LONDON (BBC): The amount of time asthma patients spend soaking up the sun may have an impact on the illness, researchers have suggested. A team at King’s College London said low levels of vitamin D, which is made by the body in sunlight, was linked to a worsening of symptoms. Its latest research shows the vitamin calms an over-active part of the immune system in asthma. However, treating patients with vitamin D has not yet been tested.