Summer is just beginning, and with summer comes the beach, pool parties, or a variety of other outside activities. This means spending time in the sun and trying our best to protect our skin from the harmful UV radiation that it emits. Wearing sunscreen is important but lets face it, we are all human, sometimes we forget to apply, sometimes we don't apply often enough. This leads to sunburns.

Today lets take a look at an article published in the Journal of Investigative Dermatology titled "Oral vitamin D rapidly attenuates inflammation from sunburn: an interventional study." This article is available for use under a creative commons attribution license, as such all material from the article will be appropriately credited.

Source For Sunburn Image

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Sunburns

A sunburn is a radiation burn (in this case the radiation is ultra violet light), when the ultraviolet light hits your skin it penetrates into the cells and actually induces changes to their DNA. It results in a variety of deleterious DNA lesions including thymine-dimers (when two stacked T's (thymines) actually form a chemical bond to one another). These forms of damage wreak havoc on cellular DNA replication processes and will stop DNA polymerases (the replicative ones, not certain specialized repair enzymes) in their tracks.

If you have a little bit of damage, the cells have the necessary enzymes to conduct a repair mission, restore DNA replication to normal functioning and continue on their merry way. However if there is just a whole crap ton (to use a very scientific term) of damage (from longer sun exposure) they can't fix everything. When cells can't fix the errors, which spells trouble and can lead to a whole host of potential issues (including cancer). Our cells are programmed to kill themselves in this situation, thus they begin the process of doing so, called apoptosis. The cells killing themselves results in an inflammatory response, and this inflammatory response is what we all know of as a sunburn.

Be careful there pupper, you can get sunburned too

Vitamin D

Vitamin D actually does not refer to just one compound, rather a few (D₃([Cholecalciferol)(https://en.wikipedia.org/wiki/Cholecalciferol), D₂(Ergocalciferol and the less important D₂ which is actually a mixture of D₂ and the compound Lumisterol). The D vitamins are fat soluble compounds with a whole host of important biological functions including calcium shuttling, bone development and influence on inflammation levels [2]. Vitamin D is only a vitamin by technicality as our bodies are able to synthesize all that we need from 10 minutes daily exposure to the sun [3].

Making that sweet sweet vitamin D

What Were The Researchers Studying

Due to the recent finding that a single dose of vitamin D₃ was capable of rapidly decreasing inflammation in a mouse model for chemical skin injury [4] the authors hypothesized that it could be used to reduce the inflammation of a sunburn. So they designed a proof of principle double blind clinical trial to test this hypothesis [yes @lemouth, the sample size here is also small, only 20 people ;)].

In their study the participants received either a placebo or a high dose of vitamin D₃ one hour after they were blasted with enough ultra violet radiation to cause a “sunburn” though in this case the sun was not used… so it was more of a lab burn? This sounds like a great study, I wonder what the participants were asked… “Come participate, will give you sunburn for $$$.” Regardless, the results might interest you.

What Did They Find?

They blasted the participants skin with UVB radiation, then waited 48 hours and took a look at the skin redness. In the figure below you are seeing 4 spots on a participants arm where they were blasted with increasing amounts of UV radiation (from left to right).

Figure 2a

What you can make note of from the figure above, is the last group on the right, for the very high dose of vitamin D₃. The top set is a control where the participant did not receive the vitamin D, and the bottom is where that same participant did. You will notice that there is significantly less redness (especially at lower amounts of UV) in the bottom set. This indicates that a high dose of vitamin D did have an effect in reducing the inflammation from the sunburn. (For this result the authors report a P value of 0.02, where they were concluding statistical significance for any P < 0.05)

In addition to visual queues, the authors also took a look at the amounts of proteins that are expressed in inflammatory processes. These were 'Tumor Necrosis Factor-α (TNF-α) and cytokine inducible Nitric Oxide Synthetase (iNOS).

Figure 2c

Here they were looking at the expression levels of these proteins based upon how much mRNA was being generated (remember mRNA is the instruction sheet telling the cell to make a protein, more mRNA = more protein generated, because there are more instructions floating around). What we can see here is that both of these proteins involved in the inflammatory response are reduced in expression levels as the amount of vitamin D supplemented goes up.

Other Important Observations

• The overall cellular gene expression profile for those receiving the high (200,000 IU) dose of vitamin D₃ was very different from the placebo group.
• NOT all participants receiving higher doses of Vitamin D₃ showed a response. As a result the authors classified the participants into two groups (Responders and Non-responders)
• Non responders had very different gene expression profiles then people who did respond better to the vitamin. They expressed a lot more proteins which are pro-inflammatory (IE lead to and participate in the inflammatory response).

Brief Conclusions

• The authors here have illustrated evidence that a single high dose of vitamin D₃ administered one hour after sun exposure helped to alleviate the inflammatory response associated with sunburn.
• The administration of the single high dose of the vitamin did not negatively alter the participants calcium levels.

The simplicity and safety of high dose oral vitamin D3 treatment, combined with its rapid and sustained therapeutic efficacy, suggest that these proof-of-concept findings may ultimately be translated to routine clinical use once larger studies are performed on diverse populations of subjects.

The results reported here are interesting and do hold promise for future research.

Should I Self Medicate With Vitamin D After Sun Exposure?

NO, this data is not sufficient to justify self medication.

It is just some interesting science that I hope you enjoyed learning about.

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# Sources

1. http://www.sciencedirect.com/science/article/pii/S0022202X17315580
2. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
3. http://health.usnews.com/health-news/family-health/heart/articles/2008/06/23/time-in-the-sun-how-much-is-needed-for-vitamin-d
4. https://www.ncbi.nlm.nih.gov/pubmed/26288355

All Non Cited Images Are From Pixabay.com or Flickr.com And Are Available Under Creative Commons Licenses

Any Gifs Are From Giphy.com and Are Also Available for Use Under Creative Commons Licences

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