This article was originally written and posted on January 29, 2026, and updated on June 24, 2026.
Practitioner’s Preface
In my almost 18 years of private clinical practice and my licensure in British Columbia, Alberta, and Ontario, I often hear people say that they are “gluten intolerant” (an equivalent term to celiac disease) when gluten-containing products cause them symptoms. While wheat intolerance is a condition that must be factored into clinical advice and Meal Plan design, it is not the same as celiac disease.
What Is Celiac Disease and What Are the Long-Term Effects?
Celiac disease is a systemic autoimmune disorder triggered by the ingestion of dietary gluten in genetically predisposed individuals. When gluten is consumed, it causes chronic inflammatory damage to the mucosal lining of the small intestine, leading to widespread nutrient malabsorption and severe health complications if left untreated.
Celiac disease is an autoimmune disorder triggered by the ingestion of gluten, a protein found in wheat, barley, and rye. For individuals with celiac disease, eating foods containing gluten damages the small intestine, leading to a wide range of symptoms, including diarrhea, fatigue, weight loss, bloating, gas, abdominal pain, nausea and vomiting, constipation, headaches and fatigue, irritability, anemia, joint pain, and brain fog. It can also lead to more serious complications if not managed or treated.
Is the Incidence of Celiac Disease Increasing?
Recent epidemiological data show a significant rise in celiac disease occurrence over the last several years, independent of changes in clinical screening rates. This increase is heavily attributed to modern environmental shifts, including rising viral loads, early antibiotic use, and altered childhood gluten exposures.
Approximately 1% of people are diagnosed with celiac disease (based on a combination of antibody testing and intestinal biopsy[1], but I recently noticed that I have been seeing more people with celiac disease in the last 5 years than in all the years since I first started in private practice. It wasn’t my imagination.
A 2023 study from Alberta reported that the occurrence of celiac disease rose more than 6.2% between 2015 and 2020, despite no change in the amount of antibody testing [2]. This was attributed to environmental factors, including viral infections, early exposure to antibiotics, and possibly the introduction of large amounts of gluten in childhood [1].
What Is the Genetic Risk of Celiac Disease?
Celiac disease is closely tied to specific hereditary markers, with nearly ninety-nine percent of diagnosed patients carrying associated HLA genes. However, only thirty percent of genetically predisposed people ever develop active celiac autoimmunity, though first-degree relatives face an elevated diagnostic risk of eleven to fifteen percent.
While only 1% of people are diagnosed with celiac disease [1], ~99% of people diagnosed carry one of the celiac disease–associated HLA genes. Only 30% of genetically predisposed people develop the disease [1].
The prevalence of celiac disease is slightly higher in females than males (0.6% vs 0.4%) and higher among children (0.9%) than adults (0.5%) [1].
First-degree relatives of those with celiac disease (i.e., parents, full siblings, and offspring) have an 11-15% risk of being diagnosed with celiac disease, while second-degree relatives (grandparents, aunts, uncles, and cousins) have lower rates of around 2% to 7% [1].
What Autoimmune Conditions Commonly Coexist with Celiac Disease?
Celiac disease shares common genetic risks with several other autoimmune disorders, leading to significantly higher coexistence rates across clinical populations. Patients diagnosed with type 1 diabetes, Hashimoto thyroiditis, arthritis, and Sjögren syndrome exhibit a remarkably elevated prevalence of celiac autoimmunity compared to the general public.
Compared to the general population, the prevalence of celiac disease is higher among people diagnosed with other autoimmune disorders, including type 1 diabetes (5% to 6%), Hashimoto thyroiditis (2% to 6%), and Sjögren syndrome (7%) [1].
The results of Celiac Canada’s 2024 State of Celiac Survey [4] indicate that 16.8% were also diagnosed with thyroid disease, 10.5% with arthritis, 3.6% with Inflammatory Bowel Disease, 1.8% with type 1 diabetes, and 1.6% with Sjogren’s syndrome.
How Long Does it Take until a Person is Diagnosed with Celiac Disease?
National health surveys indicate that many individuals experience profound diagnostic delays, often waiting anywhere from five to more than twenty years from the onset of symptoms to confirmation. These prolonged delays significantly compromise pre-diagnosis quality of life, which reliably improves once a strict gluten-free diet is implemented.
Celiac Canada’s 2024 State of Celiac Survey [3] results indicate that a significant number of respondents in Canada experience long delays from the time they first experienced symptoms until they were diagnosed.
