January 17, 2010
Vitamin D And Calcium Reduce Bone Fractures

Across a wide range of ages both vitamin D and calcium supplements cut the incidence of bone breaks.

(SACRAMENTO, Calif.) — Taking both calcium and vitamin D supplements on a daily basis reduces the risk of bone fractures, regardless of whether a person is young or old, male or female, or has had fractures in the past, a large study of nearly 70,000 patients from throughout the United States and Europe has found.

The study included data published in 2006 from clinical trials conducted at UC Davis in Sacramento as part of the Women’s Health Initiative (WHI). It appears online in this week’s edition of the British Medical Journal.

“What is important about this very large study is that goes a long way toward resolving conflicting evidence about the role of vitamin D, either alone or in combination with calcium, in reducing fractures,” said John Robbins, professor of internal medicine at UC Davis and a co-author of the journal article. “Our WHI research in Sacramento included more than 1,000 healthy, postmenopausal women and concluded that taking calcium and vitamin D together helped them preserve bone health and prevent fractures. This latest analysis, because it incorporates so many more people, really confirms our earlier conclusions.”

Bottom line: Yes, they both help.

Vitamin D alone is not as effective as when combined with calcium.

“This study supports a growing consensus that combined calcium and vitamin D is more effective than vitamin D alone in reducing a variety of fractures,” said Robbins. “Interestingly, this combination of supplements benefits both women and men of all ages, which is not something we fully expected to find. We now need to investigate the best dosage, duration and optimal way for people to take it.”

I'm already taking vitamin D every day. But I do not always take calcium. Sounds like calcium is worth taking regularly too. Any thoughts on this?

Share |      Randall Parker, 2010 January 17 10:27 PM 

MRM said at January 18, 2010 9:39 AM:

you should create a vitamin D tag. As a reader of your site, I'd love to see all fo the Vitamin D study papers in one spot. I might be the only one.

random said at January 18, 2010 10:25 AM:

I'm curious how well Calcium & Vitamin D supplements compare against natural sources - food and sunlight.

Michael G.R. said at January 18, 2010 10:43 AM:

I'm taking about 4,000 UI - 6,000 UI of Vitamin D daily (in gelcap format, because it's fat soluble), and there's some calcium in my multivitamin. Wonder if that's enough to give the full effect, though.

Political Junkie said at January 18, 2010 10:58 AM:

Thanks for the interesting article! I have seen anecdotal evidence of that in my own life. When I first started training for marathons I had joint pain, but as I increased the frequency and length of my runs (which should have naturally led to more pain) I started taking D and Cal supplements and the pain subsided. After a few months of training I ran out of supplements and it was about a week before I got more. The pain returned, only to subside again once I started taking them again.

Bill Montgomery said at January 18, 2010 10:58 AM:

Hi, I have Osteoporosis or had it. It has been over two years since the last bone scan. I am 64 and I leg press 450 LB.

Sunlight is best for vitamin D if you live where you can get it and you get 15 minutes a day. My doctor did a study of his patients here in the greater Seattle area and found that 90% were vitamin D deficient. So I take 4000 IU a day along with 1200 mg calcium. My doctor says not to take more than 1500 mg of calcium because it can cause plaque in the arteries I guess.

Bottom line - I got Osteoporosis because of lack of Vitamin D over time. So you guys out there in cloudy parts of the country - pay attention to this!

SteveP said at January 18, 2010 11:17 AM:

I take 4,000IU of D3 daily, 2,000IU along with a gelcap of 600mg of Omega 3 oil with breakfast and 2,000IU along with 1,000mg of vitamin C with supper and take a multivitamin 2 or 3 times a week. I also drink a gallon of whole milk a week. My diet is high in protein, fresh fruits and vegetables, a balance of fats and low in carbs from grains. Other than milk and the occasional beer or glass of wine I only drink water. I get regular, varied, moderate exercise. I don't get flu shots and haven't had a cold or the flu, or missed a day of work from any illness in over 10 years. (I'm 54)

jam said at January 18, 2010 11:38 AM:

4000 IU to 6000 IU is far more than needed according to the recommendations I've seen. I wonder if it is high enough to put you at risk of Vitamin D overdose? I have seen several reports putting the maximum allowable quantity at 2000 IU per day for adults. Most of the articles and studies regarding the benefits of vitamin D I have seen do not warn people about the risks of taking too much or state at what levels the benefits are obtained. The body does not metabolize Vitamin D the same way that it does other vitamins, and over time, taking more than the body needs can lead to an unhealthy build up leading to the the absorption of too much calcium. This can, in turn, result in calcium deposits in the organs and soft tissue. Based on the studies I've seen (many here), I believe that vitamin D deficiency is very unhealthy, and vitamin D supplementation can be a great benefit. But I don't want to take too much. Can you link to any studies regarding proper vitamin D dosage?

GFH said at January 18, 2010 11:59 AM:

All this comment is based on what I have read on the Internet, I would surmise that vitamin D3 while it is produced in our skin from sunshine that is dependent on a particular bandwidth of UV of sufficient intensity. Supposedly, this intensity is achieved daily in the tropics, in the Spring and Summer in temperate regions and about never in the polar regions. Clothes, sun block, interposing glass, etc. can all reduce the intensity or block the UV from reaching the skin. At maximum effect, I have read that essentially whole body for the requisite time and at the required intensity can equate to 10,000 to 20,000 IU dose of vitamin D which is about as much as can be produced because the same UV that produces it can also degrade it so the ?concentration? does keep going up? but reaches an equilibrium point??.

