Vitamin D3 Status & Skin Health

In early studies Vitamin D was acknowledged for its role in bone formation, with later research providing evidence of its involvement in proper function of multiple bodily tissues including muscles, brain, heart, immune system, and skin (Mostafa, 2015). Its deficiency is therefore implicated in numerous chronic health conditions including neurological, autoimmune, and cardiovascular disorders.

Interestingly, it was through historical accident that Vitamin D became classified as a ‘vitamin’, a term that implies the body is unable to metabolically synthesize the compound in question (Norman, 2012).  The contradiction being that Vitamin D is actually a fat-soluble prohormone steroid, and diet that is not fortified/supplemented is usually low in this vitamin.

When skin is exposed to sunlight, the sun’s UVB rays interact with a protein called 7-DHC in the skin, converting it into vitamin D3, the active form of vitamin D. Vitamin D3 starts off as cholecalciferol which then goes through numerous processes in the liver and kidneys to become the bioavailable form (a form that our body can easily use), calcitriol. Calcitriol can then be picked up by Vitamin D Receptors in the body and this binding of the two triggers important bodily processes that aid calcium metabolism, immune function, heart health, and many more (Charoenngam, 2020).

Vitamin D has anti-inflammatory properties which are helpful in skin conditions such as eczema and psoriasis. Active Vitamin D has the ability to modulate adaptive immune response by inhibiting pro-inflammatory T cell proliferation (Kim, G. 2016). It is also vital for the growth and repair of skin cells which supports the skin’s barrier, leaving it less vulnerable to structural attacks. One of the ways Vitamin D does this is through increased filaggrin expression, a protein that helps strengthen our skin barrier (O’Regan, 2008). If this barrier is compromised, it leaves us at increased risk of infection or a contact allergen triggering a flare. Research has identified Vitamin D deficiency as a risk factor for both psoriasis and eczema and shown maintaining optimum Vitamin D levels can lead to a reduction in the severity of symptoms, particularly inflammation and irritation (Kim, MJ. 2016).

Good sources of Vitamin D3:

• Sunlight: spending 20 minutes outdoors per day with skin exposed is the most convenient way of getting natural Vitamin D3. Early morning light contains less harmful UV rays and also helps regulate our circadian rhythm.

• Diet: oily fish (salmon, mackerel, herring, sardines), egg yolks, mushrooms, and fortified foods are good sources.

• Supplements: The recommended daily intake varies depending on age, sun exposure, weight, race, and health status. The HSE recommends 15 µg (600 IU) age 13-64 between October-March as a general guideline. Optimal supplementation is individual, speak to your health or nutrition practitioner to see which dose is right for you.

Multiple factors can influence your ability to utilize and retain Vitamin D including gene variants. Nutrigenomic testing can be used to see the relationship between specific genes and how they may be impacting on an individual’s skin health. It is important to note that too much Vitamin D, particularly in supplemented form, can have adverse effects on health. Always speak to a health or nutrition practitioner and test to check where your base levels are before starting to supplement.

References

Charoenngam N, Holick MF. (2020) Immunologic effects of vitamin d on human health and disease. Nutrients.12(7):1–28.   

Kim, G., & Bae, J. H. (2016). Vitamin D and atopic dermatitis: A systematic review and meta-analysis. Nutrition (Burbank, Los Angeles County, Calif.), 32(9), 913–920.

Kim MJ, Kim SN, Lee YW, Choe YB, Ahn KJ. (2016) Vitamin D status and efficacy of vitamin D supplementation in atopic dermatitis: A systematic review and meta-analysis. Nutrients. 8(12):8–17.

Mostafa WZ, Hegazy RA. (2015) Vitamin D and the skin: Focus on a complex relationship: A review. J Adv Res. Nov;6(6):793-804.

Norman A. W. (2012). The history of the discovery of vitamin D and its daughter steroid hormone. Annals of nutrition & metabolism, 61(3), 199–206.

O’Regan GM, Sandilands A, McLean WHI, Irvine AD. (2008) Filaggrin in atopic dermatitis. J Allergy Clin Immunol. ;122(4):689–93.