ARTIFICIAL sunlight therapy may help alleviate autoimmune diseases such as multiple sclerosis (MS) and type 1 diabetes, Scots researchers have found.

Scientists at Aberdeen University studied patients in the north of Scotland – which has the highest rate of MS in the UK – who were being treated during winter with artificial UV-B light therapy for skin diseases caused by their immune systems acting inappropriately.

They found the UV-B rays were boosting levels of vitamin D in the patients' bodies as well as enhancing the function of regulatory T cells, which are responsible for controlling and balancing the immune system.

Autoimmune diseases are conditions where the immune system mistakenly attacks the body's own tissues or harmless substances that enter the body.

Previous research suggested a link between vitamin D deficiency and autoimmune diseases in regions far north of the equator, but this is the first time scientists have pin-pointed a clear interplay between vitamin D, UV-B light and T cells.

Vitamin D is manufactured naturally in the body in response to sunlight, but relatively low levels of exposure to sunshine in countries such as Scotland – especially during winter – has been blamed for the nation's poor health record for a number of ailments.

Dr Anthony Ormerod, clinical reader in dermatology at the university, said: "Our study shows UV-B light, which mimics sunshine, can have a striking effect on the immune system of patients. We found UV-B light boosted the production of vitamin D, and of regulatory T cells, which play an important role keeping our immune systems in check.

"Our findings have important implications for future interventions including the recommendations for healthy lifestyle and a possible role for phototherapy and/or vitamin D supplementation in the prevention or treatment of autoimmune and inflammatory diseases.

"While too much exposure to sunlight is harmful, these results suggest subjects in our study would have some benefits from small amounts equivalent to summer exposure in the winter but more work is needed to determine the role of sunlight and the role of supplementing the diet with vitamin D."

Dr Helen Macdonald, senior lecturer in nutrition and translational musculoskeletal research at the university and chair of the National Osteoporosis Society's nutrition and lifestyle forum, added: "We are not advocating sunbed use since this is not the same type of radiation produced by sunbeds which already have health risks.

"The average dose of UV light the volunteers received was the equivalent to sunlight exposure in Aberdeen over spring and summer and further work is required to determine if lower doses are effective."

The research is published in the Journal of Allergy and Clinical Immunology.