Abstract
Multiple sclerosis is a demyelinating autoimmune disease that commonly affects young people. Several risk factors are associated with multiple sclerosis, including low vitamin D levels. Vitamin D is essential in various regulatory processes, particularly in the immune system. Fifty years ago, vitamin D was suggested to have a role in the risk of multiple sclerosis development and relapses, which was proposed after reporting seasonal and geographic variation of multiple sclerosis incidence around the world. This literature review is intended to review the potential role of vitamin D in the risk of multiple sclerosis development or relapses. 21 articles have been selected according to the following Mesh words: Multiple sclerosis, multiple sclerosis relapse, vitamin D, cholecalciferol. Vitamin D seems to play an essential role in the immunological processes involved in multiple sclerosis, along with the indirect beneficial impact of sunlight exposure. However, up to our knowledge, there is no established consensus about the exact vitamin D's beneficial role of among MS patients. Further multi-center randomized clinical trials are recommended to establish the preventable or therapeutic role of vitamin D in MS.