Coeliac disease: symptoms, testing and gluten-free living

Coeliac disease is not a food allergy and not an intolerance. It is a lifelong autoimmune condition where gluten makes your own small intestine take damage. About 1 in 100 people have it, and it sits slightly higher in women than in men (PMID 29551598). Yet many walk around for years without a diagnosis.

That happens because the symptoms rarely point at your gut. Often the first sign is an iron level that will not climb, persistent tiredness, or an irregular cycle. Exactly the complaints women bring to the GP, and exactly the ones rarely linked to gluten straight away.

The biggest mistake I see people make: going gluten-free before they are tested. That erases the very clue the test needs. Test first, change later.

What is coeliac disease exactly?

In coeliac disease, gluten switches your immune system against your own gut wall. It attacks the villi, the tiny folds in your small intestine that absorb nutrients. Those villi get damaged and flatten, so you take up less iron, fewer vitamins and other nutrients (PMID 28760445).

Gluten sits in wheat, barley and rye, and therefore in bread, pasta, biscuits and many ready-made products. It is not the gluten itself that makes you ill, but the immune reaction that follows. That is why coeliac disease is an autoimmune condition, not an allergy.

The difference from a wheat allergy or gluten sensitivity is large. How those three relate is explained in the article on the gluten intolerance test and the difference between coeliac disease, allergy and sensitivity. This page is about coeliac disease itself.

How common is coeliac disease, and why more often in women?

Coeliac disease affects roughly 1% of people, and women slightly more than men. A large meta-analysis found a global prevalence of 0.7% based on biopsy, with 0.6% in women against 0.4% in men (PMID 29551598). Many of them do not know it themselves.

That underdiagnosis is the real problem. For every woman with a diagnosis there are several without one, often because their complaints do not seem to point at the gut. A woman with a low iron gets iron tablets sooner than a gluten test.

Why the skew toward women? Autoimmune conditions affect women as a group more often, and coeliac disease belongs in that group. The exact cause is not fully known, but hormonal and immune differences likely play a part.

Who is more likely to get coeliac disease?

Coeliac disease occurs more often in certain groups than average. Think of people with a first-degree relative who has coeliac disease, and people with another autoimmune condition. The combination with an autoimmune thyroid and with type 1 diabetes is especially well known (PMID 27256300).

That does not mean you automatically get coeliac disease if you fall into such a group. It means your chance is higher, and that complaints may be linked to gluten sooner.

If you belong to a risk group and have complaints, that is a reason to weigh coeliac disease. More on the hereditary side is further down.

What are the symptoms of coeliac disease?

The symptoms of coeliac disease vary widely. Some people have belly pain, diarrhoea and bloating. Others have no gut complaints at all, but do have fatigue, a low iron, a skin rash or an irregular cycle. That second group is missed most often.

It helps to separate typical gut complaints from the so-called atypical signals that show up outside the gut. In women, the atypical ones are often the only ones.

That itchy rash is called dermatitis herpetiformis and is the skin form of coeliac disease, with blisters on elbows, knees and buttocks (PMID 27499257). Someone with such a rash almost always has gut damage too, even without belly complaints.

Which signals get overlooked most often in women, and why, is worked out in recognising coeliac disease symptoms in women.

Which blood values show coeliac disease?

Coeliac disease starts with a blood test for antibodies. The main one is anti-tissue-transglutaminase (Anti-TTG, IgA). Endomysium IgA is often measured alongside as confirmation, plus Total IgA to check whether you make enough IgA (PMID 35043426). Without that check, a result can be falsely negative.

The order is not random. Anti-TTG is the first sieve, Endomysium IgA confirms, and Total IgA catches the people who make too little IgA and would otherwise get a falsely normal result.

Here is the big trap: this test only works if you are still eating gluten when your blood is drawn. Go gluten-free first, and the antibodies drop, so the test can read normal when it should not. Keep eating bread until you are tested.

You can have Anti-TTG and Endomysium IgA measured together through the coeliac disease blood test, with Total IgA alongside as a check. How to read such a result, step by step, is in coeliac disease blood test: which values say enough. A positive blood test is then usually confirmed with a gut biopsy by your doctor.

How is the diagnosis confirmed?

A positive blood test makes coeliac disease likely, but does not yet fix the diagnosis. In adults a doctor usually then checks with a gut biopsy whether your villi are really damaged (PMID 28760445). That small piece of tissue is taken during a gastroscopy.

The damage is described in grades, from mild inflammation to fully flattened villi. The stronger that flattening, the more your absorption is disturbed. That explains why two people with the same diagnosis can feel very different.

Keep eating gluten for this too until everything is done. Go gluten-free in between, and your gut already recovers partly, which blurs the picture. Your GP or gastroenterologist decides the order.

Coeliac disease, iron deficiency and fertility: the woman-specific chain

In coeliac disease your damaged villi absorb less iron. That is why an iron deficiency can be the first and sometimes only clue. In studies of people with unexplained anaemia, a small but real share turn out to have coeliac disease (PMID 29689265). Iron tablets that do not work are a classic signal.

Take two women with the same low ferritin of 12. One gets iron tablets and hears nothing more about it. The other is also tested for coeliac disease, because her iron keeps dropping back as soon as she stops. Same value, different story.

