Case Study: Resolution of 8-Year Chronic Fatigue, IBS, and Brain Fog Using the Functional Health Matrix

Illustrative composite — not a single patient. This case study is a teaching composite synthesised from anonymised patterns in the published clinical literature and Nutri-Link case-history references. It does not describe a specific identifiable patient seen by Codenutri Ltd or any single practitioner. Names, demographic specifics, and quoted dialogue are constructed for educational illustration. Always work with a registered clinician for individual care. Editorial review by Chris Massamba, Dip CNM, FMCHC.

Patient Presentation

Emma (not her real name), a 38-year-old secondary school teacher from Bristol, presented to the clinic in January 2026 with a constellation of symptoms she described as "my body has been running on empty since 2018."

Her presenting complaints, in her words: "I wake up exhausted. By 2pm I can barely keep my eyes open. My stomach bloats after every meal — I look six months pregnant by evening. My brain feels wrapped in cotton wool. I used to be sharp — now I re-read emails three times. My libido has vanished. I've seen four doctors. All my bloods are 'normal.' One suggested antidepressants. Another said it's probably stress."

Emma's symptom timeline traced back to a severe bout of gastroenteritis during a holiday in Morocco in 2018. She had been treated with two courses of broad-spectrum antibiotics (ciprofloxacin, then metronidazole). The acute infection resolved, but her digestion never fully recovered. Over the following years, the fatigue deepened, the brain fog intensified, and she developed new symptoms: cold intolerance, dry skin, brittle nails, and recurrent mouth ulcers.

She had been told she had "post-infectious IBS" and "probably chronic fatigue syndrome." No therapeutic plan had been offered beyond symptom management.

Initial Clinical Assessment

Using the Stewart Nutrition deficiency symptom reference, I conducted a systematic review by body system:

General: Fatigue +++ (suggesting possible deficiencies in iron, magnesium, B1, B12, B vitamins broadly, and protein-energy). Cold intolerance (iron, thyroid). Muscle wasting noted in upper arms — Emma commented her clothes "hang differently" despite stable weight.

Skin: Dry, scaly patches on elbows and shins (essential fatty acids). Excessive bruising on thighs (vitamin C). Fine downy hair on forearms — lanugo, typically associated with protein-energy malnutrition.

Mouth: Recurrent aphthous ulcers — 2-3 per month (iron, B12, folate). Cracking at corners of mouth — angular cheilitis (iron, B2). Sore, smooth tongue — atrophic glossitis (iron, B12, folate).

Nails: Brittle, flaking, with longitudinal ridging (iron, possibly essential fatty acids).

Musculo-skeletal: Calf muscle pain after minimal walking — intermittent claudication pattern (B1 — thiamine). Generalised muscle aching (magnesium).

Neurological: Brain fog described as "cotton wool thinking" (B12, iron, thyroid). Poor short-term memory. Peripheral neuropathy — tingling in toes (B12, B1, B6).

This systematic review painted a picture of multi-system nutritional deficiency — not from inadequate intake (Emma ate a varied diet), but from malabsorption secondary to post-infectious gut dysfunction and repeated antibiotic exposure.

Her conventional bloodwork showed:

• TSH: 3.1 mIU/L (GP reported "normal" — functional medicine optimal range: 0.5-2.0)
• Ferritin: 22 ng/mL ("normal" — optimal: >50, especially with fatigue and hair loss)
• B12: 298 pg/mL ("normal" — optimal: >500, especially with neurological symptoms)
• Vitamin D: 42 nmol/L ("adequate" — optimal: >75)

Every marker was within the laboratory reference range. Every marker was suboptimal by functional medicine standards.

Functional Health Matrix Assessment

I mapped Emma across all 7 nodes of the EPINUTRI Functional Health Matrix. Each node scored 1 (severely impaired) to 5 (optimal function).

1. Structural Integrity — Score: 3/5 Muscle wasting in upper arms despite adequate protein intake. Exercise tolerance poor — breathless after one flight of stairs. No joint pain or structural pathology. The low score primarily reflected deconditioning secondary to fatigue, not primary structural disease.

2. Defence & Repair — Score: 2/5 Recurrent infections: 4-5 upper respiratory tract infections per year. Slow wound healing. History of antibiotic overuse (4 courses in 3 years). The gut microbiome — the body's largest immune organ — had been repeatedly disrupted. Secretory IgA was likely depressed.

