The Link Between IBS and Restless Leg Syndrome

There are a variety of health problems a person who has IBS is more likely to have than a person who doesn't have IBS. Surprisingly, restless leg syndrome (RLS) is one of them. It doesn't seem to make logical sense—how might it be that a neurological disorder is associated with a gastrointestinal disorder? Let's take a look at what RLS is and what some of the reasons may be for its overlap with IBS.

What Is Restless Leg Syndrome?

RLS is a movement disorder in which a person experiences uncomfortable urges to move their legs. Symptoms typically occur during times of rest or inactivity, particularly in the evening and into the night. These compelling urges are often relieved with movement. It is estimated that RLS affects approximately 7-10% of the population. The disorder affects more women than men, and although it primarily affects adults, it also affects a surprisingly high number of children: one in 10 adults with the syndrome began having symptoms before the age of 10.

For many people, RLS is not a minor irritation. Symptoms of RLS can be strong enough to disturb sleep, which can lead to fatigue and interfere with daily functioning. Some people with RLS also experience depression, concentration, and memory difficulties. At its worst, the exhaustion caused by RLS can negatively impact one's job, family relationships, and social life.

What Is Restless Leg Syndrome Like?

With RLS, the urge to move the legs can range in severity from mildly uncomfortable to downright painful. Words used to describe the urge include uncomfortable, unpleasant, creeping, pulling, and throbbing. Similar sensations in other parts of the body are rarer, but not unheard of. Sensations are most likely to affect both sides of the body, but some people do experience sensations only on one side or the other. Symptoms tend to vary, both in terms of intensity and how often they occur.

Movement can temporarily relieve the unpleasant sensations until the person returns to a state of rest, in which case the sensations resume. In order to get symptom relief, people who have RLS try a variety of things, including jiggling or stretching their legs while sitting, tossing and turning in bed, or actually getting up and pacing the floor. Symptoms may lessen in the wee hours of the morning, allowing for more restful sleep.

RLS symptoms may be worsened after a busy, active day. In addition to evening onset, people with RLS may experience symptoms during prolonged times of sitting, such as car trips, plane rides, and at entertainment venues (e.g., the movies). RLS symptoms can even interfere with the ability to sit restfully while practicing relaxation exercises.

What Causes RLS?

No one knows for sure what causes RLS. Researchers have identified the following as possible contributors to the problem:

• Genetic predisposition
• Problems with the neurotransmitter dopamine
• Problems with the metabolism of iron
• Problems with nervous system motor pathways

RLS can manifest itself secondarily to other health problems. Symptoms can also be triggered or exacerbated by medication side effects, alcohol use, and sleep deprivation. Pregnancy, particularly the last trimester, can be a trigger for RLS symptoms.

The Overlap Between RLS and IBS

Studies are showing that some people who have certain gastrointestinal disorders have a higher rate of RLS, including celiac disease, Crohn's disease, and IBS.

Studies on the overlap of the two disorders indicate that IBS patients are at higher risk for RLS and vice versa. Study estimates indicate that approximately one-fourth to one-third of IBS patients may also have RLS. One small study shed some interesting (but highly preliminary) light on differences among IBS sub-types. The highest overlap of the two disorders occurred in study participants who had IBS-D (62%), with somewhat of a lesser overlap in participants with IBS-mixed (33%) and significantly less overlap in participants with IBS-C (4%).

A slightly larger study on the overlap between the two disorders also provided an interesting result. Study participants who had both IBS and RLS were also more likely to experience symptoms in the upper part of the digestive tract, including stomach pain, nausea, and vomiting.

Why the overlap? Researchers are looking into various theories, including the role of poor iron metabolism, inflammation, central nervous system dysfunction, and small intestinal bacterial overgrowth (SIBO). Of all the theories, SIBO is getting the most attention.

RLS, IBS, and SIBO

A couple of studies have been conducted looking at SIBO as a possible link between RLS and IBS. In the first study of 32 RLS patients, in fact, SIBO was diagnosed in 69% of them. Before we conclude too much from this, though, it is important to note that the SIBO diagnosis was made through the use of breath testing, a method that is somewhat controversial, since its effectiveness has been questioned.

In the second study, 13 IBS patients who tested positive for SIBO using breath testing were treated with the antibiotic rifaximin for a period of 10 days. Following treatment, according to the study, 10 of these patients experienced "at least 80% improvement" in their RLS symptoms. At a later follow-up date, half of these patients reported complete relief from their RLS. As always, we cannot draw firm conclusions from a single small study, but if these positive results can be replicated, there is a possibility treating SIBO may help both disorders.

Researchers are working to find out why there is an overlap between SIBO and RLS. One possibility is that the underlying factors behind the development of RLS also put a person at risk for SIBO. Alternatively, inflammation stemming from SIBO may affect the functioning of neurotransmitters, resulting in RLS symptoms. Another theory is that SIBO is playing a role in the iron metabolism problems associated with RLS.

What to Do If You Have Both IBS and Restless Leg Syndrome

The most important thing to do if you have both disorders is to make sure you tell your healthcare provider. Another thing that both RLS and IBS patients have in common is a reluctance to discuss symptoms for fear that their symptoms will be minimized. If your healthcare provider does minimize your symptoms or attributes them to stress, find a new practitioner.

Although the research on the connection among SIBO, IBS, and RLS is very preliminary, if you yourself feel that SIBO may be an issue for you, ask your healthcare provider about being tested and treated for the condition.

Lifestyle changes may also help. Self-care and a healthy diet can only help both conditions. Both conditions are also likely to benefit from a reduction in alcohol and caffeine. Finally, try investing in a heating pad or hot water bottle, as heat may offer relief from both IBS and RLS symptoms.