
Vitamin D is produced by skin cells in response to UV radiation emitted by the sun
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People with genetically higher vitamin D levels may be less likely to develop psoriasis, an autoimmune disease that causes inflamed, itchy patches on the skin. Previously, similar associations were found only between these gene mutations and another autoimmune disease, multiple sclerosis (MS).
In many countries, vitamin D is produced in the skin, so taking vitamin D supplements is recommended, especially for people who get little sun exposure.