Sunshine, Vitamin D, and Death by Scientific Consensus

In the 1890s, the crippling bone-softening children's disease rickets was still widespread in northern states, which has more pollution and a thicker ozone layer than the northwest. Ozone blocks the invisible component of sunshine, ultraviolet B, which produces vitamin D in the skin.

In the early 1900s, it was demonstrated that summer midday sunshine prevented rickets. As a result, there was an effort to educate the public and nearly everybody learned that a little sunshine was good for you. If you're of baby boom age, your mother undoubtedly told you to “go outside and get some sun.” That's why.

Ironically, the beginning of the end of this attitude came in 1923 when a means of producing dietary D was found. UW-Madison biochemistry professor Harry Steenbock discovered that the vitamin D content of milk and other organic substances could be increased with ultraviolet (UV) irradiation. This led to the widespread enrichment of milk and the near elimination of rickets. Slowly, the perception of sunshine as healthy began to fade.

For the most part, scientists lost interest in the biological role of sunshine for higher animals. Dr. Michael Holick was the notable exception. For the last thirty years, Holick has been gathering data, doing research, and studying the role of sunshine and vitamin D.

As a graduate student, Holick first identified the major circulating form of vitamin D in human blood as 25-hydroxyvitamin D. He then isolated and identified the active form of vitamin D as 1,25-dihydroxyvitamin D. He determined the mechanism for how vitamin D is synthesized in the skin, and demonstrated the effects of aging, obesity, latitude, seasonal change, sunscreen use, skin pigmentation, and clothing on this vital cutaneous process. Too often, however, he was treated like a climate change skeptic at an Al Gore fundraiser.

Thanks to his work, we now know that D is not actually a vitamin. It is prohormone, meaning that it is a precursor form of a steroid hormone created by conversion in various organs. This active hormone acts to regulate multiple important biological functions. Every single cell in the body has a D receptor, even stem cells.

When I asked Holick what the source of his epiphany was so long ago, he explained that it was the simple fact that D is a critical nutrient without a natural food source. It is so important biologically that early humans could manufacture D even during famines.

For that reason, he questioned the conventional zero-tolerance approach to sun exposure that has held sway with dermatologists since the 1970s. Holick, a professor of dermatology himself, lost his teaching position when he published his findings. When he wrote a book on the subject, he was targeted by a well-funded PR campaign, aimed at debunking him, by the leading dermatological organization. Supposedly objective journals, including the New England Journal of Medicine, refused to publish his exhaustively documented research -- research now accepted as both accurate and pioneering.

About five years ago, the vitamin D climate began to change. Of late, Holick has finally begun to get the recognition he deserves, and he now serves on multiple prestigious boards as well as advises the NIH. He is, incidentally, professor of medicine, physiology and biophysics at the Boston University School of Medicine. Holick is also director of the General Clinical Research Center, the Vitamin D, Skin and Bone Research Laboratory, and the Biologic Effects of Light Research Center at the Boston University Medical Center.

Holick explains that new breakthroughs in other areas have helped him make his case. With advances in computer processing and the decoding of the human genome, for example, it now appears that a remarkable 2000 genes are influenced by vitamin D.

In retrospect, it's odd that the lessons learned from the northern rickets epidemic were not applied sooner to osteomalacia, which is essentially rickets of the aged. In fact, Dr. Holick and others have demonstrated that osteomalacia is preventable and treatable using vitamin D. Osteoporosis, another bone disease, is also related to lack of vitamin D.

That discovery alone is legitimately worthy of a Nobel prize. In Holick's words, though, it is only the tip of the iceberg. Though Holick began documenting the connection between vitamin D insufficiencies or deficiencies thirty years ago, the scientific floodgates have opened in the last year or two. Word of this massive body of evidence has only really begun to permeate the scientific community in the last few months.

Optimal vitamin D serum blood levels, attained through sunlight or supplementation, dramatically reduce the risk of many diseases other than bone maladies. Many of the most serious are ameliorated by an astonishing 50 to 85 percent. These diseases include cancers, from breast and colon to deadly melanoma skin cancers.

Yes, that's right. The really nasty skin cancers can be prevented by getting moderate, sensible sunshine or through vitamin D supplementation. Non-melanoma skin cancers do increase somewhat with sun exposure, especially with sun burns. These skin cancers, however, are relatively benign as they tend not to spread into other parts of the body. They are easily detected and removed because they appear on skin exposed to the sun.