SCIENTISTS are launching a study in a bid to combat the health risks Scots face due to a lack of sun exposure during winter.
Aberdeen University is behind the research which will test two methods to counter the negative effects of living so far away from the equator.
Due to the angle of the sun in the winter months, Scots do not receive the UVB rays their bodies need to make vitamin D, which is essential for healthy bones.
Some studies have also suggested links between vitamin D deficiency and immune system diseases such as multiple sclerosis.
The north of Scotland has a high prevalence of MS and a recent study found the Orkney Islands have the highest rate of the disease in the world.
Other countries at northerly latitude such as Canada also have a high MS prevalence.
University researchers are looking for healthy volunteers to help them examine the effects of vitamin D supplements and also artificial UVB light - mimicking sunlight - on the body's immune system.
The study follows on from findings revealed by the team two years ago, which showed a link between sunlight, vitamin D and cells in the body, known as regulatory T cells which play a vital role in the immune system, preventing damaging responses.
The new study aims to recruit 50 healthy volunteers over the age of 16 who are not taking vitamin D, are not allergic to the sun and are able to travel to Aberdeen's Foresterhill campus.
They will be given either vitamin D supplements or have a series of UVB therapy treatments currently used to treat dermatology patients at Aberdeen Royal Infirmary.
Professor Anthony Ormerod, Professor of Dermatology at Aberdeen University, said: "The problem with being so far north of the equator is the lack of sunlight and there is a seasonal incidence with certain diseases which increases the further you are from the equator.
"Sunlight is our main source of vitamin D but the further you are from the equator the less sun exposure you get.
"This is a particular problem during winter because the useful UVB rays are filtered out and don't reach us.
"Unless we take a winter sunshine holiday or vitamin D supplements, we are reliant on the store of vitamin D that has been built up by the body during the rest of the year."
Professor Helen Macdonald, Professor of Nutrition and Musculoskeletal Health at the university, said: "We want to see whether giving volunteers vitamin D or artificial UVB light can counter the problem of lack of sunlight and improve our health.
"Vitamin D is important for bones and vitamin D deficiency has also been linked with cancer, cardiovascular disease and autoimmune diseases such as MS.
"We will be looking to see whether artificial sunlight or vitamin tablets will keep our immune systems in check.
"Blood samples will also be taken to enable us to see what is happening in the body."
Professor Ormerod said that it was hoped the study would point out a way to improve the health of the community.