Our skin needs sunlight in order to synthesise Vitamin D. Due to our modern indoor lifestyles, as well as the overuse of sunscreens, we have reduced our sunlight exposure significantly, which has resulted in Vitamin D deficiency among many populations, even in sunny countries.
Vitamin D performs many functions in the skin, including the modulation of immune responses, differentiation and proliferation of keratinocytes, reduction of inflammation and much more. Keratinocyte differentiation and inflammation are both factors in driving acne.
To make Vitamin D, your body needs the starting material. This is where 7-dehydrocholesterol (7-DHC) comes in. 7-DHC absorbs Ultraviolet B Radiation from the sun, which results in a reaction that makes Previtamin D. This happens quickly, especially when light of the perfect wavelength is used. This means that even a very short exposure time will allow for the production of significant amounts of Previtamin D. From there, Previtamin D is slowly isomerised to Vitamin D in the membranes of skin cells. It’s a good thing that the conversion from Previtamin D to Vitamin D is slow, as it means a short exposure time can still lead to sustained release of Vitamin D over the next while.
Some activities of Vitamin D that are particularly beneficial to acne-prone skin:
- Inflammation plays an important role in the pathogenesis of acne, and Vitamin D acts to reduce the expression of inflammatory cytokines, avoiding a maintained state of inflammation in the skin.
- Another mechanism of acne pathogenesis is an abnormal proliferation of keratinocytes. Vitamin D inhibits keratinocyte proliferation and regulates differentiation and apoptosis. This helps to re-establish a healthy balance.
- Vitamin D receptor (VDR) and its coactivators regulate barrier function and the production of sphingolipids. The receptor and its coactivators also play an essential role in the differentiation of keratinocytes.
- It has been found that human sebocytes (the cells managing sebum production) express Vitamin D receptors on their membranes. This indicates that Vitamin D regulates the proliferation of sebocytes, as well as some aspects of sebum production.
- Vitamin D stimulates the production of antimicrobial peptides by your skin cells.
Providing your skin with the ability to regulate its immune responses more effectively means that it can structure an environment that encourages the growth of beneficial microbes, as well as being better able to fight off pathogenic microbes.