Fibromyalgia: Causes, Symptoms and a Functional Medicine Approach

Fibromyalgia is a chronic condition characterized by widespread pain, tenderness, fatigue, sleep disturbance and cognitive symptoms such as difficulty concentrating or “brain fog.” It can significantly affect daily function, emotional well-being and quality of life.

The exact cause of fibromyalgia remains unclear. Research suggests that altered pain processing, nervous-system sensitization, sleep disruption, stress-response dysregulation and several metabolic, nutritional and gastrointestinal factors may contribute to the severity of symptoms.

A functional medicine approach does not assume that every person has the same underlying problem. Instead, it examines the patient’s history, symptom pattern, nutrition, sleep, stress, gut function, metabolic health and possible contributing exposures to develop an individualized support plan.

What Is Fibromyalgia?

Fibromyalgia is a long-lasting disorder that can cause pain and tenderness throughout the body. People with fibromyalgia appear to process painful and non-painful sensory signals differently, resulting in increased sensitivity to discomfort.

Fibromyalgia is not classified as an autoimmune disease. However, it may coexist with autoimmune and inflammatory conditions such as rheumatoid arthritis and systemic lupus erythematosus.

Common Symptoms of Fibromyalgia

Symptoms vary between individuals but may include:

• Widespread musculoskeletal pain and stiffness

• Persistent fatigue or low energy

• Unrefreshing sleep or frequent awakenings

• Difficulty concentrating, impaired memory or brain fog

• Headaches or migraine

• Anxiety or low mood

• Tingling or numbness in the hands and feet

• Facial or jaw pain

• Abdominal pain, bloating, constipation or diarrhea

• Symptoms consistent with irritable bowel syndrome

• Increased sensitivity to touch, sound, light or temperature

• Reduced recovery following physical or emotional exertion

What Causes Fibromyalgia?

There is no single established cause. Fibromyalgia is associated with altered nervous-system signaling and central sensitization, in which pain-processing pathways become more responsive to sensory input.

Potential triggers or contributing factors may include:

• Physical or emotional trauma

• Infection or post-infectious immune activation

• Chronic psychological or physiological stress

• Poor-quality or insufficient sleep

• Hormonal changes

• Nutrient deficiencies

• Gut dysbiosis and digestive dysfunction

• Blood-glucose dysregulation

• Reduced physical conditioning

• Genetic susceptibility

Women are diagnosed more frequently than men, and symptoms may be influenced by menstrual, perimenopausal or other hormonal changes.

Conditions That May Coexist With Fibromyalgia

Fibromyalgia may occur alongside:

• Rheumatoid arthritis

• Systemic lupus erythematosus

• Osteoarthritis

• Ankylosing spondylitis

• Irritable bowel syndrome

• Migraine

• Chronic back pain

• Anxiety or depression

• Chronic fatigue symptoms

• Sleep disorders

• Orthostatic intolerance or autonomic dysfunction

Because these conditions can overlap, a detailed assessment is important before attributing every symptom to fibromyalgia.

Functional Medicine Assessment of Fibromyalgia

1. Gut Health

Research has identified differences in the gut microbiome of people with fibromyalgia. Altered intestinal permeability has also been reported in some patients with fibromyalgia and related chronic pain conditions.

An older study examining small intestinal bacterial overgrowth reported an association between abnormal breath testing and fibromyalgia. Further research is required to determine whether SIBO is a cause, a consequence or an associated finding.

Gut assessment may be particularly relevant when the patient has:

• Abdominal bloating or distension

• Constipation or diarrhea

• Irritable bowel symptoms

• Food-related symptom triggers

• Reflux or impaired digestion

• Previous frequent antibiotic use

• Long-term proton-pump inhibitor use

• Suspected malabsorption

Depending on the presentation, a practitioner may consider a comprehensive stool analysis or SIBO breath test. Testing should be selected according to the patient’s symptoms rather than ordered routinely for every person with fibromyalgia.

2. Nutrient Status

Nutrient deficiencies may worsen fatigue, pain, muscle function, sleep and neurological symptoms without necessarily explaining the complete syndrome.

Nutrients to assess when clinically indicated include:

• Vitamin D

• Vitamin B12 and folate

• Thiamine and other B vitamins

• Iron studies and ferritin

• Magnesium

• Calcium

• Zinc and copper

• Omega-3 fatty-acid intake

• Total calorie and protein intake

Vitamin D deficiency has been reported frequently in patients with fibromyalgia, and an association exists between low vitamin D levels and generalized chronic pain. Vitamin B12 deficiency may also contribute to fatigue, neuropathic symptoms and nonspecific pain.

3. Immune and Post-Infectious Factors

Some patients report that symptoms began after an infection. The clinical timeline may include COVID-19, Epstein–Barr virus or another viral illness. Testing for infection should be based on the history, symptoms and likelihood of an active or clinically relevant process.

