Vitamin D: A double-edged sword in the fight against osteoporosis?

Vitamin D is renowned for its role in creating strong bones and is a key regulator of serum calcium levels. Calcium is primarily obtained through diet and absorbed through the intestine and into the blood stream. In addition to building bone, calcium is required for a variety of important physiological processes. Vitamin D, which is detected by receptors in bone and intestinal cells, regulates the level of calcium in the blood stream and determines how much should be stored in the skeleton. Several recent clinical trials have examined the effects of vitamin D supplements on the prevention of bone fractures in the elderly; however, the results of these trials have not offered a consensus on the efficacy of these supplements.

In this month's issue of JCI, Dr. Geert Carmeliet and colleagues at the University of Leuven in Leuven, Belgium, investigated how vitamin D affects the skeleton when serum calcium levels are depleted. Using mice that lack the intestinal vitamin D receptor, the researchers showed that the mice still had normal serum calcium levels even when given a low-calcium diet. Additional experiments demonstrated that vitamin D stimulated to produce factors that removed calcium from bone in a process known as in order to maintain normal serum calcium levels. Thus, while vitamin D is important for maintaining serum calcium levels, it can also promote .

In an accompanying article, Dr. Cathleen Colón-Emeric and Dr. Kenneth Lyles of Duke University Medical Center in Durham, North Carolina, discuss the clinical implications of this investigation as well as how these findings may explain clinical trial results where vitamin D supplements failed to prevent fractures in elderly patients and, in some cases, were correlated with increased fracture rates.

More information: Normocalcemia is maintained in mice under conditions of calcium malabsorption by vitamin D–induced inhibition of bone mineralization, Journal of Clinical Investigation (2012).

add to favorites email to friend print save as pdf

Related Stories

Vitamin D and calcium interplay explored

Mar 12, 2010

Increasing calcium intake is a common -- yet not always successful -- strategy for reducing bone fractures. But a study supported in part by the Agricultural Research Service (ARS) underscores the importance of vitamin D ...

Study strengthens case for daily calcium pill

Aug 27, 2007

A landmark study by University of Western Sydney researchers has found people over 50 who take calcium supplements suffer fewer fractures and enjoy a better quality of life.

Vitamin D deficiency high among trauma patients

Feb 07, 2012

New research presented at the 2012 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS) found that 77 percent of trauma patients had deficient or insufficient levels of vitamin D.

Recommended for you

Study reveals state of crisis in Canadian foster care system

18 hours ago

A new study of foster care in Canada led by a researcher at Western University reveals a shrinking number of foster care providers are available across the country to care for a growing number of children with increasingly ...

Researchers prove the benefits of persimmons for diet

20 hours ago

Alba Mir and Ana Domingo, researchers from the Department of Analytical Chemistry of the University of Valencia, under the supervision of professors Miguel de la Guardia and Maria Luisa Cervera, from the same department, ...

Hand blenders used for cooking can emit persistent chemicals

20 hours ago

Eight out of twelve tested models of hand blenders are leaking chlorinated paraffins when used according to the suppliers' instructions. This is revealed in a report from Stockholm University where researchers analyzed a ...

User comments

Adjust slider to filter visible comments by rank

Display comments: newest first

spiritosl
4 / 5 (1) Apr 25, 2012
The headline "Vitamin D: A double-edged sword in the fight against osteoporosis?" is definitely wrong.
If you deplete calcium in the food then the only source of Ca is the bones and the vitamin D3 at higher concentrations improves the stability of Ca+ level in the blood. The only source of Ca to maintain Ca level in blood is the Ca in the skeleton. Then you get osteoporosis in the poor malnutried animal (and humans)
Seems to be an odd experiment that doesn't prove anything IRL.
Don't forget that vitamin D3 is essential and at the high latitude where I live (61ºN) sun is a good but insufficiennt source of vitamin D3 but in a short summer. Thus I have 50 000 IU vitamin D3 per week to stay healthy. There are reports showing 100 000 IU of vitamin D per day for a year is nontoxic. So have enough (at least 5 000 IU/day) vitamin D3!
dutchman
not rated yet Apr 25, 2012
According to recent research at various medical universities, vitamin D3 plays a crucial role in the prevention of various types of CANCER. This was broadcast in a series of presentation on the University of California TV (UCTV.edu) The recommendation was 10,000 IU per day, and NO level of toxicity has been found. 10,000 IU per day for life may wipe out cancer altogether!

I think this is at least as important (if not more so) than osteoporosis.