A vitamin D deficiency occurs when the level of vitamin D in your body is too low. Vitamin D helps the body use calcium from our diet which is essential for us as humans to maintain bone strength. If you feel you might be experiencing symptoms of a vitamin D deficiency, it is important to get tested and treated because it can eventually cause your bones to become thin, brittle or misshapen. The only way to confirm that you are suffering from a vitamin D deficiency is to get a blood test to test your vitamin D levels. In the meantime, if you are experiencing any of the following signs or symptoms, you should get tested sooner rather than later.