Use

• Vitamin D maintains normal blood levels of blood and phosphorous. This helps promote calcium absorption in the stomach and normal mineralization of bones, and thus is vital in healthy bone growth and preventing bones from becoming thin or misshapen. In addition, Vitamin D aids the immune system.
  
  

Deficiency

• Without enough Vitamin D, the bones in the body are at risk of becoming brittle or misshapen. For children, a deficiency can cause rickets, and for adults it can cause osteomalacia, as well as leading to a development of osteoporosis. In addition, without enough Vitamin D the immune system can become dysfunctional, leading to autoimmune disorders, or raise the risk of multiple types of cancer. It can also lead to muscle weakness or deterioration.
  
  

Sources

• In order to receive enough Vitamin D, an important factor is daily exposure to sunlight, which encourages the development of Vitamin D. In non-fortified foods, the flesh of fish, fish oil, beef liver, cheese or mushrooms contain some Vitamin D. However, in foods fortified with Vitamin D, milk, certain cereals or orange juice contain healthy amounts.