Dermatologists Recommend D from Food & Supplements, not Sun

Regular readers of our newsletter are well aware of the recent research on vitamin D and the calls from experts to increase vitamin D levels among the population. One of the big controversies has been the best way to increase vitamin D levels in people: from supplements and fortified foods, or from the sun? Vitamin D, sometimes called the "sunshine vitamin," can be synthesized in the body after exposure to ultraviolet light from the sun. However, direct exposure to UV light also increases the risk of developing skin cancer.

Now the American Academy of Dermatology (AAD) has weighed in with its opinion. "The American Academy of Dermatology recommends that an adequate amount of vitamin D should be obtained from a healthy diet that includes foods naturally rich in vitamin D, foods/beverages fortified with vitamin D, and/or vitamin D supplements; it should not be obtained from unprotected exposure to ultraviolet (UV) radiation." The AAD goes on to say that "unprotected UV exposure to the sun or indoor tanning devices is a known risk factor for the development of skin cancer. Studies have shown that UV radiation from both the sun and tanning devices can cause oncogenic mutations in skin cells. Use of sunbeds have also been associated with increased risk for melanoma and squamous cell carcinoma." In their position paper, the AAD states that "many epidemiological studies suggest an association between low serum vitamin D levels and increased risk of certain types of cancers, neurologic disease, autoimmune disease and cardiovascular disease," necessitating that individuals talk with their medical professionals to ensure that they are getting enough vitamin D.

The AAD recommended using the Institute of Medicine's (IOM) guidelines for daily intake values for individuals. IOM currently recommends that children and adults up to age 50 should consume 200IU of vitamin D daily. This is half of the US Food and Drug Administration recommendation of 400IU for the same age group. The IOM is currently reviewing their recommended daily intakes to see if these levels should be increased. The IOM last reviewed the Vitamin D intake levels in 1997. New research indicates that these levels should be increased by as much as 5 to 10 times the current levels, with experts from The Johns Hopkins University recommending daily intakes as high as 2000IU daily.

Vitamin D naturally occurs in very few foods; oily cold-water fish, such as salmon, mackerel, and sardines, are good sources of vitamin D. Milk and breakfast cereals are typically fortified in industrialized countries; since 1930s all of the US milk supply has been fortified in a effort to combat rickets. One US cup (8 fl. oz) provides approximately 100IU of Vitamin D3. Vitamin D is available as a dietary supplement in two forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Both are precursors to 25-hydroxyvitamin D, the form of vitamin D that circulates in blood. Vitamin D3 is the form of vitamin D that is produced by the human body when the skin is exposed to sunlight. It is more bioavailable to the human body and more effective at increasing the level of 25-hydroxyvitamin D in the body than vitamin D2. Vitamin D2 requires exposure to sunlight to be converted to D3 before the body can use it.