Food Sensitivities
Adverse reactions to certain foods causing digestive discomfort, inflammation, or other symptoms
TL;DR
Food sensitivity is a real but poorly defined category. Most self-diagnosed cases are not allergy, and IgG food panels have no diagnostic validity.
Overview
Food sensitivity sits between true allergy and simple intolerance. Allergy is IgE-mediated, reproducible, and can be life-threatening. Intolerance is dose-dependent and enzymatic or fermentative — lactose, fructose, FODMAPs. Sensitivity is the grey zone: reproducible symptoms without an identifiable immune or enzymatic mechanism. Non-coeliac gluten sensitivity is the most studied example, and blinded rechallenge studies suggest fructans in wheat, not gluten, explain many cases. The clinical risk is over-restriction: people eliminate dozens of foods based on unvalidated testing, narrowing their diet and worsening the gut symptoms they set out to fix.
Common Symptoms
- •Bloating and abdominal distension
- •Loose stools or urgency after meals
- •Fatigue and brain fog
- •Headache
- •Skin flushing or itching
- •Joint aching
Common Causes
- •Lactose or fructose malabsorption
- •FODMAP sensitivity in IBS
- •Non-coeliac wheat sensitivity
- •Histamine intolerance
- •Bile acid malabsorption
- •Undiagnosed coeliac disease
Root Causes
Visceral hypersensitivity, fermentable carbohydrate load, altered gut microbiota, bile acid malabsorption, enzyme deficiency, and — importantly — nocebo response, which blinded trials show accounts for a substantial share of reported reactions.
How It's Diagnosed
Diagnostic Markers
- Coeliac serology (tTG-IgA with total IgA) while still eating gluten
- Full blood count and ferritin
- Faecal calprotectin if diarrhoea is persistent
- Hydrogen breath testing for lactose or fructose
When to See a Doctor
Seek urgent care for lip or throat swelling, wheeze, or collapse after eating — that is allergy, not sensitivity. See a doctor for weight loss, blood in stool, nocturnal diarrhoea, anaemia, or onset after age 50.
Supplements Studied For This
Peppermint Oil
One of the better-evidenced options for post-meal cramping, provided the capsule is enteric-coated.
Probiotics
Worth a time-limited trial of a studied strain; not a fix for a genuine allergy or coeliac disease.
Diet & Lifestyle
Suggested Pattern
A structured, time-limited elimination followed by systematic reintroduction — the goal is the widest tolerable diet, not the narrowest.
Eat more
- Low-FODMAP staples during a trial: rice, oats, potato, carrot, courgette
- Lactose-free dairy or hard aged cheeses
- Firm tofu, eggs, plain meat and fish
- Gradual reintroduction of fermentable fibres
Avoid
- Open-ended exclusion of whole food groups
- Very high-FODMAP loads during an active trial: onion, garlic, wheat in quantity
- Sugar alcohols such as sorbitol and mannitol
- Alcohol, which increases gut permeability and symptom reporting
Supporting Research
Efficacy of a low-FODMAP diet in adult irritable bowel syndrome: a systematic review and meta-analysis
Efficacy of a Low FODMAP Diet in Irritable Bowel Syndrome: Systematic Review and Network Meta-Analysis
Systematic Review: Noncoeliac Gluten Sensitivity
Re-challenge Studies in Non-celiac Gluten Sensitivity: A Systematic Review and Meta-Analysis
Blood Testing for Sensitivity, Allergy or Intolerance to Food
Frequently Asked Questions
Are IgG food tests useful?
Should I just cut out gluten?
How long should an elimination last?
Who It Affects
Around 20% of adults report adverse food reactions, while confirmed IgE food allergy affects roughly 2-4% of adults.
Reported far more often by women and by people with IBS, anxiety, or a history of restrictive eating.
Quick Facts
- •IgG food panels are not validated and are advised against by every major allergy society
- •Coeliac disease must be excluded before removing gluten
- •Blinded rechallenge is the only reliable way to confirm a trigger
- •Most eliminations can be reversed after 6-8 weeks
Lifestyle Tips
- •Keep a structured 2-week food and symptom diary before eliminating anything
- •Use a time-limited low-FODMAP trial with planned reintroduction rather than open-ended restriction
- •Reintroduce one food group at a time over 3 days
- •Work with a dietitian if more than two food groups are excluded
- •Address sleep and stress — both amplify visceral sensitivity
My Notes
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This information is for educational purposes only. Always consult a healthcare professional before starting any supplement regimen.