Vitamin D Intake vs. Sun Exposure

Known as the "sunshine vitamin", the body’s ability to manufacture Vitamin D naturally occurs after being exposed to the sunshine with as little as ten to 15 minutesa day, three times weekly. This exposure is proved to be sufficient to allow the body to create the Vitamin D recommended by the RDA.

Unfortunately, not all individuals will obtain this level of exposure. With an increase in the rate of UV-related skin cancers, we have found the benefit of outdoor activites may not outweight the risks.  Fortunately, because of natural skin cell mutations, it has been determined that the darker one’s skin type may be, the less ultraviolet light the skin is exposed to.  Thus, possibly reducing the risk of skin cancer is darker complextions.  Unfortunately, the dark skin natural skin cell mutations also carry a health risk as darker complexions prevent UV light absorption thus decreasing absorption of Vitamin D.

With dark complexions, the decrease in ultraviolet light provides for a significant impact on calcium absorption and bone growth. From sunlight (ultraviolet light), the body produces an increased production of D(3) which is the vitamin necessary for the body’s calcium absorption and bone growth. Hence, the lack of UV light will result in lack of D(3) production and, thereby, decrease bone growth.

As a result, dietary guidelines recommend an increase of Vitamin D intake by those individuals with darker complexions. This vitamin D intake can be found in fortified Vitamin D foods or in supplements. Supplements are a great addition to the daily adult diet. The current recommendation for Vitamin D intake are 5 ug/d for adults, both male and female, from ages nine to 50 years and 10ug/d for adults, both male and female, ages 50 to 70 years. The equivelant supplement would be 200 IU Vitamin D to equate one 5ug/d dosing. For individuals with darker skin complexions, the intake should be increased to a level no greater than 50ug/d or 2000 IU Vitamin D supplement.