Vitamin D is essential for the development and maintenance of bone, both for its role in assisting calcium absorption from food in the intestine, and for ensuring the correct renewal and mineralization of bone tissue. People who have decreased vitamin D serum levels run the risk of first acquiring osteopenia. If the osteopenia is not treated this may lead to osteoporosis (the diagnostic difference between osteopenia and osteoporosis is the measured decrease of bone mineral density) due to the decrease in calcium absorption, thus increasing their risk of bone fractures.
