From Dr. Mercola:
Sunlight: we all feel better when we’re exposed to it, but do you know why? Dr. Michael F. Holick, a foremost expert on vitamin D with an impressive list of credentials, is just the right person to explain the healing power of sunlight.
His academic credentials include chief of Endocrinology, Diabetes, and Nutrition at Boston City Hospital and Boston University Medical Center from 1987 until 2000.
He’s currently the director of Bone Health Care Clinic, and a professor of Medicine, Physiology, and Biophysics at Boston University Medical Center. He’s also the director of the Boston University Heliotherapy, Light, and Skin research lab.
While enrolled at the University of Wisconsin, he worked with Dr. Hector DeLuca on vitamin D, and ended up getting his M.S. by identifying 25-hydroxyvitamin D3 as the major circulating form of vitamin D in the human blood stream.
This is the form you want to measure to determine your vitamin D status.
For his Ph.D. he identified the biologically active form of vitamin D as 1,25-dihydroxyfitamin D3. As a postdoctoral fellow he participated in the first chemical synthesis of 1,25-dihydroxyvitamin D3 that was used to treat bone disease in kidney failure patients.
Later, he became interested in understanding how vitamin D is made in the skin. So he worked out methods to determine how factors such as time of day, season, latitude, skin pigmentation, and obesity influence this cutaneous process.
“I also realized that the skin had vitamin D receptors,” he says. “What that means is that the active form of vitamin D was working in the skin, and I wanted to know why. It turns out that active vitamin D inhibits skin cell growth and modulates it in a very important way.
I then realized that maybe you could use it to treat a very common hyperproliferative skin disorder: psoriasis. I basically introduced the concept, in the mid-’80s, of topically applying active vitamin D to treat psoriasis …
I’ve also done lots of other studies looking at how vitamin D is absorbed by the body and its impact on your health.”
Sunlight for Your Health
When you’re exposed to sunlight, all of the sun’s energy is hitting your skin. Over the past 40 years, dermatologists have promulgated the idea that you should never be exposed to direct sunlight because it will damage your skin and cause skin cancer.
What they fail to appreciate is that when you’re exposed to sunlight, many important biological processes occur in your skin. This is distinct from swallowing oral vitamin D.
While taking an oral vitamin D supplement will improve your vitamin D status, you forgo the benefits sunlight offers beyond vitamin D production.
Unfortunately, the vast majority of people have no alternative in the winter months. But in spring, summer, and fall, it’s wise to take advantage of sensible sun exposure, using the app “dminder.info” which Dr. Holick discusses in his PowerPoint presentation, “Sunlight for Your Health.”
Not only does sunlight make vitamin D in your