Coeliac disease, iron deficiency and unexplained fatigue

Iron that stays low despite tablets is a classic signal of coeliac disease. Among people with unexplained anaemia, a small but real share turn out to have coeliac disease (PMID 29689265). Often that low iron is the only clue, without a single gut complaint.

The reason is anatomical. Iron is absorbed mainly in the upper part of your small intestine, exactly where coeliac disease does most of its damage. As long as that gut is damaged, you are mopping with the tap running.

That explains why iron tablets then disappoint. What coeliac disease is exactly is in coeliac disease: symptoms, testing and gluten-free living.

Why does coeliac disease cause iron deficiency?

Coeliac disease damages the villi in the upper part of your small intestine, and that is exactly where iron is absorbed. Less healthy gut surface means less iron uptake, even if you take in enough iron through food or tablets (PMID 28760445). So the deficiency arises not from eating too little, but from poor absorption.

That is a fundamental difference. In iron deficiency from heavy periods, tablets usually help. In coeliac disease, absorption stays the problem, so iron stays low despite all good intentions.

Besides iron, folate and vitamin B12 can also be absorbed less well. Those in turn contribute to anaemia and fatigue.

Iron tablets that do not work: when do you think of coeliac disease?

Think of coeliac disease when your iron stays low despite tablets, or when it keeps returning as soon as you stop. A low iron without a clear cause, with normal periods, is also reason to look further. Coeliac disease then belongs on the list.

A low ferritin is often the earliest sign, before you have anaemia. What a low ferritin means and how to recognise iron deficiency without anaemia connects directly to this.

Coeliac disease and fatigue

Fatigue in coeliac disease comes partly from the low iron, but not only. Shortfalls in B12, folate and vitamin D play a part too, plus the chronic immune reaction itself. That is why the fatigue sometimes persists while your iron is already recovering a little.

That explains a frustrating pattern: your iron creeps up slowly, but you do not feel fit yet. As long as your gut takes in gluten, absorption keeps stalling and the last bit of energy recovers slowly. Only when the gut settles does the floor under your energy return.

Then give it time. Recovery of the villi often takes months, and until then your energy usually lags behind your blood values.

Fatigue is a common complaint with many causes. Besides coeliac disease, your thyroid can play a part, for example. When your thyroid is the cause is in thyroid and fatigue.

If you stay tired despite a normal iron, looking wider makes sense. Which blood values belong to that is in always tired? which blood values to test.

Which blood values do you test?

With treatment-resistant iron deficiency you look at two things at once: your iron status and coeliac disease. For iron status, ferritin, iron and haemoglobin count. For coeliac disease it is Anti-TTG (IgA), and keep eating gluten for that until your blood is drawn.

You can have your iron status tested or choose a broader fatigue panel. If you want coeliac disease alongside, you can test for coeliac disease or pick individual markers through building your own blood test. How to read a coeliac result is in coeliac disease blood test.

What do you do with treatment-resistant iron deficiency?

If your iron stays low despite tablets, discuss with your GP whether a coeliac test makes sense. Do not change your diet beforehand, because then the test becomes unreliable. Which symptoms in women can also point to coeliac disease is in recognising coeliac disease symptoms in women.

The NHG and Thuisarts stress that one low value is not a diagnosis. They look at the pattern: how low, how stubborn and which complaints come with it. Test first, in consultation, and only then draw conclusions.

References

1. 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.
2. Lebwohl B, Sanders DS, Green PHR. Coeliac disease. Lancet. 2018;391(10115):70-81. PMID 28760445.
3. 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.
4. NHG and Thuisarts. Information on iron deficiency, anaemia and coeliac disease. Available via thuisarts.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.