Vitamin D assists in the uptake of calcium from diet up to a maximum value. More D beyond that blood concentration does not really affect uptake. The purpose in taking D with Ca is to try and ensure that Ca absorption is maximized. If one is deficient or has less than a given amount of D, then Ca uptake is less than maximum hence the idea of taking supplements to ensure adequate D. There might be other things D does with respect to getting Ca into bones, but I don't recall any off-hand.

Anyway, I've started taking a 2000 IU D supplement recently. I take 2 x 500 mg Ca that has D (400 IU) and K (40mcg) in each tablet.

LarryD said at January 18, 2010 12:26 PM:

Vitamin D is safe up to 10,000 IU daily, from what I've read. Research indicates that the official MDV is way low, for someone who gets negligible amounts from sun and diet, 4,000 IU is about right.




Jerry from Boston said at January 18, 2010 12:32 PM:


I just read that while the maximum daily allowance from NIH says a maximum of 2,000 mg, it appears we need about 5,000-6,000 mg to get the full benefit of D. We also saw my wife's doctor and asked about Vit K. He said our bodies generate all the Vit K we need and more is not good and can cause damage to our systems. It's why you have a hard time getting separate Vit K supplements OTC and they are in fact usually rolled in with a multi-vitamin at low concentrations.

Maureen said at January 18, 2010 12:33 PM:

The big problem is that, as we get older, we just can't make as much Vitamin D; and some people can't make much Vitamin D even when they're younger. Also, Vitamin D tends to stay in whatever fat you have instead of going into the rest of your body, unless you have a lot of Vitamin D intake. Put that together with the sunlight in some areas just not being enough, and of course you have practically everyone in temperate areas with a deficiency.

As for safety... 10,000 IU is the equivalent of one sunny day's worth of Vitamin D being made by a kid's skin. Vitamin D toxicity doesn't set in for most people unless you take 50,000 IU a day for six months or more. If you have kidney disease or certain other conditions, you have to be a bit more careful about it, though, because your body doesn't deal with Vitamin D normally at that point.

Dr. Holick is your guy for all kinds of Vitamin D studies. He has an incredibly boring-looking but useful website.

willis said at January 18, 2010 1:00 PM:

I take 100,000 IU of vitamin D twice a day and eat the thigh bone of a bull elephant every week. You people are crazy, I don't feel a damn bit better.

isaac said at January 18, 2010 1:54 PM:

jam, yes it is possible to get too much, especially if you're in the lower latitudes and are outside frequently while adding supplements. Regarding prospective studies, most of the dose ranges are in the 400-1000 IU/daily range and looking at fractures. 400 doesn't seem to work while once you get close to 1,000, you begin to see effects. Everything else is either epidemiological correlating blood levels or small trials, which isn't necessarily the same thing. Here's a good starting point which provides the references you seek.


Until longer term, prospective, randomized trials are done with the higher doses, I'd be quite reluctant to take as much as 4,000+ IU/day. It's impossible to overdose on sun vitamin D as it's self limiting, but oral may be another story. We don't know if or at what dose toxicity may begin to show up. While acute effects like arrhythmias may not show up until quite high doses are reached, we don't know about chronic, long term effects. At higher doses, it'd at least be prudent to measure blood levels to see when you're saturated. After all, all the epidemiological data about vitamin C, E and beta carotene showed protection from disease but when the prospective, randomized trials were completed, it looked like they INCREASED cancer. Caveat emptor.

Rob from Texas said at January 18, 2010 6:47 PM:

Vitamin D plus calcium has been used as a standard-of-care comparison (a control group, that is) in studies of new osteoporosis treatments. It's better than nothing, for sure, but has been shown to be less effective than treatments designed specifically for osteoporosis. There are treatments available now that actually stimulate regrowth of lost bone. Forteo is available in the US, and Preotact is available in Europe along with Forteo. If you have osteoporosis, you should look at one of these products or maybe something like Fosamax or Boniva.

Bob Badour said at January 18, 2010 7:57 PM:

Rob from Texas,

That's nice. I don't have osteoporosis. I would like to reduce my chances of bone fracture. What would you recommend?

jam said at January 19, 2010 7:44 AM:

Thanks Isaac. I currently take 1000 IU/day, and I am not going to increase it until there are more studies regarding long term effects from high doses of supplements.

Mthson said at January 20, 2010 12:41 AM:

Does anybody recommend a particular site for ordering supplements?

I figure I might as well order my next batch from Ray Kurzweil's store. I'd expect them to have high quality standards, and I'd rather give business to someone who's cause I support.

toby said at January 30, 2010 6:18 AM:

www.vitaminD3world.com is a good source of information on vitamin D. The site also has links to a neat micro tablet version of vitamin D that is so small you dont even need to swallow it and can just crunch it up in your mouth

KC said at February 24, 2010 10:15 AM:

I found out via yearly tests taken each year at my physical, that I am low on Vitamin D. My dr. prescribed 50,000 IU's Vitamin D prescription pills, twice a week for the next 3 months and then my blood will be tested again. From what I've read, this is fairly standard if you are low. It would take 6 months of 50,000 IU's a day to be a toxic level.

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