Exposure to the sun is responsible for over 90% of vitamin D production but can be dangerous, particularly in cases of vitiligo. Thus, individuals affected by this skin condition often fear a deficiency in vitamin D. Is this risk real? Let's explore this question together.
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Can vitiligo cause a vitamin D deficiency?
Summary
Published November 21, 2024,
updated on November 21, 2024,
by
Pauline, Chemical Engineer
—
7 min read
Vitamin D Deficiency: Are Individuals with Vitiligo at a Higher Risk?
Vitiligo is a skin condition closely related to skin pigmentation, characterized 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 color to the skin 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 with vitiligo, who have depigmented areas, must be particularly vigilant when exposed to the sun.
Nevertheless, in addition to having beneficial effects on mood, 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 isomerization before reaching the liver and being hydrolyzed 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 legitimate to question whether individuals affected by vitiligo, who avoid the sun, have a sufficient capacity to synthesize vitamin D. It should be noted that a vitamin D deficiency is defined as a serum level 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 studies are presented below.
| Study | Participants | Individuals affected by 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 & et al. (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. Additionally, to avoid Vitamin D deficiencies, one can supplement their diet with 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 a immunomodulatory effect. It helps to calm the immune system when it becomes overactive, an important property in autoimmune diseases such as the vitiligo, where the body mistakenly attacks its own melanocytes. A vitamin D deficiency could thus support this phenomenon.
That's 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.
Sources
ROBINSON J. Sun Exposure, Sun Protection, and Vitamin D. Journal of the American Medical Association (2005).
HAMZA H. & al. Evaluation of serum 25-hydroxyvitamin D levels in vitiligo patients with and without autoimmune diseases. Photodermatology, photoimmunology & photomedicine (2013).
ALGHAMDI K. & al. The Relationship Between the Serum Level of Vitamin D and Vitiligo: A Controlled Study on 300 Subjects. Journal of Cutaneous Medicine and Surgery (2015).
EKIZ O. & al. The role of serum vitamin D levels in vitiligo. Advances in Dermatology and Allergology (2016).
BORRADORI L. & al. Dermatologie et infections sexuellement transmissibles. Elsevier Masson (2017).
EZZEDINE K. & al. Vitiligo: A Review. Dermatology (2020).
KOSHI S. & al. Vitiligo: A Narrative Review. Cureus (2022).
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