3. Energy Production — Score: 1/5 This was the most impaired node. The fatigue pattern — worse in the afternoon, unrefreshing sleep, exercise intolerance — was classic for mitochondrial dysfunction. The Stewart Nutrition screen revealed multiple cofactor deficiencies (iron, magnesium, B1, B2, B3, CoQ10). Afternoon "crashing" suggested impaired glucose utilisation and possible reactive hypoglycaemia.

4. Biotransformation & Elimination — Score: 2/5 Constipation alternating with loose stools. History of antibiotic exposure suggesting impaired hepatic conjugation pathways. Dry skin suggesting essential fatty acid deficiency — EFAs are required for bile flow and toxin elimination. The liver was struggling.

5. Transport — Score: 3/5 Cold extremities, but normal blood pressure and heart rate. Ferritin at 22 ng/mL was insufficient for optimal oxygen transport. No overt cardiovascular pathology, but subclinical iron deficiency was limiting oxygen delivery to tissues.

6. Communication — Score: 2/5 This was the second most impaired node. The hypothalamic-pituitary-adrenal (HPA) axis showed a flattened cortisol rhythm — low morning cortisol, inadequate afternoon response. Thyroid function was suboptimal (TSH 3.1). Sex hormones were suppressed — oestradiol and testosterone at lower quartile of reference range (common in chronic stress and undernutrition). Melatonin was likely disrupted given the unrefreshing sleep pattern. The brain fog suggested neurotransmitter disruption — serotonin (gut-derived, 90% produced in the gut) and dopamine were both likely affected.

7. Assimilation — Score: 1/5 The root of the cascade. Post-infectious IBS with small intestinal bacterial overgrowth (SIBO) — the clinical picture of bloating within 30-60 minutes of eating was classic for proximal SIBO. Angular cheilitis and atrophic glossitis suggested severe malabsorption of iron and B vitamins. The gut barrier was almost certainly permeable ("leaky gut"), allowing lipopolysaccharides and partially digested food proteins into systemic circulation, driving the immune activation and brain fog.

Total Matrix Score: 14/35 (40%) — severe multi-system functional impairment.

Wheel of Life Assessment

I asked Emma to score herself 1-10 across the eight dimensions of the EPINUTRI Wheel of Life:

1. Nutrition & Diet: 4/10 — "I eat reasonably well, but I'm scared of food because everything makes me bloat." 2. Sleep & Recovery: 2/10 — "I sleep 8-9 hours but wake up exhausted. I never feel rested." 3. Movement & Exercise: 1/10 — "I used to run. Now walking to the car is hard." 4. Stress Management: 3/10 — "Teaching is stressful. I don't have a strategy. I just push through." 5. Relationships & Community: 6/10 — "My partner is supportive. I've withdrawn from friends because I'm too tired." 6. Purpose & Meaning: 7/10 — "I love teaching. It's the only thing keeping me going." 7. Environment & Toxins: 5/10 — "I don't smoke. I drink 2-3 glasses of wine per week." 8. Spiritual Practice: 3/10 — "I don't have one. I used to do yoga. I miss it."

Total Wheel Score: 31/80 (39%) — the wheel was flat. Sleep, movement, and stress management were the most collapsed dimensions.

Functional Testing Ordered

1. GI-MAP (Comprehensive Stool Analysis): To assess gut microbiome composition, identify pathogens, measure digestive function (elastase), inflammation (calprotectin), and immune function (sIgA).
2. Lactulose Breath Test (SIBO): To confirm the clinical suspicion of small intestinal bacterial overgrowth — the likely driver of the bloating, malabsorption, and systemic symptoms.
3. Organic Acids Test (OAT): To assess mitochondrial function (citric acid cycle intermediates), yeast/fungal overgrowth (arabinitol), oxalate metabolism, and neurotransmitter metabolites.
4. DUTCH Complete (Dried Urine Hormone Panel): To map cortisol rhythm, sex hormone metabolism, melatonin, and oxidative stress markers.
5. Advanced Thyroid Panel: TSH, free T4, free T3, reverse T3, TPO antibodies, thyroglobulin antibodies.
6. Full Iron Panel: Serum iron, ferritin, transferrin saturation, TIBC.

