Comprising the “tanning rays” from the sun that are blocked by sunscreen and long feared for supposedly causing wrinkles and “age spots”, UV-B light, it turns out, actually promotes health by increasing levels of vitamin D. Now a team of scientists from St. Vincent’s University Hospital in Dublin, Ireland, have found that treatment with narrow-band UV-B rays greatly increases serum levels of vitamin D in the wintertime. And they’ve shown how adequate exposure to UV-B light therapy can clear psoriasis. In fact, the new finding is powerful evidence that a lack of the “sunshine” vitamin is involved in the development and worsening of this skin condition.
The researchers studied 30 consecutive patients with psoriasis who were treated with narrow-band UV-B light three times per week between October 2008 and February 2009. The research subjects’ psoriasis cleared and their serum vitamin D levels (which were measured before the study, after four weeks of treatment and after the treatment was finished) were compared with those of 30 control patients who also had psoriasis but did not have any UV-B therapy. The researchers also assessed the severity of the patients’ psoriasis symptoms and their skin disease-related quality of life before and after treatment.
The results showed that levels of serum 25-hydroxyvitamin D, which is considered the most accurate measurement of vitamin D levels in the body, had increased significantly among individuals receiving UV-B therapy — rising from about 23 nanograms per milliliter to 59 nanograms per milliliter at the end of treatment. However, there was no change in the control group.