Does vitiligo promote a deficiency in Vitamin D?

Can vitiligo cause a deficiency in Vitamin D?

Exposure to the sun is responsible for over 90% of vitamin D production but can be dangerous, particularly in cases of vitiligo. Therefore, individuals affected by this skin condition often fear they may have a vitamin D deficiency. Is this risk real? Let's explore this question together.

Published on November 21, 2024, updated on November 21, 2024, by Pauline, Chemical Engineer — 7 min of reading

Vitamin D Deficiency: Are individuals affected by vitiligo at a higher risk?

Vitiligo is a skin condition closely related to skin pigmentation, characterised by the appearance of white patches on the skin. This phenomenon results from the selective loss of melanocytes, the cells responsible for the production of melanin, the pigment that gives skin its colour and plays a crucial role in protecting it from the sun's ultraviolet rays. In the absence of melanin, exposed areas are particularly susceptible to sunburn, melanomas, carcinomas and other UV-induced cellular damage. This is why fair skin is very vulnerable to the sun, although it is also important for darker skin to protect itself with a sunscreen.

Individuals suffering from vitiligo, who have depigmented areas, must be particularly vigilant when exposed to the sun.

Nevertheless, in addition to having beneficial effects on morale, exposure to the sun allows the body to synthesize vitamin D. From a mechanistic perspective, UVB rays convert 7-dehydrocholesterol in the epidermis into pre-vitamin D3. This then forms vitamin D3 through progressive thermal isomerisation before reaching the liver and being hydrolysed into 25-hydroxyvitamin D [25(OH)D], the circulating form. Subsequently, it is transported to the kidneys to undergo a second hydroxylation and become calcitriol 1,25(OH)2D, which is the active form of vitamin D. This plays a fundamental role in the body. It is particularly essential for bone health and contributes to the proper functioning of the immune system.

In this context, it is valid to question whether individuals affected by vitiligo, who avoid the sun, have a sufficient capacity to synthesise vitamin D. It's worth noting that we refer to a deficiency in vitamin D when the serum level is below 10 ng/mL, even though the recommended level is above 30 ng/mL. Several studies have investigated the risk of vitamin D deficiency in individuals with vitiligo, but have reached different conclusions. The results of three of these are outlined below.

Study	Participants	Individuals suffering from vitiligo	"Healthy" Individuals	Conclusion
HAMZA & et al. (2013)	40 individuals with vitiligo and 40 "healthy" individuals	39 (97.5%) had a deficiency in Vitamin D	5 (12.5%) had a deficiency in Vitamin D	Significant difference between the groups
ALGHAMDI & co. (2015)	150 individuals with vitiligo and 150 "healthy" individuals	137 (91.3%) had a deficiency in Vitamin D	136 (90.7%) had a deficiency in Vitamin D	No significant difference between the groups
EKIZ & al. (2016)	50 individuals with vitiligo and 47 "healthy" individuals	Average serum level of Vitamin D: 12.04 ± 8.84 ng/mL	Average serum level of Vitamin D: 12.91 ± 6.08 ng/mL	No significant difference between the groups

Étude du lien entre vitiligo et carence en vitamine D.

It is challenging to assert that individuals with vitiligo have a higher risk of Vitamin D deficiency, but this hypothesis cannot be ruled out.

To prevent the risk of Vitamin D deficiency, individuals affected by vitiligo must find a balance between sun exposure and protection. It is unnecessary and not recommended to completely avoid the sun: one simply needs to take precautionary measures, such as regularly applying a sufficient amount of sun protection and avoiding direct exposure between 11 am and 4 pm, the times of day when UV rays are most intense. Moreover, to avoid Vitamin D deficiencies, it is possible to supplement through dietary supplements. Milk is another source: a 250 mL glass of milk contains about 100 IU of Vitamin D, which is a tenth of the recommended daily intake. Fatty fish, like salmon or mackerel, are also rich in Vitamin D.

Conversely, can a deficiency in Vitamin D cause vitiligo?

The reverse question can also be asked: can a vitamin D deficiency increase the risks of vitiligo? While this question has not yet been definitively answered, it is possible that a vitamin D deficiency may promote vitiligo flare-ups because this compound has an immunomodulatory effect. It helps to calm the immune system when it becomes overactive, an important property in autoimmune diseases such as vitiligo, where the body mistakenly attacks its own melanocytes. A vitamin D deficiency could thus support this phenomenon.

This is why vitamin D analogues, particularly calcipotriol and tacalcitol, have been studied as topical therapeutic agents in vitiligo. They would target the local immune response and act on the specific activation of T cells. These vitamin D3 compounds would also influence the maturation and differentiation of melanocytes, in addition to regulating melanogenesis. However, further research is still needed on this subject. It is likely that vitamin D analogues are more of a complementary therapy than a monotherapy.