That chain runs on. A low iron causes fatigue, and malabsorption can affect your cycle and fertility too. Women with untreated coeliac disease more often have unexplained fertility problems and recurrent miscarriage (PMID 24619876). After a gluten-free diet, that risk often partly recovers.

Why iron stays so stubbornly low in coeliac disease is covered in coeliac disease, iron deficiency and unexplained fatigue. What coeliac disease does to fertility and pregnancy is in coeliac disease, fertility and pregnancy.

It pays to look wider at a low ferritin. What a low ferritin means and how to recognise iron deficiency without anaemia connects directly to this.

Which other shortfalls belong to coeliac disease?

Besides iron, coeliac disease can also disturb the uptake of vitamin B12, folate, vitamin D and calcium. Those shortfalls explain part of the fatigue, and a low calcium and vitamin D can affect your bones over time. Early bone loss occurs more often in untreated coeliac disease.

The pattern is always the same: a damaged gut absorbs less, however well you eat. That is why doctors in coeliac disease often look at several values at once, not only iron.

After a gluten-free diet the villi usually recover and absorption improves gradually. Some shortfalls need topping up in the meantime, in consultation with your doctor.

Is coeliac disease hereditary?

Coeliac disease sits partly in your genes. Almost everyone with it carries the tissue type HLA-DQ2 or HLA-DQ8, and you inherit those genes from your parents. If you have a parent, sibling or child with coeliac disease, your own chance is clearly higher than average, roughly 1 in 10.

Genes alone are not enough. Many people carry HLA-DQ2 or DQ8 and never develop coeliac disease. So there needs to be a predisposition plus something that switches the disease on, and that last part is not fully understood.

What heredity means for you and your family, and who might consider testing, is in is coeliac disease hereditary: what it means for you and your family. Coeliac disease also runs together more often with other autoimmune conditions, such as an underactive thyroid (PMID 27256300).

What does gluten-free living mean?

The only treatment for coeliac disease is a lifelong gluten-free diet. No wheat, barley or rye, and therefore no ordinary bread, pasta or biscuits. If you leave gluten out completely, your villi can recover and your symptoms usually ease. The Voedingscentrum and Thuisarts explain what such a diet looks like in practice.

Eating gluten-free asks for care, because even small amounts count. Cross-contamination through the same bread board, the same pan or the same mixing bowl can keep irritating your gut. Recovery of the villi then often takes months to years.

Gluten-free is therefore not a lifestyle choice in coeliac disease, but a medical necessity. That is a key difference from people who eat gluten-free without a diagnosis, which the NHG does not see as a health gain as long as coeliac disease has not been shown.

And there the test returns. Go gluten-free on your own and feel better, and you still do not know whether you have coeliac disease. Test first, because a diagnosis decides whether you need this diet for life and whether your family is at risk too.

Can you cure coeliac disease?

Coeliac disease does not go away and cannot be cured. What is possible: the complaints and the gut damage settle once you leave gluten out completely. In that sense the treatment is simple and effective, but lifelong.

A stubborn misunderstanding is that a single biscuit does no harm. That is not true. Every time gluten comes in, the immune reaction can damage your gut again, even without you noticing.

That is why a diagnosis matters so much. Someone who knows it is coeliac disease also understands why that one biscuit is not innocent.

What do you do if you suspect coeliac disease?

Do you recognise yourself in a stubbornly low iron, unexplained fatigue or gut complaints that keep returning? Then keep eating gluten and discuss a coeliac test with your GP. They can decide whether an Anti-TTG blood test makes sense and what a result means. My advice stays simple: change nothing about your bread until you are tested.

If you want to have your antibodies measured already, you can test for coeliac disease or pick individual markers through building your own blood test. Do it while you are still eating gluten, and discuss the result with your GP afterwards.

References

1. Lebwohl B, Sanders DS, Green PHR. Coeliac disease. Lancet. 2018;391(10115):70-81. PMID 28760445.
2. Singh P, Arora A, Strand TA, et al. Global Prevalence of Celiac Disease: A Systematic Review and Meta-analysis. Clin Gastroenterol Hepatol. 2018;16(6):823-836. PMID 29551598.
3. Mahadev S, Laszkowska M, Sundström J, et al. Prevalence of Celiac Disease in Patients With Iron Deficiency Anemia: A Systematic Review With Meta-analysis. Gastroenterology. 2018;155(2):374-382. PMID 29689265.
4. Tersigni C, Castellani R, de Waure C, et al. Celiac disease and reproductive disorders: meta-analysis of epidemiologic associations and potential pathogenic mechanisms. Hum Reprod Update. 2014;20(4):582-593. PMID 24619876.
5. Roy A, Laszkowska M, Sundström J, et al. Prevalence of Celiac Disease in Patients with Autoimmune Thyroid Disease: A Meta-Analysis. Thyroid. 2016;26(7):880-890. PMID 27256300.
6. NHG, Thuisarts and Voedingscentrum. Information on coeliac disease, gluten-free eating and blood testing. Available via thuisarts.nl and voedingscentrum.nl.

Every blood test result at Lunara includes a professional assessment by a BIG-registered doctor. For treatment decisions, discuss your results with your GP.