High doses of oral vitamin D3 (cholecalciferol) taken one hour after sunburn might reduce skin redness, swelling, and inflammation, but further investigation is required, according to researchers who published their findings online in the Journal of Investigative Dermatology(May 30, 2017).
During this double-blinded, placebo-controlled interventional trial, 20 healthy adults were randomized to receive a placebo or a high dose of vitamin D3 (200,000 IU) one hour after experimental sunburn induced by an erythemogenic dose of ultraviolet radiation on their inner arm.
The researchers followed up with the subjects at 24, 48, 72 hours and one week after the experiment, and collected skin biopsies for further testing.
The findings revealed that compared to placebo, participants receiving vitamin D3 demonstrated reduced expression of pro-inflammatory mediators Tumor Necrosis Factor-α (TNF-α) (p=0.04) and inducible nitric oxide synthase (iNOS) (p=0.02) in skin biopsy specimens 48 hours after the sunburn was induced.
Data based on investigating global gene expression profiles revealed that participants with significantly higher serum vitamin D3 levels after treatment (p=0.007) demonstrated increased skin expression of the anti-inflammatory mediator arginase-1 (p=0.005), and a sustained reduction in skin redness (p=0.02), correlating with significant expression of genes related to skin barrier repair. In contrast, participants with lower serum vitamin D3 levels had significant expression of pro-inflammatory genes, the researchers wrote.
Benefits of vitamin D supplement were dose-dependent
“We found benefits from vitamin D were dose-dependent,” said Dr. Kurt Lu, senior author on the study. “We hypothesize that vitamin D helps 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.”
Dr. Lu, who was quoted in a press release, is an assistant professor of Dermatology at Case Western Reserve University School of Medicine and University Hospitals Cleveland Medical Center in Cleveland.
The trial describes the acute anti-inflammatory benefits from taking vitamin D. According to the authors, despite the widespread attention given to vitamin D deficiency, “there is a lack of evidence demonstrating that intervention with vitamin D is capable of resolving acute inflammation.”
Dr. Lui cautions against patients taking oral vitamin D3 to treat their sunburn. He stresses that the trial tested very high doses of vitamin D that far exceed daily allowances. The Food and Drug Administration’s recommended adult daily allowance for vitamin D is 400 IU.
“I would not recommend at this moment that people start taking [oral] vitamin D after sunburn based on this study alone. But, the results are promising and worthy of further study,” Dr. Lu concluded.