Restless Leg Syndrome: Causes, Symptoms, and Treatment

Restless legs syndrome (RLS) is a neurological condition that affects up to 10% of the population; women are more commonly affected than men. This condition causes an unpleasant urge to move the legs. The condition tends to become more noticeable in the evening and can significantly impact sleep. The cause of restless legs is still being investigated, but family history, genetics, and iron deficiency are all thought to contribute. Conventional treatments for RLS include medications that may have side effects such as drowsiness, dizziness, and headaches, and, in some cases, these medications can lead to increased symptoms of RLS over time.

This article will discuss a functional medicine approach to managing RLS.

[signup]

What is Restless Legs Syndrome?

RLS, also known as Willis-Ekbom disease, is categorized as a neurological sensory disorder and a sleep disorder.

People with RLS have an overwhelming desire to move their legs. The symptoms usually become more noticeable as the day progresses and are most noticeable in the evening or when trying to sleep. Movement can sometimes relieve the symptoms, but often the relief is only temporary, and the urge to move the legs returns.  

One of the most challenging aspects to manage is that RLS commonly interferes with sleep. The urge to move the legs can prevent falling asleep or make it very difficult to go back to sleep if awoken. This sleep disruption can lead to daytime sleepiness, difficulties at work or school, cognitive challenges, relationship difficulties, and mood changes.  

Up to 10% of the American population, more commonly women, may have RLS. Although it can be diagnosed at any age, the symptoms appear to be more severe in the middle-aged and older.

What Does Restless Leg Syndrome Feel Like?

Patients with RLS describe the feelings in their legs as "aching, throbbing, pulling, itching, crawling, or creeping." These sensations are partially or totally relieved when the legs are moved or stretched. Symptoms are usually more noticeable at night, especially when trying to rest or sleep. The condition can cause significant sleep disruption.

The sensations are usually limited to the legs - it is unusual for them to affect the arms or upper body.

The condition is usually progressive. The severity of the symptoms can change daily and may occur only once or twice a week in moderate-to-severe cases or more than twice a week in severe cases. There may also be periods of remission or spontaneous improvement for weeks or months.

Diagnosing Restless Leg Syndrome

The International Restless Legs Syndrome Study Group has published five diagnostic criteria for RLS:

1. An urge to move the legs, usually, but not always, accompanied by or felt to be caused by uncomfortable and unpleasant sensations in the legs.
2. The urge to move the legs and any accompanying unpleasant sensations begin or worsen during rest or inactivity, such as lying down or sitting.
3. The urge to move the legs and any accompanying unpleasant sensations are partially or totally relieved by movement, such as walking or stretching, at least as long as the activity continues.
4. The urge to move the legs and any accompanying unpleasant sensations during rest or inactivity only occur or are worse in the evening or night than during the day.
5. The above are not solely accounted for as symptoms primary to another medical or behavioral condition (e.g., myalgia, venous stasis, leg edema, arthritis, leg cramps, positional discomfort, habitual foot tapping).

What Causes Restless Legs Syndrome?

It is unknown exactly what causes RLS. There may be dysfunction in part of the brain (substantia nigra) that produces the neurotransmitter dopamine and controls our movements. Low iron levels in the substantia nigra are also thought to be a strong contributor to RLS.

A majority of cases of RLS are called primary or idiopathic (a condition in which the cause is unknown). Genes and family history are thought to play a role, and some recently studied genes are associated with iron metabolism and dopamine pathways.

