Multiple sclerosis and vitamin D

IS VITAMIN D AND WHY IS IT IMPORTANT IN MS?Vitamin D is a vitamin that acts like a hormone in the human body.We get vitamin D from sunlight, food, or dietary supplements.The study by Stein et al. 1 examines the relationship of vitamin D and MS.In addition, a recent Patient Page in Neurology ® focused on the actions of vitamin D and vitamin D deficiency. 2 The best level of vitamin D for health is uncertain and may vary depending on the part of the body vitamin D acts on.Many experts believe that blood levels of vitamin D above 30 ng/mL are adequate.(Some studies, such as the present study, use different units of measurement [nmol/L] than are common in the United States.A conversion factor of 2.496 is necessary to switch between these unit systems, and a vitamin D level of 30 ng/mL would be approximately 75 nmol/L in the present study. 1 ) Vitamin D appears to act on a number of different systems in the human body.In particular, vitamin D seems to be important for function of the immune system.Therefore, deficiency of vitamin D may play a role in diseases thought to be caused by improper immune responses (autoimmune diseases), including multiple sclerosis (MS).A recent Patient Page in Neurology provided a thoughtful summary of what is known about MS. 3 Previous studies have found that low vitamin D levels may increase the risk of developing MS. 4 -8 A number of studies have also suggested that patients with MS with low levels of vitamin D are at an increased risk of new MS attacks ("relapses"), new lesions on MRI, and disability compared to patients with higher vitamin D levels.4 -8 These studies mostly looked at a connection with previous and current vitamin D levels, rather than at the effect of supplementing vitamin D. Most found that patients with MS appeared to benefit from having adequate vitamin D levels (i.e., approximately 30 ng/mL) compared to insufficiency (20 -29 ng/mL) or deficiency (less than 20 ng/mL).A few studies also suggested that levels higher than 30 ng/mL may further help protect patients with MS. WHAT DID THE AUTHORS STUDY?In the present study, Stein et al. 1 examined whether high vita-