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In Brief
- Vitamin D, long associated only with its role in bone formation, is actually active throughout the human body, powerfully influencing immune system responses and cell defenses.
- It can be obtained from food or manufactured by human skin exposed to sunlight. Measures of vitamin D levels show, however, that many people have too little of it circulating in their blood to protect health.
- Clear associations between low vitamin D levels and cancers, autoimmunity, infectious diseases and other conditions suggest that current daily intake recommendations for this critical nutrient need revision.
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It was called the sunshine cure, and in the early 20th century, before the era of antibiotics, it was the only effective therapy for tuberculosis known. No one knew why it worked, just that TB patients sent to rest in sunny locales were often restored to health. The same “treatment” had been discovered in 1822 for another historic scourge, rickets—a deforming childhood condition caused by an inability to make hardened bone. Rickets had been on the rise in 18th- and 19th-century Europe, coinciding with industrialization and the movement of people from the countryside to the polluted cities, when a Warsaw doctor observed that the problem was relatively rare in rural Polish children. He began experimenting with city children and found that he could cure their rickets with exposure to sunshine alone.
By 1824 German scientists found that cod-liver oil also had excellent antirickets properties, although that treatment did not catch on widely, in part because the possibility that a food might contain unseen micronutrients important to health was not yet understood by doctors. And nearly a century would pass before scientists made the connection between such dietary cures for rickets and the beneficial effects of sunshine. Early 20th-century researchers showed that irradiated skin, when fed to rats with artificially induced rickets, had the same curative properties as cod-liver oil. The critical common element in the skin and the oil was finally identified in 1922 and dubbed vitamin D. By then the idea of “vital amines,” or vitamins, was a popular new scientific topic, and subsequent research into the functions of vitamin D in the body was very much shaped by D’s image as one of those essential micronutrients that humans can obtain only from food.
This article was originally published with the title Cell Defenses and the Sunshine Vitamin.
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10 Comments
Add CommentI'm a regular subscriber to your magazine. I've destroyed my Nov. 2007 copy. How may I aquire a copy of this vitamin d article?
Reply | Report Abuse | Link to thisOtto M. Homer
P.O.Box 1411
Lake Ozark, Mo. 65049
this article is very interesting. science is so very fascinating! i have learned something new and i appreciate that! now... why do people think science is geeky? it rox my freakin sox!!!!!!! lol, i am supery dupery the cooliest! i love cole sprouse but he is outta my league... I AM A DORK!!!!
Reply | Report Abuse | Link to thisscience is fascinating... I AM ADORK!! lol
Reply | Report Abuse | Link to thisScience does rock and you can get a copy of this article via Scientific American Digital:
Reply | Report Abuse | Link to this[url http://www.sciamdigital.com/]http://www.sciamdigital.com/[/url]
Well done. All of my patients will be referred to this clear and thorough review of Vitamin D.
Reply | Report Abuse | Link to thisDr. Tom O'Bryan
Great Article: How can we get this message out, this could prevent so much illness.
Reply | Report Abuse | Link to thisFascinating article! I had been following some of the D research for a while but this brings it together in a cogent way. The only point omitted is that several common medications, including anticonvulsants and prednisone, tend to drastically deplete Vitamin D absorption, and that those on these meds should not only have regular tests of Vitamin D levels, but also take additional supplements to offset the medication's effects.
Reply | Report Abuse | Link to thisI believe there is also another important point to consider...Vitamin D is part of the A,D,E,K group and is fat soluble. We are told by nutritional experts that this group requires some "fat" taken along with them for proper absorbtion. I wrote a short article on this from much reading on the subject.
Reply | Report Abuse | Link to thishttp://www.healthmad.com/Nutrition/Fat-Free-Diets-Can-be-Downright-Dangerous.55154
Fat Free Diets Can be Downright Dangerous
I'll bet Lance Armstrong, who may have learned about D during his recovery from cancer, found that a side benefit of "D sufficiency" is stronger muscles. Hence he could pedal sans performance improving drugs and still come out the winner. For info on studies on D and muscle efficiency, visit http://www.vitamindcouncil.org/newsletter/2006-apr.shtml
Reply | Report Abuse | Link to thisThis article didn't touch on mental functioning, but others have shown how crucial D is, and brain cells are loaded with D receptors. Since people with more skin color need as much as 12 times more sun time to make enough D, this is a clue to the mysterious Achievement Gap This is the stubborn difference in test scores between Asian/white students and black/Hispanic students---which even persists into middle class schools where, presumably, students have more support at home and adequate diets. For more, see goodschoolfood.org.
In other words, D levels, which are typically lower in students of color, could be as important as any other factor. In the district where I teach, improvements in class size, teacher training, and curricula have not closed that gap. This theory is backed up by the results at schools where sunlight is used in classrooms for lighting; kids do 20% better on tests and have 20% fewer cavities. http://www.greenteacher.com/articles/60rkool.html
In short, what do high school kids want? To pass their classes and to succeed in athletics. D can help with both.
I've tried 20 mcg Vitamin D (400% daily advised dose) daily since I read the article and it seems to protect me from 3 times a year my regular colds. I actually started while I had a cold and although the cold lasted 5 days the regular aftermath was absent. this ensured me that I was on to something. Thanks for this excellent article!
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