Many people can experience extreme inflammation in different areas of the body which is driven by foods consumed. This can be a major driver of inflammation but commonly missed - but not all food reactions are the same.
Understanding the difference between:
• Food allergy
• Coeliac disease
• Food intolerance
• Food sensitivity
Although symptoms can overlap, the underlying mechanisms are very different.
Food Allergy
A food allergy is an immune-mediated reaction to a specific food protein.
Most classic food allergies are IgE-mediated, meaning the immune system produces Immunoglobulin E (IgE) antibodies against a particular food.
When that food is consumed, the immune system releases histamine and other inflammatory mediators.
Common Food Allergens
• Peanuts
• Tree nuts
• Shellfish
• Fish
• Egg
• Milk
• Soy
• Wheat
Symptoms of Food Allergy
Symptoms typically occur within minutes to two hours of ingestion and may include:
• Hives
• Swelling of lips, tongue, or throat
• Itching
• Vomiting
• Wheezing
• Drop in blood pressure
• Anaphylaxis
Food allergies can be life-threatening and require urgent medical care. Many individuals carry an adrenaline auto-injector (EpiPen).
Alpha-Gal Syndrome (Delayed Mammalian Meat Allergy)
One important exception to the “immediate reaction” rule with food allergies is alpha-gal syndrome.
Alpha-gal syndrome is a type of IgE-mediated allergy to a carbohydrate molecule called galactose-α-1,3-galactose, found in mammalian meat (such as beef, lamb, pork). It is often triggered after a tick bite.
Unlike most food allergies:
• Symptoms may occur 3–6 hours after eating meat
• Reactions can be delayed and harder to recognise
• Symptoms may include hives, abdominal pain, diarrhoea, or even anaphylaxis
Because of the delayed onset, alpha-gal syndrome can be difficult to identify without proper testing.
If delayed allergic-type reactions occur after consuming mammalian meat, medical assessment is essential.
If you suspect you are reacting to mammalian meat we provide testing for Alpha-Gal Syndrome
Coeliac Disease
Coeliac disease is an autoimmune condition triggered by gluten in genetically susceptible individuals.
Gluten is a protein found most commonly in:
• Wheat - including spelt, kamut, semolina, einkorn
• Barley
• Rye
When someone with coeliac disease consumes gluten, their immune system mounts an abnormal response that attacks the lining of the small intestine.
Many foods are commonly contaminated with gluten eg. oats. Please contact us for more information with regards to this
How Coeliac Disease Works
Coeliac disease does not involve IgE antibodies and does not cause immediate allergic reactions such as hives or anaphylaxis.
Instead, it is a T-cell–mediated autoimmune reaction.
Here’s what happens:
1. Gluten is broken down into fragments (including gliadin).
2. In genetically susceptible individuals (HLA-DQ2 or HLA-DQ8), the immune system reacts abnormally.
3. The immune system attacks an enzyme called tissue transglutaminase (tTG).
4. This results in inflammation and damage to the intestinal villi.
The villi are tiny finger-like projections in the small intestine responsible for nutrient absorption.
Over time, damage to the villi can lead to:
• Malabsorption
• Iron deficiency
• B12 and folate deficiency
• Fatigue
• Weight loss
• Diarrhoea
• Bone density loss
• Systemic inflammation
Why Coeliac Disease Is Different From Wheat Allergy
It’s important to distinguish between:
• Coeliac disease (autoimmune)
• Wheat allergy (IgE-mediated allergy)
Wheat allergy can cause immediate symptoms such as:
• Hives
• Swelling
• Wheezing
• Anaphylaxis
Coeliac disease does not cause immediate histamine reactions.
Instead, the damage occurs gradually through chronic immune activation.
Diagnosis
Coeliac disease should always be diagnosed medically.
Testing may include:
• Tissue transglutaminase (tTG-IgA) antibodies
• Total IgA levels
• Endomysial antibodies
• Genetic testing (HLA-DQ2 / HLA-DQ8)
• Small bowel biopsy (in many cases)
Important: Gluten should not be removed from the diet before testing, as this can affect results.
A Note on Non-Coeliac Gluten Sensitivity
Some individuals experience symptoms with gluten consumption but test negative for coeliac disease and wheat allergy.
This is referred to as non-coeliac gluten sensitivity, and the mechanism is still being researched.
Food Intolerance
Food intolerance occurs when the body has difficulty digesting or adequately processing specific components of food.
Unlike food allergy, food intolerance does not involve an IgE-mediated immune reaction.