RLS may also be secondary to other causes, including:

• Iron deficiency
• Nutrient Deficiencies
• Thyroid Disease
• Kidney disease requiring hemodialysis
• Nerve damage (e.g., diabetic neuropathy)
• Pregnancy
• Spinal cord injury
• Multiple sclerosis
• Spinal anesthetic
  

Several medications are known to promote or worsen RLS, including:

• Anti-nausea drugs like metoclopramide (e.g., Reglan)
• Antipsychotic drugs like haloperidol (e.g., Haldol)
• Antidepressants like fluoxetine (e.g., Prozac)
• Allergy medications like diphenhydramine (e.g., Benadryl)
  

Research is also ongoing to evaluate other possible contributors to RLS, including:

• Celiac disease, possibly due to its contribution to iron deficiency
• Irritable bowel syndrome (IBS) and small intestinal overgrowth (SIBO)
• Crohn's disease
• Thyroid dysfunction
• Suboptimal vitamin D
• Micronutrient imbalances

• Excess zinc has been found in the blood of patients with RLS, as have several other trace metals like copper, magnesium, selenium, and calcium

Functional Medicine Labs to Test for Root Cause of Restless Legs Syndrome

The first step when dealing with restless legs is to see a qualified healthcare provider for a complete history, family history, and physical exam.  

An essential piece of the history is obtaining blood donor status, as those who routinely donate blood may have a greater risk of iron deficiency and possibly RLS.  

Another vital piece of medical history is a medication review. Medications, as described above, can promote or exacerbate RLS.

It is essential to rule out other causes of abnormal leg sensations or movements, such as akathisia, nocturnal leg cramps, or neuropathy.

Conventional Tests

Standard lab tests that may already have been ordered include:

• CBC with differential (to assess for anemia)
• Kidney panel (to assess for kidney disease)
• Iron and TIBC (to assess for iron deficiency)
• Ferritin (to assess for low iron stores)
• Liver panel (to assess for liver dysfunction that may contribute to bleeding or disruptions in the iron metabolism pathway leading to iron deficiency)

Functional Lab Tests

Gut Health

Celiac disease, IBS with SIBO, and Crohn's disease have all been associated with RLS. Tests to evaluate these conditions are:

• ‍Celiac and nutrition panel: This test is a good option because it also tests vitamin D levels, ferritin, iron, transferrin, and other causes of anemia.
  ‍
• SIBO Breath Test: Chronic SIBO can lead to vitamin deficiency and osteoporosis due to poor absorption of nutrients in the small intestine.
  ‍
• CICA and fecal calprotectin: To help diagnose or rule out Crohn's disease.

Thyroid Health

Hypo- and hyper-thyroid conditions have been associated with RLS. Consider a complete thyroid panel to get a comprehensive overview of how the thyroid is functioning.

Vitamin D

Suboptimal levels of vitamin D have been associated with RLS. Vitamin D levels should be measured at baseline and periodically while supplementing to achieve optimal levels.

Micronutrient Levels

Excesses of certain trace nutrients like zinc, copper, magnesium, and selenium have been associated with RLS. The micronutrient panel from Spectracell measures all of these trace nutrients and vitamins that can also be associated with RLS.

Restless Leg Syndrome Management

RLS is a complex disorder with an incompletely understood etiology and pathophysiology. Multimodal approaches aimed at multiple pathways may be necessary to help manage symptoms of RLS.  

Working with your functional medicine provider to specifically address any gut issues, iron deficiency, thyroid issues, vitamin deficiencies, or micronutrient imbalances that were identified during testing is essential.  

Conventional Approaches for Restless Legs Syndrome

The conventional approaches for RLS are well-described and consist of medications called dopamine agonists that work on the body's dopamine system. One of the most unfortunate aspects of dopamine agonists is their initial effectiveness is often short-lived, and continuation of the medication can lead to augmentation (worsening) of restless leg syndrome symptoms. Other conventional approaches include anti-seizure medications like gabapentin enacarbil. Opioids and benzodiazepines are sometimes prescribed.  

Nutrition for Restless Legs Syndrome

There is no specific diet for RLS. However, oxidative stress is hypothesized to play a role in the syndrome as well as iron deficiency. Vitamin C rich foods can facilitate iron absorption in the small intestine. Therefore, a diet rich in antioxidant-containing foods high in iron and vitamin C is reasonable to try.

A whole foods low inflammatory nutrition approach may also help to support overall systemic health and increase nutrients needed for proper muscle function.

What Vitamins May Support Restless Legs Syndrome?

