What Is Celiac Disease?
Celiac disease is a lifelong autoimmune condition, not a simple food intolerance. In people who have it, eating gluten — the protein found in wheat, barley, and rye — triggers the immune system to attack the lining of the small intestine. Over time this damages the tiny finger-like projections (villi) that absorb nutrients from food.
Because the damage affects how the body absorbs everything, the symptoms reach far beyond the gut. Celiac disease affects roughly 1 in 100 people, yet many go undiagnosed for years because the signs are so varied — and sometimes barely noticeable at all.
A quick but important note: celiac disease is different from a wheat allergy and from non-celiac gluten sensitivity. Only a doctor can tell them apart, and the tests only work while you are still eating gluten.
The Common Digestive Symptoms
The "classic" picture of celiac disease involves the digestive system, and these remain the most recognised signs:
- Diarrhoea or loose, foul-smelling stools that may float (a sign of poor fat absorption)
- Bloating and excess gas
- Stomach pain and cramping
- Constipation — yes, celiac can cause the opposite of diarrhoea
- Nausea or vomiting after gluten-containing meals
- Unexplained weight loss
If you notice these symptoms clustering after meals containing bread, pasta, or cereal, it is worth raising with your doctor.
The Lesser-Known, Non-Digestive Symptoms
Here is what surprises many people: a large share of adults diagnosed today have few or no obvious gut symptoms. Instead, celiac disease shows up elsewhere in the body, which is exactly why it is so often missed:
- Persistent fatigue and low energy — one of the most common complaints
- Iron-deficiency anaemia that does not respond to iron tablets
- Dermatitis herpetiformis — an intensely itchy, blistering skin rash, often on the elbows, knees, and buttocks; it is a specific skin form of celiac disease
- Recurring mouth ulcers
- Joint and bone pain, and reduced bone density over time
- Headaches or "brain fog"
- Tingling or numbness in the hands and feet
- Low mood, anxiety, or depression
- Irregular periods or fertility difficulties
| Symptom type | Examples |
|---|---|
| Digestive | Diarrhoea, bloating, gas, cramps, constipation, nausea |
| Nutritional | Iron-deficiency anaemia, weight loss, low vitamin D and B12 |
| Skin & mouth | Dermatitis herpetiformis rash, mouth ulcers |
| Neurological | Fatigue, brain fog, headaches, tingling in hands/feet |
| Bone & joint | Joint pain, reduced bone density |
| Emotional & reproductive | Anxiety, low mood, irregular periods, fertility issues |
Symptoms in Children vs Adults
Celiac disease can appear at any age, but it often looks different depending on when it strikes.
In children, especially young ones, the gut symptoms tend to dominate: a swollen tummy, diarrhoea, poor appetite, irritability, and — importantly — failure to grow or gain weight as expected. Delayed puberty and dental enamel problems can also be clues.
In adults, the picture is frequently subtler. Many present with fatigue, anaemia, or the skin rash rather than dramatic stomach upset. This is one reason the average adult can go years before receiving a diagnosis.
How Celiac Disease Is Diagnosed
Please do not try to diagnose yourself, and do not cut out gluten before being tested. Removing gluten too early can heal the gut enough to produce a false-negative result, making the condition much harder to confirm.
The standard pathway is straightforward:
- Blood test. Your doctor first checks for specific antibodies, most commonly tTG-IgA (tissue transglutaminase). Raised levels suggest an immune reaction to gluten.
- Intestinal biopsy. If the blood test points toward celiac disease, a gastroenterologist usually takes a small sample from the lining of the small intestine, often via endoscopy, to look for the characteristic villi damage. This remains the gold standard for confirmation in adults.
- Keep eating gluten until testing is complete — both tests rely on your immune system actively reacting.
Symptoms alone cannot confirm celiac disease, because they overlap with many other conditions. Only proper medical testing can give you a definite answer.
What Happens After Diagnosis
There is currently no cure and no medication for celiac disease. The one proven treatment is a strict, lifelong gluten-free diet. The good news is that for most people the gut heals once gluten is removed, symptoms ease, and the risk of long-term complications drops considerably.
Many people also work with a dietitian to make sure they are still getting enough iron, calcium, fibre, and B vitamins, since these can run low both before and after diagnosis.
Living With Celiac: Reading Labels
Once you are diagnosed, everyday shopping becomes a label-reading exercise. Under EU rules, cereals containing gluten are one of the 14 declarable allergens, so wheat, barley, and rye must be named — usually in bold — anywhere they appear, even inside additives and flavourings. A certified "gluten-free" claim legally guarantees under 20 ppm.
The two things to watch for are hidden gluten (in sauces, soups, processed meats, and modified starches) and cross-contamination warnings such as "may contain traces of wheat." If reading every label feels slow, scanning a product with FoodScan flags gluten sources and cross-contamination warnings for you in seconds.
The bottom line: celiac symptoms are wide-ranging and easy to mistake for something else. If several of these signs sound familiar, keep eating gluten and ask your doctor for a blood test — the answer is worth having.