Key Findings

GI-MAP: Significantly elevated methane (68 ppm peak, reference <10) confirming intestinal methanogen overgrowth (IMO) — the constipation-predominant variant of SIBO. Pancreatic elastase borderline low at 198 µg/g (reference >200). Calprotectin elevated at 128 µg/g (reference <50) indicating intestinal inflammation. Secretory IgA depressed at 380 µg/g (reference 510-2010) — mucosal immune suppression.

Organic Acids Test: Citric acid cycle intermediates (citrate, aconitate, succinate) at 25-40% of expected levels — mitochondrial energy production severely compromised. Elevated arabinose — yeast overgrowth consistent with antibiotic history. Elevated beta-hydroxybutyrate despite adequate carbohydrate intake — impaired glucose utilisation. Low vanilmandelate (VMA) — reduced catecholamine production.

DUTCH Complete: Flattened cortisol curve with low morning cortisol and absent afternoon rise — HPA axis suppression consistent with chronic stress. DHEA-S in lower quartile. Oestrogen metabolites showing preference for the 4-OH pathway (genotoxic) over the 2-OH pathway (protective) — reduced methylation capacity.

Thyroid Panel: TSH 3.6 mIU/L (optimal 0.5-2.0). Free T4 mid-range. Free T3 at lower quartile — impaired peripheral conversion consistent with inflammation and selenium deficiency. Reverse T3 elevated — T4 being diverted to inactive rT3 rather than active T3. TPO antibodies positive at 78 IU/mL — Hashimoto's thyroiditis.

Iron Panel: Ferritin 18 ng/mL. Transferrin saturation 14%. Confirmed iron deficiency without anaemia — insufficient for optimal mitochondrial function, thyroid conversion, and neurotransmitter synthesis.

The deficiency patterns mapped precisely to the Stewart Nutrition reference: angular cheilitis (B2, iron) → confirmed low iron, borderline B2. Atrophic glossitis (B12, folate, iron) → confirmed all three suboptimal. Calf pain on exertion (B1) → B1 was not tested but the clinical picture and mitochondrial OAT findings strongly suggested insufficiency. Muscle wasting (protein-energy) → despite adequate intake, malabsorption was driving a functional protein deficiency.

Intervention Protocol

Phase 1: Remove and Stabilise (Weeks 1-4)

SIBO eradication protocol:

• Allicin (stabilised allicin from garlic) 450mg twice daily — targets methanogens
• Oregano oil (standardised to 70% carvacrol) 200mg twice daily — broad-spectrum antimicrobial
• Berberine HCl 500mg three times daily — targets bacterial overgrowth
• Partially hydrolysed guar gum 5g daily — prebiotic to support beneficial flora during eradication
• Low-FODMAP diet for 4 weeks to reduce fermentable substrate

Gut barrier support (started immediately):

• L-glutamine 5g twice daily on empty stomach
• Zinc carnosine 75mg twice daily
• Vitamin D3 5,000 IU daily (target: 75-100 nmol/L)

Phase 2: Repair and Replete (Weeks 5-8)

Mitochondrial restoration (following the EPINUTRI Mitochondrial Protocol):

• CoQ10 (ubiquinol) 200mg daily — electron carrier between Complex I/II and III
• Nicotinamide riboside 300mg daily — NAD+ precursor for Complex I
• Magnesium glycinate 400mg at bedtime — required for Mg-ATP complex
• Activated B complex (B1 as benfotiamine 150mg, B2 as R5P 50mg, B3 as niacinamide 500mg, B5 500mg, B6 as P5P 50mg)
• Alpha-lipoic acid 300mg twice daily
• Acetyl-L-carnitine 1,000mg daily

Nutrient repletion:

• Iron bisglycinate 28mg daily with vitamin C 500mg for absorption
• Methylcobalamin (B12) 5,000mcg sublingual daily
• Methylfolate 800mcg daily

Dietary transition: Gradual reintroduction of FODMAPs as tolerated. Emphasis on mitochondrial-supportive foods: grass-fed red meat (carnitine, iron, B12), wild salmon (omega-3, CoQ10), dark leafy greens (magnesium, folate), blueberries and dark chocolate (polyphenols for mitochondrial biogenesis).