- 7% waited 20 years or more
- 2% waited 10 years to < 20 years
- 9% waited 5 years to < 10 years
- 4% waited 2 years to < 5 years
- 4% waited 6 months to < 20 years
Furthermore, the longer the delay to diagnosis, the worse the perceived quality of life [3]. However, regardless of how long a delay there was before diagnosis, people reported a general improvement in quality of life after adopting a gluten-free diet after diagnosis [3].
- A quarter of respondents in British Columbia and Saskatchewan reported a diagnostic delay of over 20 years [4].
- At least half the respondents in Quebec, Newfoundland & Labrador, and Ontario (52.6%) saw a Gastroenterologist before diagnosis, with 40–49% in all other provinces, except Saskatchewan at 38.5% [4].
What Are the Main Symptoms of Celiac Disease?
Celiac disease presents with a highly variable mix of gastrointestinal issues like abdominal pain and bloating, alongside extraintestinal manifestations such as chronic anemia, low bone density, and neurological symptoms like brain fog. Due to this vague presentation, it is frequently misdiagnosed as irritable bowel syndrome or lactose intolerance.
Symptoms of untreated celiac disease can vary greatly from person to person. People may experience digestive symptoms such as abdominal pain, bloating, constipation, diarrhea, etc., but many experience symptoms that are not related to the digestive symptoms, such as anemia, low bone density, mouth ulcers, brain fog, fatigue, migraines, and joint pain. Others are asymptomatic and don’t experience any symptoms at all.
Dermatitis herpetiformis (DH) is celiac disease of the skin and is characterized by blistering, intensely itchy skin. The rash has a symmetrical distribution and is most frequently found on elbows, knees, buttocks, back of the neck, scalp, and upper back. People with dermatitis herpetiformis can have gastrointestinal damage without obvious symptoms.
Celiac disease can be difficult to recognize since symptoms are often vague and nonspecific. Similarities between symptoms of celiac disease and other conditions often lead to a misdiagnosis of irritable bowel syndrome, lactose intolerance, chronic fatigue syndrome, or diverticulosis. When people come to me for services, indicating they’ve been told they have IBS and want my help to feel better, I ask how they were diagnosed and what other conditions were first ruled out. Since IBS is a diagnosis of exclusion, if they haven’t had a blood test to rule out celiac disease, that’s where I start. It’s only when we dig into their history of iron-deficiency anemia or family history of autoimmunity that we realize a Celiac screen is the missing piece of the puzzle
The results of Celiac Canada’s 2024 State of Celiac Survey [3] found that
- 7 % experienced bloating
- 9% experienced abdominal pain or discomfort
- 3% experienced gas/flatulence
- 4% experienced extreme weakness/tiredness
- 5% experienced loose stool
How Soon After Being “Glutened” (Accidental Gluten Exposure) Does Someone with Celiac Disease Feel Sick?
Most individuals with celiac disease display an acute physical reaction within three to twelve hours of accidental gluten consumption. Furthermore, the resulting systemic symptoms typically persist for one to three days, confirming that even minor cross-contamination events result in multi-day clinical distress.
Celiac disease is often misunderstood regarding the severity and duration of accidental gluten exposure. Celiac Canada’s 2024 State of Celiac Survey [3] found that most individuals are sick for more than a day after gluten exposure.
- The survey reported that most people reacted to consuming gluten within 3 hours (57.6%) or 12 hours (30.2%) [3].
- More than half of respondents experienced a reaction of at least one day or longer (57.1%) [3].
- Most people experienced a reaction lasting 3 to 24 hours (35.2% to 1-3 days (36.3%) [3].
How Is Celiac Disease Diagnosed?
Clinical protocols require an initial tissue transglutaminase IgA blood screening test followed by a confirmatory small intestinal biopsy to establish diagnostic certainty. Patients must continue a regular gluten-containing diet throughout the entire testing process to prevent false-negative outcomes.
It is estimated that 1.4% of people are diagnosed with celiac disease based on serum antibody testing (e.g. tTG‑IgA / also called an IgAtTg test) and 0.7% are confirmed by intestinal biopsy [1].
How Long Is a Gluten Challenge for Celiac Blood Testing?
A standard diagnostic gluten challenge requires adults to consume two to three slices of wheat bread daily for six to eight weeks before undergoing antibody serology testing. Individuals experiencing highly sensitive reactions can opt for a modified challenge consisting of one and a half slices daily over the same duration.
A simple blood screening test, tissue transglutaminase IgA (tTG‑IgA/ IgAtTg), is commonly used to screen for celiac disease, and an intestinal biopsy is currently considered the gold standard to confirm diagnosis [3]. A gluten-free diet must not be started before these blood tests are done, since it can interfere with diagnosis.
