The American Academy of Dermatology still recommends vitamin D come from a healthy diet and supplements, not from unprotected skin exposure to ultraviolet radiation, according to their newly updated position statement.
The update comes in response to the Institute of Medicine's (IOM) recent review of existing data on possible roles for vitamin D status in certain types of cancers, and neurologic, infectious, autoimmune, and cardiovascular diseases. In the report, the IOM called existing evidence "inconsistent, inconclusive as to causality, and insufficient to inform nutritional requirement." However, the organization found that the evidence does support a role for vitamin D in bone health.
Dr. William D. James
"The IOM's review of the scientific evidence about vitamin D supports the Academy's long-standing recommendation on safe ways to get this important vitamin – through a healthy diet which incorporates foods naturally rich in vitamin D, vitamin D–fortified foods and beverages, and vitamin D supplements," AAD president Dr. William D. James noted in a statement.
In particular, the statement reinforces the idea that unprotected UV exposure to the sun or indoor tanning devices is a known risk factor for the development of skin cancer. There is no scientifically validated, safe threshold level of UV exposure from the sun or indoor tanning devices that allows for maximal vitamin D synthesis without increasing skin cancer risk.
The Academy recommends a comprehensive photoprotective regimen, including the regular and proper use of a broad-spectrum sunscreen to protect against skin cancer.
The statement also includes new IOM Recommended Dietary Allowances (RDA) for calcium and vitamin D intake. Of note, these age-based values were derived assuming minimal or no sun exposure, given inconsistent contributions of sunlight to vitamin D in the population and also because of the risk of cancer associated with sun exposure.
Adequate vitamin D was defined by the IOM as blood levels of at least 20 ng/mL as measured in the United States (50 nmol/L as measured in Canada).
Physicians should discuss options for obtaining sufficient dietary or supplementary sources of vitamin D with patients having concerned about their vitamin D levels.