Iron

Based on recent evidence, iron supplementation, even in patients with normal serum iron levels, but a ferritin level less than 75 mg/mL, appears to help manage restless legs symptoms.  

A Cochrane Review from 2019 looked at ten studies of over 400 participants with RLS. The use of iron supplementation, either orally or intravenously, resulted in significant improvements in restless legs symptoms compared to placebo.

Vitamin D

A systematic review and meta-analysis reviewed 36 studies comprising 9590 participants and found that vitamin D was significantly lower in patients with RLS. Vitamin D is thought to support dopamine-producing neurons and increase dopamine levels in the brain.

Vitamins C & E

A small randomized, double-blind, placebo-controlled study of 60 patients with RLS investigated supplementation with vitamins C and E against a placebo and found a significant improvement in restless legs symptoms at the end of the 8-week study in the patients receiving vitamins.

What Herbs May Support Restless Legs Syndrome?

Although more extensive studies are needed, functional medicine practitioners commonly use these herbs to help manage symptoms of RLS or support sleep:

• ‍Valerian Root: Valerian root is especially effective in those with an Epworth Sleepiness Scale score of 10 or greater. According to the Academy of Sleep Medicine, a higher dose of valerian root might be more effective than the 800 mg used in the above study.‍
• Saint John's Wort: In an open-label pilot trial, 21 Willis-Ekbom's disease patients were treated with a concentrated extract of Saint John's Wort at a daily dose of 300 mg over the course of three months. The results showed a reduction in symptoms in 17 of the 21 patients.

Other Modalities That May Support Restless Leg Syndrome

Acupuncture

A recent systematic review and meta-analysis evaluated 18 studies that consisted of 640 patients with RLS who were treated with acupuncture alone or in combination with other related therapies (e.g., cupping or moxibustion) vs. 447 patients with RLS treated with non-acupuncture therapies (control group). The results showed that acupuncture alone or in combination with other related therapies was superior to non-acupuncture therapies across a wide range of measures, including the management of restless leg syndrome and improvements in a RLS rating scale.  

Infrared Light Therapy

Infrared light therapy has many health benefits and shows promise in supporting symptoms of RLS. A small, blinded, randomized controlled trial looked at 60 participants with RLS. Half of the participants were treated with near-infrared light (940 nm wavelength) at four specific acupoints on the lower limb and the entire plantar surface of the foot. The other half were treated at the same acupoints with a sham light. Compared to controls, there was a significant improvement in symptoms of RLS in the patients exposed to near-infrared light.

Massage Therapy With and Without Essential Oils

A systematic review is currently underway to address the important question of whether massage helps manage RLS symptoms. Despite a large study not yet being available, several small studies evaluating the use of massage in supporting symptoms of RLS are encouraging.  

A recent randomized clinical trial evaluated 105 participants with RLS. The treatment groups received a massage with lavender or sweet orange essential oil and experienced a significant improvement in RLS scores compared to the control group that received routine care.

A double-blind, placebo-controlled randomized clinical trial was conducted on 60 patients to evaluate massage with olive oil (intervention) against massage with paraffin (control). The olive oil massage was superior in reducing RLS symptoms compared to the paraffin massage.

Lifestyle Changes for Restless Legs Syndrome

Lifestyle changes are suggested to support RLS; these include:

• Reducing alcohol and tobacco use
• Exercise
• Maintaining a healthy BMI. Patients with obesity or who are overweight are more likely to have RLS.
• Sleep hygiene
• Warm baths, heating pads, ice packs
• Yoga
• Pneumatic compression devices

Summary

RLS is a condition that can cause significant distress and sleep disruptions. Conventional approaches often have undesirable adverse effects and can, paradoxically, worsen RLS symptoms. The cause of RLS is unknown, but iron deficiency is a likely contributor, and studies have demonstrated that iron supplementation may be helpful. Many other approaches, including lifestyle changes, dietary changes, the addition of herbs and supplements, and modalities such as acupuncture and massage, show promise for supporting RLS symptoms.