Restless leg syndrome, or RLS, is a neurological condition that involves involuntary twitching of leg muscles, especially at night. According to the Restless Leg Syndrome Foundation, between 3 and 15 percent of the U.S. population -- mostly female -- experience leg symptoms that might be RLS. The causes of RLS are unknown, although genetics, drug interactions, nutritional deficiencies and other diseases are possibilities. Magnesium is important for normal muscle activity and low levels may play a role in RLS.
Primary Symptoms of RLS
According to the National Institute of Neurological Disorders and Stroke, people with RLS feel uncomfortable sensations in their legs, often described as crawling, creeping, twitching or tugging. These sensations are most prominent when sitting or lying down, especially at night, which may severely disrupt sleep. RLS usually affects both legs and is accompanied by an irresistible urge to move the legs, which often gives temporary relief. Going to bed, long car trips or sitting in a movie theater can trigger RLS. People with RLS often appear fidgety, because they keep their legs in motion to minimize or prevent the sensations. People with RLS may pace the floor, constantly cross and uncross their legs and toss and turn in bed.
Possible Causes of RLS
The primary cause of RLS is unknown, although the medical community believes there may be a genetic component as specific gene variants have been associated with the condition, according to "Human Biochemistry and Disease." Some evidence points toward low levels of iron in the brain as being responsible for RLS, as neurotransmitter imbalance is a consequence of iron deficiency. According to "Professional Guide to Diseases," RLS seems to be related to dysfunction in the basal ganglia of the brain, which uses dopamine to produce smooth, controlled muscle contractions. Disrupted production of dopamine can result in involuntary muscle movements, as seen in Parkinson's disease. In addition to drug interactions, dietary neurotoxins, kidney disease and pregnancy, mineral deficiencies have been proposed as potential causes of RLS. Some believe that magnesium deficiency is widespread within the U.S. and causes numerous conditions, including those related to abnormal muscle function.
Potential Role of Magnesium in RLS
Magnesium is an important mineral for healthy bones, but also for appropriate muscle contraction and relaxation. According to "Doctor's Complete Guide to Vitamins and Minerals," magnesium deficiency can cause muscle tension, muscle cramps and possibly sensations similar to what has been described for RLS. The increased muscle tension from magnesium deficiency can disrupt the early stages of non-REM sleep, which depends on reduced muscular tension to progress towards deep sleep stages. Insomnia and lack of deep sleep further affect muscle function, as twitches, cramps and reduced muscle strength are common among people who are chronically sleep deprived. Thus, some cases of RLS may be the advanced symptoms of sleep deprivation, which can be initiated by the effects of magnesium deficiency.
Magnesium Sources and Supplements
According to the National Institutes of Health, the recommended daily intake of magnesium is 420 mg for men and 320 mg for non-pregnant women. Rich food sources of magnesium include spinach, fish, especially if eaten with the bones, most legumes, such as lentils and black eyed peas, some nuts, such as almonds and cashews, yogurt, brown rice and bananas. Magnesium supplements can be taken and are often part of a multi-mineral. Magnesium oxide is considered the most bio-available form.
References
- Restless Leg Syndrome Foundation: Common Questions
- National Institute of Neurological Disorders and Stroke: National Institutes of Health: RLS Fact Sheet
- "Human Biochemistry and Disease"; Gerald Litwack; 2008
- "Professional Guide to Diseases: Ninth Edition"; Springhouse Publishing; 2009
- "Doctor's Complete Guide to Vitamins and Minerals"; Mary Dan Eades and Philip Lief; 2002
- National Institutes of Health: Office of Dietary Supplements: Magnesium
