By the Blouin News Science & Health staff

Vitamin D deficiency increases risk of bone fracture

by in Medicine.

An atmospheric phenomenon known as a "sun dog" is seen in La Paz June 26, 2013. The rare halo around the sun is caused by the refraction of sunlight by small ice crystal in the atmosphere. REUTERS/Ulises Rodriguez (EL SALVADOR - Tags: ENVIRONMENT SOCIETY)

A “sun dog” is seen in La Paz. REUTERS/Ulises Rodriguez

Not getting enough Vitamin D can cause your bones to age prematurely, significantly increasing the risk of fracture by up to 31%, according to a study published last week in the journal Science Translational Medicine.

The body produces Vitamin D when the sun’s ultraviolet rays penetrate the skin. One of the vitamin’s functions is to help the intestines absorb calcium, which is important for maintaining strong, healthy bones. Vitamin D deficiency can lead to diseases like osteoperosis, when bones lose their density and break easily, and rickets, when the bones soften and bend.

Scientists previously attributed the increased likelihood of fracture in Vitamin D deficient patients to the inability of their bones to mineralize, or harden, properly, but the new research revealed deeper structural changes that undermined their bones’ integrity. The study was lead by Dr. Bjorn Busse of the University Medical Center of Hamburg in Germany.

Researchers took bone samples from 30 people aged 57 to 60 who had died of natural or accidental causes but were otherwise healthy at their time of death. Half of the subjects were Vitamin D deficient.

Using various advanced measurement techniques, including CT scans and bone mineral density distribution analyses, the researchers found that while the bones of subjects with low levels of Vitamin D had a layer of less mineralized bone around the surface, underneath the bone was denser and more mineralized than normal. They determined that this was due to impediments in the functioning of osteoblasts and osteoclasts, the cells that direct the formation of new bone. As the older bone continued to mineralize in Vitamin D deficient patients, the osteoclasts were unable to move through the bone and reach the outer layer, which remained unmineralized.

About 40 million people have osteoperosis or low bone mass, according to the National Institute of Health. The NIH recommends that children and adults get 600 units of Vitamin D each day, the equivalent of 10-15 minutes of sunlight. Adults 71 and older should get about 800 units of Vitamin D each day.