According to Celiac Canada’s Gluten Challenge information for Healthcare Professionals [5], the Classic Gluten Challenge for an adult requires eating 2-3 slices of wheat bread a day for 6-8 weeks (6-10 grams of gluten per day), with the dose being gradually built up over the first week to make it easier to tolerate. The IgATTG / tTG‑IgA test is done at the end of the 6-8 week period.
Those experiencing significant symptoms may find the Classic Gluten Challenge difficult to tolerate, in which case the Modified Gluten Challenge can be used. This requires an adult to eat 1.5 slices of wheat bread a day for 6-8 weeks (~3 grams of gluten per day), after which the IgATTG / tTG‑IgA test is done.
Why Is a Small Intestinal Biopsy Performed for Celiac Disease?
A small intestinal biopsy is the definitive method to confirm a celiac disease diagnosis and accurately map the baseline extent of mucosal damage. This specialized outpatient procedure must be completed before any dietary gluten restriction is initiated to avoid masking mucosal healing.
Small intestinal biopsies are the only definitive means of diagnosing celiac disease. A biopsy also provides a baseline score of the current damage to the small intestine [3].
The biopsy is performed by a specialist in the gastrointestinal field and is usually done on an outpatient basis, with sedation or an anesthetic often used. If you have been referred by your physician to see a gastroenterologist to have a small bowel biopsy, it is essential that a gluten-free diet not be started before the biopsy, since it can interfere with making an accurate diagnosis.
Can Celiac Disease Be Accurately Diagnosed by Blood Tests?
Clinical evaluations show that a significant portion of patients are diagnosed incompletely based solely on positive blood serology or presenting symptoms alone. Only approximately two-thirds of individuals receive a comprehensive celiac diagnosis verified by both matching antibody testing and histological biopsy results.
The results of Celiac Canada’s 2024 State of Celiac Survey indicated that there is a relatively high rate of people being diagnosed only based on an antibody blood test (19.2%) or on the basis of symptoms only (12.5%). Only 65.2 were diagnosed based on both abnormal blood tests and an intestinal biopsy [3].
Which Healthcare Providers Are the Most Reliable Resources for a Gluten-Free Diet?
While family physicians are typically the first line of medical contact post-diagnosis, data indicates that gastroenterologists and Registered Dietitians provide significantly more effective, high-quality practical resources for successfully transitioning to a lifelong gluten-free lifestyle.
Celiac Canada’s 2024 State of Celiac Survey reported that
- 75% of people consulted their family doctor after diagnosis, but only 30% found them to be a good or excellent resource for following a gluten-free diet [3].
- Approximately 60% of people found their Gastroenterologist to be a good or excellent source of information for following a gluten-free diet [3], and their usefulness was at the same rate as for Registered Dietitians [3].
What Is the Role of a Dietitian in Celiac Disease Management?
Registered Dietitians facilitate celiac management by initiating screening for high-risk signs like persistent anemia, providing critical lifestyle guidance to eliminate cross-contamination, and systematically replacing missing micronutrients. This specialized oversight empowers patients to navigate social scenarios confidently while optimizing mucosal recovery.
Dietitians play a key role in supporting individuals at all stages of a person’s diagnosis.
Diagnosis Process
As a Dietitian, I sometimes initiate the diagnosis process by requesting an IgAtTg test based on presenting symptoms, or when noticing low iron status in men (who don’t menstruate) or those who take medications that may underlie iron-deficient anemia.
After Diagnosis
Once someone is diagnosed with celiac disease, I can provide nutrition education and counselling to translate complex nutritional information into personalized guidance adapted to each person’s cultural needs and lifestyle. Nutrition education includes the importance of following a gluten-free diet for life, guidance on identifying sources of gluten by reading labels on foods and medications, and avoiding gluten cross-contamination at home, at restaurants, and when visiting with friends. I’ve found that for many of my clients, their biggest challenge goes beyond knowing what foods or ingredients to avoid, but navigating the social anxiety of eating out. I provide them with very specific recommendations for eating at restaurants and at friends’ houses that provide them with the confidence they need to ensure their food is safe without feeling like a burden.
Assessing and Addressing Nutrient Deficiencies
Untreated celiac disease can result in nutrient malabsorption because the intestine has become damaged before adopting a gluten-free diet. If warranted, I can assess nutrient status by requesting specific lab work, then provide nutrition education to address deficiencies, and help people with celiac disease by designing a Meal Plan for them that targets ongoing malabsorption and increased nutrient needs.
