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Sun exposure: Benefits beyond D production

Posted on: August 1, 2012   by  Brant Cebulla

Sun exposure: Benefits beyond D production


Some of our readers have requested for more information on the benefits of sun exposure outside of vitamin D production. Fortunately, a review asking this very question was published in the last issue of Dermato Endocrinology by Professors Asta Juzeniene and Johan Moan.

Juzeniene A and Moan J. Beneficial effects of UV radiation other than via vitamin D production. Dermato Endocrinology, 2012.

Here is what we know, sometimes incompletely, about the effects of sun exposure on the human body:

1.  Enhances mood and energy. Generally, a little bit of sun exposure is associated with better mood, while tanners commonly report feeling more relaxed than non-tanners. One study demonstrated that β-endorphins increase after sun exposure, which would explain this association. Three studies found no increase in β-endorphin production after sun exposure, but the authors speculate that the anxiety from a blood draw to check on endorphins would negatively affect endorphin levels.

2.  Treats skin diseases. These diseases include treatment of lupus vulgaris, psoriasis, vitiligo, atopic dermatitis and localized scleroderma. Why phototherapy works in the treatment of these diseases is not completely understood (usually broadband UVB or narrow-band UVB, but sometimes UVA also), researchers do know of some mechanisms during phototherapy. UV radiation reduces the rate of cell proliferation in the skin, activation and proliferation of melanocytes, reduction of T-lymphocytes, and reduction of Langerhans and mast cells.

3.  Relieves pain in fibromyalgia. Sunbathing seems to have potential to reduce pain in patients with fibromyalgia compared to no exposure. The mechanism is unknown.

4.  Skin barrier functions. Skin exposed to UVB and UVA is more resistant to primary irritants. Once again, the mechanism is unknown.

5.  Protects from disease beyond vitamin D? In an animal model, researchers discovered that sun exposure is more protective and suppressive against multiple sclerosis than just vitamin D alone.

6.  Induces nitric oxide. UVA exposure induces nitric oxide (NO*) production. It has been suggested that NO* protects the skin for 20-30 minutes from UV damage, offers cardiovascular protection, helps wounds and have some anti-tumor activity.

One area that the authors did not mention was melatonin regulation. It is believed that the more light one is exposed to during the day, the sooner melatonin production occurs at night. Melatonin is involved in the sleep-wake schedule and when released, makes the body drowsier and cooler.

While there is much work to be done in the realm of figuring out specific mechanisms of action induced by UV exposure, we have some clues as to what sun exposure accomplishes outside of vitamin D production.

16 Responses to Sun exposure: Benefits beyond D production

  1. John

    When sunlight enters the eyes it stimulates the pineal gland

  2. silvalli

    Refernces, please?

  3. Jim Larsen

    And SAD. Seems to respond to different wavelengths than UVB.

  4. Brant Cebulla

    silvalli, not sure if you’re speaking to John or myself, but the linked reference in the blog is the reference for all information in this blog.

  5. Ron Carmichael

    I like to tell people that if Doc Holliday, who went west to dry his lungs out from consumption’s edema, had worn a speedo he probably would have lasted a lot longer (athletic enhancement as well as immune system benefits). It seems to carry the point in a positive way – imagine a cowboy running around the OK corral in a bright red speedo and boots. Eeyewwwwww!

    • Brant Cebulla

      Nice reference, Ron. Tombstone has got to be one of my favorite movies. Would be curious to measure levels during the “Wild West.” Maybe a similar study would be a summer draw of ranchers’ levels and see if exposure to hands, face and neck do much of anything.


  6. Dan

    Can UV-A and UV-B through the eye be beneficial? I ask because as a contacts and eyeglass wearer I know these aids block most of the UV rays.

  7. Rebecca Oshiro

    Chapter 6 of Michael Holick’s “The Vitamin D Solution” goes into detail regarding the mechanisms behind the stimulation of the pineal gland by sunlight. He also talks about the exciting research behind light therapy for SAD and PMS and his clinical experience in this area.

  8. [email protected]

    Brant, regarding day light priming night/sleep time melatonin release, does a particular wavelength band do most of the priming?

    • Brant Cebulla

      Yes, blue light, which actually plays a role in the melatonin cycle via the retina.

      So technically speaking, the sun’s effect in regards to melatonin probably does not have anything to do with the skin, rather the retina, and that is why the authors did not mention it. There is probably someone here who knows a bit more about this. Anyone?

  9. [email protected]

    Not to mention that getting sunshine will boost a mans testosterone.
    Will just taking Vit D do that? I don’t know. But, according to this article sunshine can increase it by up to 69%.

  10. Rebecca Oshiro

    Brant, it is my understanding that it is the brightness of the light (measured in Lux) that has the effect and not the wavelength.

  11. Brant Cebulla

    Thanks Rebecca. Do you have a good article to point us all to?

  12. Rebecca Oshiro

    Chapter 6 of Michael Holick’s “The Vitamin D Solution” goes into detail on most of things in this thread!

  13. PeterVermont

    @Ron Carmichael — I just read the excellent “Doc: A Novel” by Mary Doria Russell and I had the same thought about Doc Holliday’s tuberculosis. Unfortunately he was a big card player which meant he basically worked nights and slept days. It did mention a brief period where he went riding every day during the day where he improved quite a bit.

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