Vitamin D is made by skin cells in response to ultraviolet light emitted by the sun Milo Zanecchia/Ascent Xmedia/Getty Images
People who are genetically predisposed to have higher vitamin D levels may be less likely to develop psoriasis, an autoimmune condition where the skin develops inflamed and itchy patches. Until now, a similar link had only been seen between these gene variants and multiple sclerosis (MS), another autoimmune condition.
In many countries, people are advised to take vitamin D supplements, especially if they get little sun exposure, because the vitamin is made by skin …
