Dermatologists must be aware that their recommendations to avoid sun exposure may be inadvertently creating other health problems. Image courtesy of thanker212.

UV radiation from sun exposure is associated with an increased risk of skin cancer. But too little sun can result in severe vitamin D deficiency, a common condition that is also linked to cancer. Additionally, low vitamin D is associated with autoimmune disorders and several other diseases.

New research from Stanford University suggests that dermatologists must be aware that their recommendations to avoid sun exposure, particularly for patients at high risk of skin cancer, may be inadvertently creating other health problems.

The study was published in the October issue of the Archives of Dermatology and examined vitamin D levels in patients with a genetic pre-disposition to sun-related skin cancer called basal cell nevus syndrome (BCNS). Vitamin D levels of BCNS patients were significantly lower than control subjects matched for age, skin tone and geographic location.

The best predictors of vitamin D levels in patients were the time of year—levels were higher in the summer—and body mass index. Obesity is known to be linked to vitamin D deficiency since fat soluble vitamin D is more easily sequestered in extraneous body fat.

Lead researcher Dr. Jean Tang says, “Our study shows that skin cancer patients who vigilantly photoprotect are three times at risk for vitamin D deficiency.”

According to Tang, while it is important to warn patients of the dangers of excessive sun exposure, it is equally important to remind them that vitamin D supplementation should be part of their daily regimen to ensure adequate blood levels. The authors of the study recommend at least 1000IU of vitamin D for patients, particularly in winter months.

The research is also relevant to the general population, particularly those who are overweight, have an indoor lifestyle or live north of 35° latitude, all risk factors for vitamin D deficiency. Ideal vitamin D levels should be above 30 ng/mL.

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A look into the science of skin.

In an article this week in the New York Times, brainpower was correlated with the complexity of nerve synapses. Leading researcher Dr. Grant, who has studied the interconnectedness of neurons, likened this connection to technology; "From the evolutionary perspective, the big brains of vertebrates not only have more synapses and neurons, but each of these synapses is more powerful – vertebrates have big Internets with big computers and invertebrates have small Internets with small computers." The brain has been made analogous to a computer before in order to study evolutionary adaptation. However, the brain was not the organ being studied, rather it was human skin.

Have you ever wondered why we have hair only on the tops of our heads and the rest of our skin is relatively bare? Why does our skin come in so many pigmentations? And why does our skin sweat? Dr. Nina Jablonski kept asking why and attributes these adaptations to the need to keep our brain cool. I first heard Dr. Nina Jablonski speak about her most recent book, Skin: A Natural History, in early 2007. I was absolutely enthralled and two hours raced by as she articulated her fascination with skin. Dr. Jablonski divulged into why our skin appears and acts the way it does from an evolutionary standpoint. Her findings showed that about two million years ago our ancestors were running long distances in Africa under the heat of the equatorial sun. To keep their brains cool, sweat glands became more prominent. This in turn let brain size expand and evolve. In the fossil record, it shows after this increase in brain size, Homo sapiens left Africa to migrate into Mainland China.

Skin:A Natural History

So skin was an evolutionary adaptation to keep our large brains cool and working effectively. Skin color, Dr. Jablonski surmised, was what regulated our body's reaction to the sun and its rays. Dark skin evolved to protect the body of those of our ancestors close to the equator. Those ancestors further away evolved light skin in order to take in Vitamin D in less sunny climates. After her talk about Rosacea, which is a condition of constant blushing found in Eastern European nationalities, I asked Dr. Jablonski why. She told me this might have been attributed to ancestors of light skin being overly bundled and getting over-heated. It might have been an adaptation to release heat and cool the brain from the only exposed skin.

In her lecture, Dr. Jablonski did not stop with touching upon evolutionary adaptations, she also delved into how we associate and identify through our skin. We decorate our skin, clothe it, paint it, tattoo it, scar and pierce it. She elucidated skin as an intimate connection with the world as well as our presentation of individuality. Skin: A Natural History and Dr. Nina Jablonski have gained national recognition. She was even invited as a guest on the Colbert Report to talk about her findings. It is rumored that she is following up Skin with more in-depth research. Until then, this is an outstanding look at a very under-appreciated organ, one that might have made the complex nuances of our brain and its synapses possible.

Watch Dr. Nina Jablonski on The Colbert Report:

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