 2012
05:01 PM ET

Study: Vitamin D lowers bone-fracture risk only at high doses

If you're wondering whether to take a vitamin D supplement to keep your bones healthy, it's understandable if you - and even your doctor - are at a loss.

Vitamin D is essential for bone health, but the research on supplements has been inconsistent. Some studies have concluded that vitamin D supplements can lower the risk of bone fractures, while others suggest the pills provide little to no benefit.

The latest study on the topic, published today in the New England Journal of Medicine, may help clear up some of the confusion.

The study, a re-analysis of data from 11 clinical trials comprising more than 31,000 people age 65 and older, found that vitamin D supplements - which are often combined with calcium supplements - are associated with a lower risk of bone fracture only when taken at high doses.

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Overall, 4% of the study participants fractured their hip during the studies, and 12% fractured a bone elsewhere in their body (not including vertebrae).

Taking less than about 800 international units (IU) of vitamin D per day, with or without calcium, had no effect on bone-fracture risk when compared with taking a placebo or a calcium supplement alone. Taking 800 IU or more, by contrast, decreased the risk of hip fracture by 30% and the risk of other bone fractures by 14%.

"A 30% reduction in hip fracture with an inexpensive and safe intervention such as vitamin D has enormous public health implications," says lead author Dr. Heike Bischoff-Ferrari, director of the Center on Aging and Mobility at the University of Zurich, in Switzerland.

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The new findings go a long way toward explaining why past studies on vitamin D and fracture risk have produced conflicting results, says Dr. Robert P. Heaney, an osteoporosis researcher and professor of endocrinology at Creighton University, in Omaha, Nebraska.

"All of the problems with previous studies come from a very modest dose of vitamin D," says Heaney, who wrote an editorial that accompanies the study. "If you don't give [study participants] enough of the vitamin D, then you won't see an effect."

Should people over age 65 start taking at least 800 IU of vitamin D each day? Not necessarily. Although Bischoff-Ferrari and her colleagues suggest a daily supplement may be beneficial, other groups have stopped short of making the same recommendation.

The Institute of Medicine, an influential nonprofit organization, recommends that people in their 70s or older consume at least 800 IU of vitamin D per day. But that vitamin D can come from fortified foods - not to mention sunlight, which naturally spurs the body to produce the vitamin.

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And in June, the U.S. Preventive Services Task Force (USPSTF), a panel of independent experts that advises the federal government on preventive care, issued draft guidelines saying there is too little evidence to recommend vitamin D supplements for the prevention of bone fractures.

To complicate matters further, the dose needed to promote bone health appears to vary from person to person depending on his or her baseline vitamin D levels, Heaney says.

Bischoff-Ferrari says her team's analysis - "the best evidence we have today," she says - may merit a revision to the USPSTF recommendations, which have yet to be finalized and are open to public comment through July 12.

"I do think that our results can support a change in these recommendations for seniors," she says.

Copyright Health Magazine 2011

soundoff (11 Responses)
  1. Ragini Sharma

    I agree with you, Vitamin D is very imp for our body..thank you for sharing such nice info here. Vitamin D is very important for ladies in their growing age.
    |joint repalcement India

    July 5, 2012 at 03:02 | Report abuse | Reply
  2. CLS88

    "High dose" vitamin D?

    In reality less than 2000 i.u. daily is practically meaningless.

    In NO WAY does 400-800 i.u. reflect evolutionary levels of vitamin D produced daily.

    Humans made/make LOTS of vitamin D when outdoors. Prior to the last 40 years (and certainly prior to the Industrial Revolution) we were exposed to the sun 10-20 X more than current.

    "Vitamin" D is the human body's most potent steroid hormone, when metabolized. No other natural molecule does more to maintain, and repair, the human genome.

    July 5, 2012 at 09:23 | Report abuse | Reply
  3. KS

    Vitamin D is definitely incredibly important for bone health. I've been hearing a lot about vitamin D supplementation lately- I recently read a blog post on the topic that I thought was interesting. It discussed a recent study suggesting that lower levels of vitamin D may be associated with an increased risk for disability. It's on the Natural Standard blog: http://blog.naturalstandard.com/natural_standard_blog/2012/06/low-vitamin-d-levels-linked-to-increased-disability-risk.html

    July 5, 2012 at 12:27 | Report abuse | Reply
  4. Ifeco

    What about Osteomalacia?

    July 5, 2012 at 15:38 | Report abuse | Reply
  5. yohana14

    This is a very important fact! I didn't know it aids in bone health. Vitamin D is one of the most useful vitamins but under-recognized my mostly young adults. Thanks for sharing!

    July 5, 2012 at 22:11 | Report abuse | Reply
  6. linda davis

    I have had 3 test for vitamin D.. I have to take 10,000 units a day in order to keep my levels in the normal range.. It is inexpensive and 2 small pills..if it works it is worth it.

    July 6, 2012 at 08:01 | Report abuse | Reply
  7. missy

    just sitting in the sun 15 min a day can help with you vitamin D.

    July 6, 2012 at 13:33 | Report abuse | Reply
  8. jammies

    Good grief – 800 units a day of D3 is such a tiny dose it's hardly worth taking. Get your D3 levels tested and dose with a good quality oil based D3 supplement until you are in the upper half of the "normal" range. I take 2000-5000 units a day. Also take some Vitamin K2 (not K1) with your D3. This combo is perfect for strengthening bones.

    July 7, 2012 at 00:37 | Report abuse | Reply
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    July 31, 2012 at 20:52 | Report abuse | Reply
  10. Nicole

    Great post! We all know that calcium and vitamin D help to build strong bones, but the question everyone is asking is "how much of this stuff do I actually need to get a real benefit from it"? I remember seeing a debate on the use of Vitamin D in the prevention of fractures, and it was extremely difficult for the side arguing against it since there were no strong studies that were published indicating that sometimes Vitamin D may not always be helpful. There was also little data on the actual side effects of Vitamin D. A great way to read about the studies and potential risks and benefits of Vitamin D is to go on the Natural Standard website- the service provides evidence based recommendations for the various aliments Vitamin D is commonly used for! Note: These postings are my own and do not necessarily represent Natural Standard’s positions, strategies or opinions.

    August 30, 2012 at 17:39 | Report abuse | Reply
  11. Nadrich & Cohen LLP

    This is a great post! Very informative!

    Claire @ http://boneinjurycenter.jimdo.com/

    November 14, 2012 at 11:27 | Report abuse | Reply

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