Why Iron?
"We know that iron deficiency is involved because every condition that produces iron deficiency, such as anemia or pregnancy, increases the risk of RLS dramatically," says Dr. Richard Allen, a diplomat of the American Board of Sleep Medicine and a founder of the Johns Hopkins Sleep Disorders Center. In fact, based on studies of hospital patients, about 40 percent of people with anemia had RLS and about 20 to 40 percent of pregnant women have RLS.
Another way researchers know that iron plays a role is that patients responded to supplements. "Then when the iron deficiency is corrected, the RLS often remits," Allen says.
For Some, It’s a No-Brainer
Unfortunately some people with RLS have normal iron levels, but researchers say that’s not a reason to discount iron as an underlying cause. Studies indicate that the problem is that the brains of RLS patients may not be able to absorb iron normally.
In another study, Dr. James Connor, a professor and vice chair of neurosurgery at Penn State University in Pennsylvania, and colleagues used magnetic resonance imaging (MRI) and analyzed brain tissue and found that iron levels were low in cells in a particular area of the brain. Additionally, there were not enough receptors to bind to a protein called transferrin that brings iron to and from the cells. Thus, RLS seems to result from a decreased ability of brain cells to acquire iron. This abnormality could be a genetic defect, Connor says.
