Writing in the Journal of Investigative Dermatology, findings from the placebo-controlled trial suggest that vitamin D supplementation had a dose-dependent effect on sunburn when taken one-hour after exposure.
The pilot-scale ‘proof-of-principle’ study provides initial in vivo evidence that a single high-dise of oral vitamin D3 can impact local inflammatory responses to ultraviolet radiation (IVR), said the authors – led by first author Dr Jeffrey Scott from University Hospitals Cleveland Medical Center.
While the current study looked at data from just 20 people, those behind the research think the findings could have big public health promise – if replicated in bigger trials.
“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,” said the team.
Senior author, Dr Kurt Lu at Case Western Reserve University School of Medicine noted that the team’s initial hypothesis had been that vitamin D helps to promote protective barriers in the skin by rapidly reducing inflammation.
“What we did not expect was that at a certain dose, vitamin D not only was capable of suppressing inflammation, it was also activating skin repair genes,” he said.
However, Lu also noted that the trial tested very high doses of vitamin D that far exceed daily recommended allowances.
"I would not recommend at this moment that people start taking vitamin D after sunburn based on this study alone,” Lu commented. “But, the results are promising and worthy of further study."
The team are now planning further studies that could also show benefits for people suffering from burns.
In the study, 20 participants were randomised to receive a placebo pill or 50,000, 100,000, or 200,000 international units (IU) of vitamin D one hour after a small UV lamp ‘sunburn’ on their inner arm.
The team followed up with the participants 24, 48, 72 hours and 1 week after the experiment and collected skin biopsies for further testing.
They found that those who consumed the highest doses of vitamin D had long-lasting benefits – including less skin inflammation 48 hours after the burn.
In addition to sustained reduction in skin redness following experimental sunburn, and less epidermal structural damage, the researchers reported reduced expression of pro-inflammatory markers in the skin, and a gene expression profile characterised by up regulation of skin barrier repair genes.
Compared to placebo, participants receiving vitamin D3 (200,000 IU) demonstrated reduced expression of pro-inflammatory mediators TNF-α and iNOS in skin biopsy specimens 48 hours after experimental sunburn.
“Together the data may have broad implications for the immunotherapeutic properties of vitamin D in skin homeostasis, and implicate arginase-1 up regulation as a previously unreported mechanism by which vitamin D exerts anti-inflammatory effects in humans,” said the authors.
Source: The Journal of Investigative Dermatology
Published online ahead of print, doi: 10.1016/j.jid.2017.04.040
“Oral vitamin D rapidly attenuates inflammation from sunburn: an interventional study”
Authors: Jeffrey F. Scott, et al