An autoimmune assessment may be appropriate when the patient has joint swelling, inflammatory symptoms, rashes, Raynaud phenomenon, mouth ulcers, muscle weakness or other findings that cannot be explained by fibromyalgia alone.

4. Mitochondrial and Cellular-Energy Support

Fatigue, muscle exhaustion and slow recovery may be associated with impaired cellular-energy production, oxidative stress, inadequate nutrient cofactors or blood-glucose instability.

Relevant factors include:

• Magnesium, B-vitamin, iron or carnitine inadequacy

• Reduced antioxidant capacity

• Insulin resistance, diabetes or reactive hypoglycemia

• Inadequate calorie or protein intake

• Loss of muscle mass

• Poor recovery following activity

5. Hormonal and Metabolic Contributors

Assessment may include:

• Thyroid function and thyroid autoimmunity

• Glucose regulation and insulin resistance

• Menstrual or perimenopausal changes

• Cortisol rhythm when clinically relevant

• Parathyroid hormone when calcium abnormalities or other indications are present

• Undernutrition or excessive caloric restriction

6. Sleep and Circadian Rhythm

Unrefreshing sleep is a central feature of fibromyalgia and may amplify pain sensitivity, fatigue, appetite dysregulation and autonomic activation.

The assessment should explore:

• Insomnia or frequent awakening

• Restless legs symptoms

• Snoring or possible obstructive sleep apnea

• Delayed sleep timing

• Irregular sleeping and waking schedules

• Evening light and screen exposure

• Late caffeine intake

• Pain that interrupts sleep

7. Stress Response and Autonomic Regulation

Fibromyalgia may involve central sensitization, heightened pain processing, chronic sympathetic activation and insufficient parasympathetic recovery.

Patients may experience:

• Reduced stress tolerance

• Persistent physiological hyperarousal

• Palpitations or dizziness with standing

• Reduced heart-rate variability

• Trauma-related symptoms

• Difficulty recovering after physical or emotional stress

When standing causes palpitations, weakness or dizziness, orthostatic heart rate and blood pressure can be assessed.

8. Environmental Exposures

A careful history may explore occupational and household exposure to moisture-damaged buildings, chemicals, pesticides or heavy metals. Environmental testing should be considered when there is a credible exposure history rather than based on nonspecific symptoms alone.

Laboratory Assessment

Testing should be individualized, but the initial evaluation may include:

• Complete blood count

• Comprehensive metabolic panel

• Ferritin and complete iron studies

• Vitamin B12 and folate

• 25-hydroxy vitamin D

• Thyroid-stimulating hormone and free thyroid hormones

• Inflammatory markers when indicated

• Fasting glucose, HbA1c and other metabolic markers

• Magnesium or other targeted nutrient assessment

Additional functional testing may include:

• Comprehensive stool analysis for substantial gastrointestinal symptoms

• SIBO breath testing for characteristic bloating, distension or bowel-pattern changes

• Micronutrient or organic-acid testing when nutrient or metabolic dysfunction is suspected

• Diurnal salivary or urinary cortisol testing when circadian information would change management

• Infection testing when supported by the clinical timeline

• Environmental testing when there is documented or probable exposure

Conditions That Should Be Considered Before Diagnosing Fibromyalgia

Fibromyalgia symptoms may overlap with other conditions, including:

• Hypothyroidism

• Iron, vitamin B12 or vitamin D deficiency

• Systemic lupus erythematosus

• Rheumatoid arthritis

• Polymyalgia rheumatica

• Spondyloarthritis

• Inflammatory myopathy

• Other systemic inflammatory disorders

• Sleep apnea

• Restless legs syndrome

• Migraine

• Neurological disorders

• Lyme disease when exposure is plausible

• Post-infectious syndromes

• Anxiety and depression

Functional and Integrative Support for Fibromyalgia

Optimize Sleep and Circadian Health

• Aim for approximately eight hours of sleep when possible.

• Maintain consistent sleeping and waking times.

• Reduce evening lighting.

• Sleep in a dark, cool room.

• Avoid phone and computer screens for one to two hours before bed.

• Avoid caffeine after 11:00 a.m. when it interferes with sleep.

• Finish dinner approximately three hours before bedtime.

• Obtain daylight exposure soon after waking.

• Practise relaxation or slow breathing before sleep.

• Assess and address iron deficiency, particularly when restless legs symptoms are present.

Support the Nervous System and Stress Response

Integrative options include:

• Slow diaphragmatic breathing

• Heart-rate-variability biofeedback

• Meditation or guided relaxation

• Yoga adapted to physical capacity

• Tai chi or qigong

• Acupuncture

• Massage or gentle myofascial work

• Time in nature

• Appropriately paced sensory reduction

These interventions are intended to support autonomic regulation, sleep and pain processing. They do not imply that fibromyalgia is imaginary or purely psychological.

