Vitamin-D is not a vitamin in the traditional sense, but rather a steroid hormone which your body makes under the right circumstances. Its important for the body in a number of ways including maintaining a functional immune system.
One of the wide spread concerns most commonly associated with vitamin-d is the inability to get the daily recommended intake. It is made in the skin from cholesterol then the liver converts the change into a more potent form. In order for the skin to make this process possible the skin needs enough ultraviolet rays.
Studies have confirmed people with seborrheic dermatitis who do not get the adequate levels of vitamin-d see their symptoms worsen. Comparatively, those who supplemented with vitamin-d with food/vitamins/sun saw drastic improvements.
For instance, whenever I am travelling on a vacation to a warm tropical climate with a lot of sun I notice an immediate improvement. My scalp, neck and face is minimized of flaking while the redness lightens so its not as pronounced. Conversely, if I am in a colder climate during the winter and there’s very little sun during daytime then the inevitable worsening of symptoms is all but assured.
I believe the sun’s ultraviolet rays play another crucial factor with those suffering from seborrheic dermatitis by inhibiting the growth of the Malassezia Furfur. This common fungus found on the human skin only causes problems with people with seborrheic dermatitis.
If you’re lucky enough to live in a place with plenty of sun you probably get enough vitamin-d from being outside. Unfortunately for those who live elsewhere in under less than ideal conditions, then you will need to get your vitamin-d from other sources.
A good source of vitamin-d is cod liver oil. This fish oil can be found in small capsules that you can simply swallow on a daily basis. Another source is just by taking vitamins with vitamin-d. The daily vitamind-d recommendation is around 600-2000iu.