Vitamin D: Starring Role in Restless Legs Syndrome?

Patients with restless legs syndrome saw significant improvement in symptoms after vitamin D supplementation.

Restless legs syndrome (RLS) creates abnormal sensations—usually in the legs, but sometime in the arms, body, or head—which lead to a relentless urge to relieve the feeling (restlessness). Affecting approximately 10% of Americans by middle age, this neurological disorder manifests in vastly different ways ranging from mild tickling, itching, or crawling feelings to outright aching and pain. Patients are most likely to notice the sensations when their movement slows (eg, when relaxing, reading, concentrating, or trying to sleep). To interrupt the feeling, patients are compelled to move and find temporary relief. Most RLS sufferers also experience periodic limb movement disorders like jerking legs or arms during sleep. Over time, these patients accumulate a sleep deficit and RLS erodes the quality of their life.

RLS is most often a primary idiopathic disorder, but research has shown that it also occurs secondary to iron deficiency, end-stage renal disease, diabetes mellitus, and other diseases. Prescription drugs of choice for the bothersome cases include levodopa or the dopamine agonist pramipexole.

Some case reports indicate that correction of vitamin D deficits may improve RLS symptoms. A study published in the August 2014 issue of Sleep and Breathing concludes that for some RLS sufferers, a trial of vitamin D supplementation may be warranted.

The researchers enrolled 12 adults with RLS from Saudi Arabia who also had vitamin D deficiencies. One-third of Saudi Arabia’s residents have vitamin D deficiency due to sun avoidance and their style of dress. Study participants with vitamin D levels lower than 50 nmol/L received vitamin D supplements orally or by intramuscular injection.

Before treatment with vitamin D, participants’ median level was 21.7 nmol/L. After treatment, the median rose to 61.8 nmol/L. Patients took vitamin D for between 3 and 8 months.

Participants’ median RLS severity score improved significantly from 26 at baseline as measured using a subjective assessment and patient recall scoring system to 10 after vitamin D levels were corrected.

Current research indicates that vitamin D may be a neuron-activating steroid critical to dopamine system functioning and seems to influence neurodegenerative disorders including multiple sclerosis and Parkinsonism. Only a few studies have looked at vitamin D’s potential relationship to RLS. This study, due its small size and subjective scoring system, results cannot be extrapolated. Its positive results suggest that larger studies are needed to determine if this simple intervention could help many RLS patients.