Summary: Findings from a small sample study link small intestinal bacterial overgrowth (SIBO) to restless leg syndrome.
Source: American Academy of Sleep Medicine
Small intestine bacterial overgrowth (SIBO) may be more prevalent among patients with restless legs syndrome (RLS), according to preliminary findings from a small, new study.
Results show that SIBO was found in all seven participants who have RLS. In contrast, the prevalence of SIBO in the general population is estimated to be no more than 15%.
“We’ve observed extremely high rates of small intestinal bacterial overgrowth in the RLS group,” said lead author Daniel Jin Blum, Ph.D., D.B.S.M., an adjunct clinical instructor at Stanford Center for Sleep Sciences and Medicine in Redwood City, California.
“Exploring the relationship between RLS and gut microbial health has the potential to open novel avenues for possible detection, prevention and treatment for RLS and other sleep disorders.”
SIBO is a condition in which rare gut-residing bacteria are over-represented in the gut. RLS is a sensorimotor disorder characterized by a complaint of a strong, nearly irresistible urge to move the limbs that is often accompanied by other uncomfortable sensations. These symptoms begin or worsen during periods of rest or inactivity such as lying down or sitting, are partially or totally relieved by movement such as walking or stretching, and occur exclusively or predominantly in the evening or at night.
Low iron in the brain is a key risk factor for RLS. According to the authors, this brain iron deficiency may be secondary to dietary iron deficiency or, potentially, gut inflammation.
Study participants completed questionnaires concerning sleep and SIBO symptoms and took home a fecal collection kit and a SIBO breath test kit. Fecal samples were examined by the University of Minnesota Genomics Center, and SIBO breath samples were evaluated by Aerodiagnostics for hydrogen and methane abnormalities.
Additional study participants continue to be recruited at the Stanford Sleep Center. Further analyses will examine fecal microbial composition, subtypes of RLS iron deficiency, and comparisons with insomnia.
Funding: This study was funded by a Pau Innovation Gift Fund Seed Grant.
The research abstract was published recently in an online supplement of the journal Sleep and will be presented Sunday, June 9, in San Antonio at SLEEP 2019, the 33rd annual meeting of the Associated Professional Sleep Societies LLC (APSS), which is a joint venture of the American Academy of Sleep Medicine and the Sleep Research Society.
Restless Leg Syndrome: Does It Start With A Gut Feeling?
Introduction Emerging research links gut microbial health with sleep. One common sleep disorder in which the microbiome may play a role in restless legs syndrome (RLS). While the pathogenesis of RLS is not fully understood, a relative state of brain iron deficiency has been described in patients with RLS and appears to induce changes in several pathways (adenosinergic, glutamatergic and dopaminergic) known to be involved in the disease. Insufficient iron may be secondary to dietary iron deficiency or, potentially, gut inflammation. We hypothesized that small intestinal bacterial overgrowth (SIBO), a condition associated with gut dysbiosis (i.e., normally rare gut-residing bacteria are over-represented in the gut), is associated with RLS and may moderate the observed inter-patient variability in serum iron availability.
Methods Participants are being recruited at the Stanford Sleep Center for three groups: RLS and low peripheral iron stores (<50ng/mL and/or transferrin saturation <18%), RLS and normal peripheral iron stores, and insomnia (control). Participants complete questionnaires concerning sleep and SIBO symptoms and are sent home with a fecal collection kit (Fecal Swab Collection and Preservation System, Norgen Biotek) and a SIBO kit (SIBO Home Breath Test Kit, Quintron). Fecal samples are assayed by the University of Minnesota Genomics Center with microbial community profiling evaluated by 16S ribosomal RNA (16S rRNA) gene sequencing protocols. SIBO breath samples are evaluated by Aerodiagnostics for hydrogen and methane abnormalities.
Results Seven participants diagnosed with RLS (3 men, 4 women) have thus far completed the protocol. All indicated poor sleep quality (PSQI ≥ 5) and moderate to severe symptoms of RLS (IRLS scores ranging from 13 to 34/40). SIBO was present in all 7 participants (100%) whereas general population rates are estimated to be 6-15%.
Conclusion These preliminary data suggest that SIBO may be more prevalent among patients with RLS. Additional analyses will examine fecal microbial composition, subtypes of RLS iron deficiency, and comparisons with insomnia.
Support (If Any) Pau Innovation Gift Fund Seed Grant