Phase 3: Rebalance and Integrate (Weeks 9-12)

Wheel of Life interventions:

• Sleep (target: 2→7): 10pm bedtime with 30-minute wind-down (no screens). Morning light exposure 15 minutes within 30 minutes of waking. Magnesium glycinate at bedtime. Sleep improved from 5.5 to 7.5 hours within 3 weeks.
• Movement (target: 1→5): Walking 15 minutes daily increasing to 30 minutes. Yoga twice weekly. No high-intensity exercise until energy stabilised — forcing HIIT on depleted mitochondria worsens fatigue.
• Stress (target: 3→6): Morning breathing practice (4-7-8 technique, 5 minutes). Boundary-setting at work — no emails after 7pm. Reduced wine from 3 glasses/week to 0 for the protocol period.
• Spiritual (target: 3→6): Restarted yoga practice — not for exercise but for mind-body connection.

Outcomes at 12 Weeks

Symptom resolution: Emma described the change as "I got my life back." Bloating reduced by ~90% — "I can eat a meal and still fit in my clothes." Bowel movements normalised to once daily, formed. Brain fog lifted — "I can read a book again. I read three in the last month." Energy improved from 2/10 to 7/10 — "I wake up before my alarm." Libido returned — "my partner noticed before I did."

Repeat testing at Week 12:

• Lactulose breath test: Methane 12 ppm (down from 68) — SIBO effectively eradicated
• Ferritin: 48 ng/mL (up from 18) — approaching optimal range
• B12: 642 pg/mL (up from 298) — now in optimal range
• Vitamin D: 86 nmol/L (up from 42) — optimal
• TSH: 1.8 mIU/L (down from 3.6) — now in optimal range, T4→T3 conversion improved
• Calprotectin: 32 µg/g (down from 128) — gut inflammation resolved

Functional Health Matrix re-score: 31/35 (89%) — +17 points improvement. Assimilation improved from 1 to 4 (SIBO eradicated, absorption restored). Energy improved from 1 to 4 (mitochondrial function restored). Communication improved from 2 to 4 (thyroid, HPA axis, and neurotransmitter function restored).

Wheel of Life re-score: 67/80 (84%) — +36 points improvement. Sleep: 8, Movement: 6, Nutrition: 8, Stress: 7. The wheel was no longer flat.

Emma's words: "I didn't realise how sick I was until I got better. I had normalised exhaustion. Now I know what normal feels like — and I'm never going back."

Maintenance Plan

• SIBO prevention: Prokinetic (ginger 1,000mg + artichoke 500mg) at bedtime for 3 months to maintain migrating motor complex function
• Mitochondrial maintenance: CoQ10 100mg, magnesium 300mg, B complex ongoing
• Iron maintenance: Dietary focus with monthly menstrual cycle awareness
• Sleep hygiene maintained — the single most protective intervention
• Yoga 3x/week, walking daily
• 6-month follow-up with repeat GI-MAP and OAT

Clinical Pearls

1. Gut first, always. Emma had seen four doctors, none of whom connected her gut symptoms to her fatigue, brain fog, and hormonal disruption. The gut is the entry point for nutrients and the largest immune interface — when it's compromised, every other system suffers. Her entire clinical picture was downstream of post-infectious SIBO and malabsorption.

2. "Normal" labs are not optimal labs. Every one of Emma's conventional blood tests was "normal." Every one was clinically insufficient. Ferritin of 18 produces symptoms. B12 of 298 with peripheral neuropathy demands treatment. TSH of 3.6 with positive TPO antibodies is Hashimoto's requiring intervention. The laboratory reference range is a population statistic, not a therapeutic target.

3. The Functional Health Matrix reveals what single tests miss. The matrix scoring made visible what individual results obscured: seven interconnected systems, all impaired, all traceable to a root cause in Assimilation. The matrix guides treatment sequencing — fix the gut first, then the downstream systems can recover.

4. Stewart Nutrition symptom screening is clinical gold. The systematic body-system review — angular cheilitis → B2/iron, atrophic glossitis → B12/folate/iron, calf claudication → B1 — mapped the deficiency pattern before lab results confirmed it. This is bedside functional medicine: the patient's body tells you what's wrong if you know what to look for.

This case study is for educational purposes and represents a composite of clinical patterns seen in practice. Individual patient factors must guide all treatment decisions. Nutritional interventions should be supervised by a qualified functional medicine practitioner.