Restless legs syndrome (RLS) is marked by a pervasive twitching, tingling or burning sensation in the legs, particularly at night or during other periods of rest. These sensations cause sleep disruptions, leading to poor mental focus and daytime fatigue. Preliminary research suggests that a vitamin B12 deficiency may be connected to restless legs.
Vitamin B12
B12 is a water-soluble vitamin found in certain foods and available as a dietary supplement. It contains cobalt, a naturally occurring mineral. This vitamin binds to proteins and releases during gastric protease and hydrochloric acid activity in the stomach. Two types of B12 compounds, methylcobalamin and 5-deoxyadenosylcobalamin, interact with the human metabolism.
Sources of B12
Vitamin B12 can be found naturally in animal foods. The foods with the highest natural amounts of B12 are beef liver, clams, trout, salmon and sirloin beef. Dairy products such as yogurt, cheese and milk are also good sources of B12. This vitamin is not found naturally in grains and plant foods, but breakfast cereals typically are fortified with B12. People who exhibit B12 deficiencies also may obtain this vitamin through supplements, prescription medications or injections.
B12 Deficiency
A deficiency of vitamin B12 is known to cause neurological changes in the body, as well as general fatigue and weakness. These neurological changes can show up as tingling or numbing sensations in the limbs and extremities. Because restless legs syndrome is a neurological disorder, a B12 deficiency has been identified as one of the potential causes.
B12 and Folic Acid
Folic acid has been used successfully to treat restless legs syndrome--patients who take between 5 and 10 mg per day have reported a decrease in symptoms related to RLS. Although folic acid is useful for treating RLS, high levels can mask the symptoms of vitamin B12 deficiency. It also can worsen B12 deficiency symptoms such as anemia and cognitive impairment. Patients with restless legs should have their B12 levels checked before beginning a folic acid regimen.
Contraindications
Patients with Leber's optic atrophy or coronary stents should not take B12 supplements. Vitamin B12 also should not be taken by patients who are allergic to cobalt or cobalamin. Otherwise, vitamin B12 exhibits a low potential for toxicity, even when taken in large doses.
