The 2012 edition of The Skin Cancer Foundation Journal features medically reviewed, reader-friendly articles such as tanning, the increasing incidence of skin cancer diagnoses among young women, & the prevalence of melanoma among white males over 50.
expert reviewers found no prevalent vitamin D deficiency in the North American population; they also cau- tioned against seeing vitamin D as a universal panacea, whose baseline amount is good and more is better.16 The IOM reiterated, however, that
vitamin D does protect and strengthen our bones — a fact established long ago. The IOM concluded that many of the other touted health benefits of vitamin D have not been validated to date in large, long-term research studies.17
THE HARVARD STUDY Recently the Harvard School of Public Health (HSPH) published a challenge from the scientific community in response to the IOM report. The HSPH took issue with many of the IOM's conclusions and recommendations.18 First and foremost, it stated that vita- min D deficiency is a prevalent health issue in the population at large. While almost all scientists agree that levels of vitamin D under 20 nanograms (ng, billionths of a gram) per milliliter of blood are associated with poor health and increased risk of developing osteoporosis, diabetes, autoimmune diseases, depression, heart disease and several types of cancer, the authors called the IOM-recommended vitamin D level of 20ng/ml of blood and daily intake of 600 International Units (IU) per day inadequate.19,18 The study authors argue that
while long-term studies are needed, similar results drawn from many pre- liminary independent studies cannot be dismissed. "Taken together," the HSPS report states, "These disparate studies… add up to a powerful conclu- sion: many people do not get enough vitamin D to protect their bones and minimize risk of falling — and taking vitamin D supplements of 1,000 to 2,000 IU per day would be a safe way to do both. This alone is good reason to consider taking a vitamin D supple- ment of 1,000 to 2,000 IU per day, and there is a strong likelihood of other benefits, even if not yet proven."18
In ad-
dition, the International Osteoporosis Foundation recommends that adults over age 60 keep their Vitamin D blood
levels in the 30ng/ml range,20
which
would equal about 800-1,000 IU of vitamin D daily. At the same time, the IOM concern
about the lack of large, long-term vitamin D studies is valid. This is changing. Harvard Medical School and Brigham and Women's Hospital in Boston recently initiated the vitamin D and omega-3 fatty acids trial (VITAL), which should answer some important questions. The five-year VITAL study will track 20,000 men and women across the US and investigate whether taking daily dietary supplements of vitamin D (2,000 IU) or omega-3 fatty
exposure to the sun's ultraviolet B, or UVB, radiation. The amount produced depends on variables such as latitude, skin color, time of day, and season. For instance, it's estimated that for a Caucasian in New York City at 12 PM in the summer, five minutes a day would prompt maximum vitamin D production.21,22
However, it's important
to note that after this maximum has been reached, further UVB radia- tion exposure will not increase the amount of vitamin D in the body, but will instead have the opposite effect, causing vitamin D to break down into inactive compounds.23,24 So, we are faced with two related
The information highlighted in the press is not necessarily scientifically proven and occasionally blatantly misleading.
problems: we know that UV light can lead to skin cancer, premature aging and irregular pigmentation; we also know that most people living in non-equatorial, urban environments have insufficient vitamin D levels. But this quandary is not impossible to solve: the safest course of action is to maintain an adequate blood level of vitamin D through diet and nutritional supplementation, and not via sun exposure.25,26,18
acids reduces the risk for developing cancer, heart disease, and stroke in people who do not have a prior history of these illnesses.18
ALREADY PROVEN: THE UV-SKIN CANCER CONNECTION The results of this study are still pend- ing, but what is well established is the danger of sun exposure. The World Health Organization has declared that ultraviolet (UV) light from the sun or tanning beds is a human carcinogen (cancer-causing agent). Nonetheless, some proponents of increased vita- min D intake endorse it as the best way to obtain the nutrient. The body can indeed manufacture a limited amount of vitamin D in response to
EDITOR'S NOTE: The Skin Cancer Foundation advises children and adults under age 70 who regularly practice sun protection to obtain the recommended daily 600 IU (international units) of vitamin D a day from food sources such as oily fish, fortified dairy products and cereals, and supplements. Four hundred IU are appropriate for infants under 12 months old, and 800 IU are recommended for people 70 and older. For people who are deficient in vitamin D, it is acceptable to take 1,000 to 2,000 IU doses daily for limited periods.
MARAL SKELSEY, MD, is Director of the Dermatologic Surgery Center of Washington, in Washington, DC. Director of the Mohs Surgery Unit and Clinical Assistant Professor of Dermatology at Georgetown University, she is a member of The Skin Cancer Foundation's Amonette Circle. Her research examines the relationship of Vitamin D to skin cancer.
References available on p.96. 45