Instead, symptoms typically arise from impaired digestive enzyme capacity, suboptimal stomach acid production, or impaired bile flow.
Common Types of Food Intolerance
Lactose Intolerance
Results from reduced lactase enzyme activity in the small intestine, leading to poor digestion of lactose (milk sugar).
Fructose Malabsorption
Occurs when fructose transporters in the small intestine are unable to effectively absorb fructose, resulting in fermentation and gas production.
Fat Intolerance
May be associated with impaired bile flow or reduced pancreatic lipase production, leading to difficulty digesting dietary fats.
Protein Intolerance
Can occur with low stomach acid (hypochlorhydria) or reduced protease activity, impairing protein breakdown.
Food intolerances are typically dose-dependent, meaning symptoms often relate to the quantity consumed. They are not life-threatening but can significantly impact quality of life if not properly addressed.
If any part of this system is impaired, incomplete digestion can occur.
Undigested food may ferment in the colon, producing:
• Bloating
• Gas
• Abdominal pain
• Diarrhoea
• Reflux-like symptoms
Supporting Digestive Function
In some cases, targeted digestive support may improve tolerance. This can include:
• Digestive enzyme supplementation
• Supporting stomach acid production where appropriate
• Addressing bile flow
• Investigating underlying gut inflammation or dysbiosis
Simply adding enzymes without assessing underlying drivers may provide short-term relief, but identifying and addressing contributing factors often leads to more sustainable improvement.
Food Sensitivities
The term food sensitivity is often used when symptoms occur after eating certain foods but:
• IgE allergy testing is negative
• Coeliac disease has been excluded
• No clear enzyme deficiency is identified
Symptoms may be delayed even days later and can include:
• Digestive discomfort
• Fatigue
• Brain fog
• Headaches
• Joint pain
• Skin flares
Unlike food allergies, sensitivities are not typically life-threatening, and reactions may be dosedependent or cumulative.
How We Assess Food Sensitivities
There is currently no universally accepted diagnostic test for food sensitivities.
For this reason, assessment is based on a structured, multi-layered approach which may include:
1. Detailed Food & Symptom Diary
Tracking intake and symptom patterns over time remains one of the most valuable tools for identifying potential triggers.
2. Structured Elimination & Reintroduction
Temporarily removing suspected trigger foods and systematically reintroducing them under guidance.
3. IgG4 + Complement (C3d) Testing (Where Appropriate)
Some advanced panels measure:
• Food-specific IgG4 antibodies
• Complement activation fragments such as C3d
The presence of IgG4 reflects immune exposure to a food. When complement activation (C3d) is also measured, it may provide additional insight into immune complex activity.
However:
• These tests are not diagnostic on their own
• Results must always be interpreted alongside symptoms and clinical history
• They are used as an adjunct tool rather than a standalone diagnosis
In some individuals with gut dysfunction or increased intestinal permeability, IgG patterns may help guide a structured elimination trial.
Why Gut Health Is Often Involved
When the gut lining is inflamed or disrupted, digestive enzyme production and barrier function may decline.
This can increase:
• Food reactivity
• Histamine responses
• Digestive discomfort
Addressing underlying gut dysfunction may improve tolerance over time in some individuals.
When to Seek Medical Assessment
Urgent medical attention is required if symptoms include:
• Difficulty breathing
• Throat swelling
• Severe vomiting
• Collapse
How We Can Help
Gut Health Clinic Australia provides:
• Structured digestive assessment
• Microbiome testing
• Support for enzyme insufficiency
• Elimination and reintroduction guidance
• Personalised gut repair protocols
If you experience ongoing food-related symptoms, a structured evaluation can help clarify the underlying mechanism.
Sources
Boyce, J. A., et al. Guidelines for the diagnosis and management of food allergy in the United States. Journal of Allergy and Clinical Immunology.
https://pubmed.ncbi.nlm.nih.gov/21134576/
Lebwohl, B., Sanders, D. S., & Green, P. H. R. Coeliac disease. The Lancet.
https://pubmed.ncbi.nlm.nih.gov/25956012/
Lomer, M. C. E. Food intolerance and gastrointestinal disease. Alimentary Pharmacology &
Therapeutics.
https://pubmed.ncbi.nlm.nih.gov/19508464/
Canadian Society of Allergy and Clinical Immunology. IgG testing for food intolerance is not recommended.
https://pubmed.ncbi.nlm.nih.gov/29573552/
