How does vitamin D help the body?
The most conclusive information about the role of vitamin D comes from evidence in bone and teeth development. Vitamin D helps the body use calcium and phosphorus to build and maintain healthy bones and teeth. It helps our bodies absorb calcium/phosphorus from the food that we eat. Vitamin D works hand in hand with other nutrients for bone health and is essential for calcium uptake.
Bones, teeth, and skeletal muscles
Vitamin D promotes the growth and maintenance of healthy bones and teeth. Vitamin D is important in supporting a healthy skeletal system by:
- Decreasing the risk of developing soft bones, deformity, and fractures known as rickets in children and osteomalacia in adults
- Helping to maintain healthy bones in adulthood. Osteoporosis involves reduced bone mineral density, and is characterized by broken bones (especially hip, wrists and spine)
- Allowing the absorption of calcium and phosphorous to build strong teeth, especially the enamel which is actually the hardest substance in the body
- Muscles contain vitamin D receptors. Muscle strength and function have been linked to vitamin D[i]
What about vitamin D in other areas?
Research suggests that there could be an association of vitamin D with other functions in the body. There are many different types of tissues in the body that contain vitamin D receptors (VDRs) and would therefore have the ability to respond to circulating vitamin D in the body[ii].
There are different opinions about the importance of vitamin D as research continues to look at the extra-skeletal functions of vitamin D. More evidence is needed to say definitively what role vitamin D plays throughout the body. Studies continue to look at relationships with vitamin D and immune regulation, promotion of cell differentiation, and regulating cell growth. Areas of active vitamin D research include pregnancy, cardiovascular, and brain function.
 Bischoff-Ferrari HA, Giovannucci E, Willett WC, Dietrich T, Dawson-Hughes B. Estimation of optimal serum concentrations of 25-hydroxyvitamin D for multiple health outcomes. Am J Clin Nutr 2006;84:18-28.
 Boullion R., Okamura, WH, Norman AW. Structure-function relationship in the vitamin D endocrine system. Endocr rev 1995;16:200-57.