What are the benefits of vitamin D? Perhaps the most vital benefits of vitamin D is the regulation of absorption of calcium and phosphorus,  which in turn facilitates normal immune system function. Getting a sufficient amount of vitamin D is also paramount for normal growth and development of bones and teeth, and many recent studies also correlate an improved resistance against certain diseases. What are the symptoms of vitamin D deficiency? Getting sick often Fatigue and feeling tired constantly Back or bone pain Depression Impaired healing of cuts and other wounds Bone Loss Hair Loss Muscul ..read more