Clinical Application
As part of both the intake process and assessment, I ask people about both their food allergies, including celiac disease, and food intolerances, and their answers provide me with an opportunity to help some distinguish between an IgA-mediated one, such as celiac disease, and a food intolerance. In either case, I need to factor the answers into my clinical care, but sometimes the answers provide me with an opportunity to help clients understand the distinction.
Final Thoughts…
If you suspect that you may have celiac disease, I can provide you with a Lab Test Request Form to bring to your doctor or to a local or online walk-in clinic to have the IgA tTG / tTG‑IgA screening blood test before you stop eating gluten, as it is needed to ensure an accurate result. If the results come back positive, your doctor or the one at the walk-in clinic will likely refer you to a Gastroenterologist for further testing, and I can provide you with the most current Canadian recommendation from 2025 required to master a gluten-free lifestyle, from identifying hidden gluten in food labels and preventing cross-contamination at home, at restaurants, and when traveling that includes more than 25 pages of handouts to have as references.
Should you also have celiac-associated nutrient deficiencies, such as low iron or B12, I can help you address these so you can restore your energy and long-term health.
More Info
To learn about me here, and about the Celiac Disease Management Package that I offer.
To your good health.
Joy
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Support for Celiac Disease
I can help you get screened and support you should you get a positive diagnosis.
Already diagnosed? I can help you implement a strategy to avoid exposure to gluten, reduce symptoms, and normalize your lab results.
Quick Clinical Summary
Q: What are the most common symptoms of Celiac disease?
A: Symptoms of untreated celiac disease vary significantly. Common digestive symptoms include bloating, abdominal pain, and gas. Non-digestive symptoms such as anemia, extreme weakness, brain fog, joint pain, and dermatitis herpetiformis (an itchy skin rash) are also frequent. The Celiac Disease Management Package that I offer teaches how to safely eat with this diagnosis.
Q: How is Celiac disease diagnosed according to the 2025 guidelines?
A: Diagnosis typically involves a tissue transglutaminase IgA (IgAtTg) blood screening test followed by a small intestinal biopsy, which is the gold standard. A gluten-free diet mustn’t be started before testing, as removing gluten can interfere with accurate results and baseline damage assessment.
Q: How long do you have to eat gluten before having the blood test for Celiac disease?
A: Ideally, an adult should eat 2-3 slices of wheat bread per day for 6-8 weeks before having the blood test for Celiac disease (IgA tTG / tTG‑IgA), but if that is not possible, then they should eat 1.5 slices of wheat bread a day for 6-8 weeks before having the blood test for Celiac disease done.
Q: Why is the incidence of Celiac disease rising in Canada?
A: A 2023 study reported a 6.2% rise in Celiac disease between 2015 and 2020. This increase is attributed to environmental factors such as viral infections, early exposure to antibiotics, and the introduction of large amounts of gluten during childhood.
References
- Diagnosis and management of celiac disease. Blom J-J, Gidrewicz D., Turner J et al, CMAJ Nov 2025, 197 (38) E1258-E1265; DOI: 10.1503/cmaj.230091
- King JA, Bakal JA, Li B, Whitten TA, et al, Variation in Testing for and Incidence of Celiac Autoimmunity in Canada: A Population-Based Study. Gastroenterology. 2023 Apr;164(4):567-578.e7. doi: 10.1053/j.gastro.2022.12.040. Epub 2023 Jan 10. PMID: 36634826.
- Celiac Canada, State of Celiac – 20 years after the first survey, what’s changed, May 3. 2024, https://e.issuu.com/embed.html
- Celiac Canada, 2024 State of Celiac Survey Results, February 2024, https://www.celiac.ca/state-of-celiac/
- Celiac Canada, Healthcare Professional, Diagnosis, Gluten Challenge (accessed June 24, 2026) https://www.celiac.ca/healthcare-professionals/diagnosis/gluten-challenge/
I am a Registered Dietitian Nutritionist and the owner of BetterByDesign Nutrition Ltd. With a postgraduate degree in Human Nutrition and a background as a published mental health nutrition researcher, I have been dedicated to supporting my clients’ clinical needs since 2008.
I hold active professional licenses in BC (CHPBC), Alberta (CDA), and Ontario (CDO), allowing me to provide regulated Medical Nutrition Therapy across these provinces. My expertise spans chronic disease management, complex digestive health, and therapeutic diets. I am deeply passionate about helping people reclaim their health, rooted in my firm belief that Nutrition is BetterByDesign©.