Gluten Intolerance

Everything you need to know about Gluten Intolerance - symptoms, causes, treatment options available in Australia, and when to see a doctor

Dr. Louis J Sisk

BSc(Hons) MBChB MRCS(Glasg) MTrauma

Published: August 23, 2025

What You Need to Know – The Basics

• Gluten intolerance refers to difficulties with gluten—a protein in wheat, barley, rye and similar grains.
• Common symptoms include abdominal discomfort, bloating, fatigue, headache, and joint pain.
• Coeliac disease is the best understood form: an autoimmune reaction damaging the small intestine.
• Non-coeliac gluten sensitivity (NCGS) causes similar symptoms but does not involve autoimmune damage and lacks clear diagnostic tests.
• While not usually life-threatening, untreated coeliac disease may lead to serious complications.
• A gluten-free diet is the mainstay of symptom management.

Overview

Gluten intolerance affects people differently depending on the underlying mechanism:

Coeliac Disease

In individuals with coeliac disease, gluten triggers an autoimmune response. The immune system attacks the lining of the small intestine, reducing nutrient absorption. This reaction is linked to genetic markers—namely HLA-DQ2 and HLA-DQ8—which present fragments of gluten (gliadin) to immune cells and set off inflammation ¹.

Non-Coeliac Gluten Sensitivity (NCGS)

NCGS does not involve the same autoimmune process and causes no intestinal damage. Symptoms arise without coeliac disease or wheat allergy and are diagnosed mainly by excluding these conditions and observing symptom relief on a gluten-free diet ²³.

Statistics and Prevalence in Australia

Coeliac Disease

• Around 1 in 70 Australians (about 1.4%) have coeliac disease, yet 80% remain undiagnosed ⁴⁵⁶.
• Prevalence estimates from clinical data suggest 1.2% in adult men and 1.9% in adult women ⁷⁸.
• This underdiagnosis means many live with the condition unknowingly, risking long-term complications ⁵⁶.

Self-Reported Gluten/Wheat Sensitivity

• Approximately 13.8% of Australians report non-coeliac wheat sensitivity or gluten avoidance ⁷.
• Surveys from 2015 and 2018 consistently found that 14% of respondents reported wheat sensitivity, with around 25% avoiding gluten entirely, despite few having coeliac disease ⁹¹⁰.

NCGS in the Western World

• Globally in Western countries, NCGS is estimated to affect 0.6% to 6% of the population ¹¹¹⁰.
• More broadly, prevalence estimates span 0.5% to 13%, but diagnosis remains controversial due to lack of biomarkers ¹⁰³.

Summary Table (Australia)

Symptoms and Clinical Presentation

Coeliac Disease

Symptoms vary widely and may include:

• Gastrointestinal: diarrhoea, bloating, abdominal pain
• Systemic: iron-deficiency anaemia, osteoporosis, fatigue, neurological signs
  If untreated, coeliac disease can lead to infertility, elevated risk of certain cancers, and other autoimmune conditions ¹.

NCGS

Symptoms overlap with coeliac disease and may include:

• GI symptoms: abdominal discomfort, bloating, bowel changes
• Extra-intestinal: fatigue, headaches or “brain fog”, joint aches, subtle neurological symptoms ².

Red-Flag Symptoms

Immediate medical attention is needed for:

• Severe abdominal pain
• Unexplained weight loss
• Persistent diarrhoea
• Alert your doctor if symptoms escalate or concern you.

Causes and Risk Factors

Coeliac Disease

• Genetics: HLA-DQ2 or HLA-DQ8 are present in most people with coeliac disease ¹.
• Family history: First-degree relatives have a higher risk, especially children (~10 times higher) [^7][^20].
• Environment: Factors like timing of gluten introduction and gut infections may influence onset [^20].

NCGS

• The exact mechanism is unclear. Some may react to gluten, while others may respond to FODMAPs or other wheat components ¹⁰³¹².
• Diagnosis is complicated, as reactions may arise from psychological expectations (the "nocebo effect") rather than gluten itself ¹².

Diagnosis (Australia)

Coeliac Disease

1. Blood tests for tissue transglutaminase (tTG-IgA) and related antibodies.
2. Upper endoscopy with duodenal biopsy while still consuming gluten gives a definitive diagnosis ¹.

NCGS

• Exclude coeliac disease and wheat allergy first.
• Symptom relief on a gluten-free diet supports NCGS, but no reliable biomarker exists.
• A double-blind, placebo-controlled gluten challenge is the gold standard, but rarely practical in clinical settings ¹³.

Treatment Options in Australia

Coeliac Disease & NCGS

• Strict lifelong gluten-free diet (avoid wheat, rye, barley).
• Medicare may cover diagnostic testing.
• PBS may assist with costs of some gluten-free food, though many products remain out-of-pocket.
• Regular follow-up with a dietitian ensures nutritional adequacy and helps with everyday strategies like dining out ¹⁰[^7].

Supportive Living

• Connect with support groups and online communities.
• Work with healthcare practitioners to manage symptoms and mental wellbeing.
• Emphasise nutritional adequacy—ensure substitutes offer fibre, vitamins and minerals.

Living Well with Gluten Intolerance

• Keep a food and symptom diary.
• Access education—understand food labels, cross-contamination, and safe alternatives.
• Involve family and friends in your dietary preferences to build a supportive environment.
• Manage stress, stay active, and prioritise sleep—overall wellness improves tolerance and resilience.

Prevention / Early Action

• Coeliac disease cannot be prevented, as it's genetically based.
• But early diagnosis prevents long-term harm.
• In families with coeliac disease, consider screening for first-degree relatives [^20].
• Stay alert to persistent symptoms and seek medical advice early.

When to Seek Help Now

Don’t hesitate to contact your GP if you experience:

• Severe abdominal pain
• Unintended weight loss
• Chronic diarrhoea
• New or unexplained systemic symptoms (e.g. fatigue, anaemia)

For emergencies involving intense pain or dehydration, dial 000 immediately.

Key Takeaways

• Coeliac disease affects about 1.4% of Australians, yet remains widely underdiagnosed.
• A significant proportion (~14%) report gluten or wheat sensitivity—usually without a medical diagnosis.
• Strict diagnosis is essential; don’t self-diagnose—symptoms may stem from other causes like IBS or FODMAP triggers.
• A gluten-free diet, paired with professional support, can help many live well.

References