Follow an Anti-Inflammatory, Nutrient-Dense Diet

A Mediterranean-style dietary pattern emphasizes vegetables, fruits, whole-food carbohydrates, legumes when tolerated, extra-virgin olive oil, nuts, seeds and omega-3-rich fish. It also limits refined sugar, alcohol and ultra-processed food.

Helpful principles include:

• Distribute adequate protein across meals.

• Eat a variety of colorful vegetables and fruits.

• Include healthy fats and omega-3-rich foods.

• Maintain adequate fluid and electrolyte intake.

• Use balanced meals to avoid large glucose fluctuations.

• Reduce caffeine if it worsens sleep, anxiety or palpitations.

• Adjust specific foods according to symptoms and tolerance.

If a food-related pattern is suspected, a time-limited elimination followed by structured reintroduction is more informative than permanent, broad food restriction.

Address Gut Dysfunction

When gastrointestinal symptoms are prominent, the functional medicine 5R framework may be used:

1. Remove identified dietary triggers, pathogens or irritants.

2. Replace digestive support when it is genuinely required.

3. Reinoculate with individualized prebiotic or probiotic support.

4. Repair nutritional and intestinal-barrier support.

5. Rebalance sleep, stress, meals and lifestyle.

The plan should be guided by symptoms and relevant findings rather than assuming that every patient has SIBO, Candida overgrowth or intestinal permeability.

Introduce Movement According to Recovery Capacity

Aerobic exercise, strength training, aquatic movement, stretching and mind–body exercise may support pain, fatigue, mood and physical function.

Begin with a tolerable level and progress according to recovery and symptom response. Avoid the cycle of prolonged inactivity followed by excessive activity on a “good day.”

If the patient experiences post-exertional malaise—a delayed and disproportionate worsening lasting for hours or days—activity should be paced within the person’s energy envelope rather than increased according to a fixed schedule.

Correct Nutrient Deficiencies

Basic supplements may include, according to individual need and laboratory findings:

• Vitamin D

• Vitamin B12

• Thiamine or folate

• Iron

• Magnesium

• Omega-3 fatty acids

Consider Targeted Mitochondrial Support

Supplements sometimes considered include:

• Coenzyme Q10

• Acetyl-L-carnitine

• Creatine

• N-acetylcysteine

• Alpha-lipoic acid

• D-ribose

Selection should be individualized according to symptoms, nutritional status, laboratory findings, medication interactions and tolerance. Introducing one intervention at a time helps determine whether it is beneficial.

Complementary Support

Acupuncture may be considered as part of chronic-pain management. Massage and gentle myofascial techniques may support comfort and relaxation. Psychological approaches, including cognitive behavioral therapy and emotional-awareness strategies, may help patients manage stress, sleep disruption and the functional impact of chronic symptoms.

A Practical Order of Support

1. Confirm the diagnosis and exclude important mimics.

2. Determine whether post-exertional malaise is present.

3. Stabilize sleep, hydration, meals and daily activity.

4. Correct confirmed nutrient deficiencies.

5. Address significant gut dysfunction.

6. Support autonomic regulation and pain processing.

7. Add mitochondrial support gradually when appropriate.

8. Investigate infection or environmental exposure when supported by the history.

9. Reassess symptoms and functional capacity every six to eight weeks.

Final Thoughts

Fibromyalgia is a complex condition influenced by interactions between pain processing, sleep, stress physiology, nutrition, gut function, metabolism and physical resilience. A functional medicine approach evaluates these systems together and develops an individualized plan based on the patient’s clinical history, symptoms and relevant findings.

The goal is not simply to suppress pain. It is to identify modifiable contributors, improve sleep and energy, support physical function and help the individual regain a better quality of life.

Book a Functional Medicine Consultation

If you are experiencing persistent widespread pain, fatigue, brain fog, sleep disturbance or digestive symptoms, a comprehensive assessment can help identify the factors that may be contributing to your symptoms and guide an individualized support plan.

Dr. Samar M. Shadly, MD, IFMCP
Consultant Integrative Pulmonologist and Functional Medicine Practitioner
Founder of Radical Wellness—Riyadh, Saudi Arabia
Book a consultation.

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References

1. Centers for Disease Control and Prevention. Fibromyalgia.

2. Siracusa R, et al. Fibromyalgia: Pathogenesis, mechanisms, diagnosis and treatment options update. International Journal of Molecular Sciences. 2021.

3. Minerbi A, et al. Altered microbiome composition in individuals with fibromyalgia. Pain. 2019.

4. Goebel A, et al. Altered intestinal permeability in patients with primary fibromyalgia and complex regional pain syndrome.

5. Lowry E, et al. Dietary interventions in the management of fibromyalgia: a systematic review and best-evidence synthesis. Nutrients. 2020.

6. Macfarlane GJ, et al. The effect of acupuncture on chronic pain.

7. Bernardy K, et al. Efficacy, acceptability and safety of cognitive behavioural therapies in fibromyalgia syndrome.

8. Rossini M, et al. Double-blind, multicenter trial of acetyl-L-carnitine in fibromyalgia patients.