The Sun:

The Body's Natural Source of Vitamin D

How Our Bodies Produce Vitamin D

  • After exposure to ultraviolet light in the UV-B spectrum, 7-dehydrocholesterol in the skin is converted into Previtamin D3

  • Previtamin D3 binds to a protein, which is transported to the liver, where it undergoes a first transformation

  • A second transformation occurs in the kidneys and other tissues of the body

Many Factors Affect Vitamin D Production

  • Time spent outdoors and skin pigmentation are the two most important determinants of the rate/amount the natural Vitamin D synthesis

  • Lighter pigmented skin – full-body exposure during summer months for 10 to 15 minutes  generates between 10,000 and 20,000 IU of vitamin D3 within 24 hour

      • Darker pigmented skin – requires 5 to 10 times more exposure to generate similar amounts of vitamin D3.

      • Other factors impact the amount of Vitamin D produced by the body 

        • Amount of skin exposed; body mass

        • Environmental conditions – latitude, season, cloud cover, air pollution

        • UV protection measures – clothing, sunscreens