Celiac disease is highly associated with autoimmune thyroid disease. Here’s why testing matters, and how to go about a thorough investigation.
Celiac disease is characterised by an immune response to gluten, causing inflammation, damage to and permeability of the gut wall, amongst many other symptoms.
When the gut wall becomes compromised, gliadin, the protein found within gluten, can enter the bloodstream. Because gliadin resembles thyroid tissue, the immune system can mistakenly produce antibodies that attack the thyroid gland. This is known as molecular mimicry.
Further, the ‘leaky gut’ caused by Celiac disease not only lets gliadin into circulation but also a host of other toxins that can damage the thyroid gland and other tissues.
Glyphosate, heavy metals and other environmental chemicals are examples.
Lastly – because Celiac disease can lead to malabsorption, widespread nutrient deficiencies may impair the thyroid’s ability to produce adequate thyroid hormones.
This is why Celiac disease can contribute to autoimmune thyroid disease and underscores the importance of thoroughly investigating whether you have the condition —or the genetic potential for it—if you have a thyroid disorder.
So what does a thorough investigation look like, and who should seek these tests out?
🌾 Celiac disease is a systemic disorder that affects organs beyond the gut. Although we’re focusing on the thyroid here, it has also been associated with Type 1 diabetes, psoriasis, microscopic colitis, alopecia, vitiligo, autoimmune hepatitis, rheumatoid arthritis and more [Source].
Step 1. Review signs and symptoms
The first place to start is to assess your symptoms. The most common symptoms associated with Celiac disease include:
Diarrhoea, fatigue, rumbling/gurgling noises in the bowel, abdominal pain, weight loss, bloating and gas.
However – a small percentage of people will present with constipation, and some may have latent disease – with no signs or symptoms picked up on screening.
🔍 Liver enzymes – a hidden clue: Did you know that unexplained raised liver enzymes, specifically aspartate aminotransferase (AST) and alanine aminotransferase (ALT), are a common finding in those with Celiac disease, though generally normalise in time on a gluten-free diet? In around 4-20% of cases, a third enzyme, alkaline phosphatase (ALP) may be raised as well. AST, ALT and ALP are all part of the standard liver function tests performed by your GP [Source].
We also want to consider whether there is a family history of Celiac disease in the family, and whether you currently have an autoimmune diagnosis (be it autoimmune thyroid disease, or other).
From here, it’s time to assess your genetic potential for Celiac disease.
Step 2. Genetic testing
Celiac disease is strongly associated with specific human leukocyte antigen (HLA) class II genes, particularly HLA-DQ2 and HLA-DQ8.
Approximately 95% of individuals with celiac disease have the HLA-DQ2 gene, while most of the remaining 5% express HLA-DQ8 [Source].
If you are found to have either of these halotypes, then you have a genetic susceptibility to Celiac disease. However, this does not confirm a Celiac diagnosis, so we now need to look at blood testing to determine whether an immune response to gluten is present.
For more detail on how an autoimmune disease develops/expresses, see my post on the three-legged stool of autoimmunity here.
Step 3. Celiac serology
Celiac serology refers to a set of blood tests used to help diagnose celiac disease by detecting specific antibodies associated with an immune reaction to gluten.
There are three main antibodies that may be tested –
- Tissue transglutaminase antibodies (tTG-IgA)
- Endomysial antibodies (EMA-IgA)
- Deamidated gliadin peptide antibodies (DGP-IgA and DGP-IgG)
However of the above, tTG-IgA are most commonly ordered and have an 89% sensitivity and 96% specificity [Source]. Your doctor may also run a total serum IgA test, which checks for IgA deficiency, as this can affect the accuracy of the antibody tests.
You will need to be on a full gluten-containing diet in the weeks prior to this test, otherwise, there may be a false negative.
🩸 Tip: There are finger prick test kits available you can do at home, to measure antibody and IgA levels, such as the PRIMA Lab Celiac Test.
Step 4. Confirm with biopsy
Finally, to make a Celiac diagnosis, a small bowel biopsy must be performed by a gastroenterologist. This is considered the gold standard and to my knowledge there is no other alternative.
Step 5. Follow up testing
If you have received a Celiac diagnosis, a strict, life-long avoidance of gluten is necessary to manage the condition. You can repeat the antibody tests in time, though it’s likely they will remain elevated for 12 months or longer after starting a gluten-free diet.
Avoiding gluten can lead to significant improvements for those with autoimmune thyroid conditions.
Hope that helps! Testing for celiac disease is definitely a stone worth turning, given the long-term risks associated with undiagnosed disease.
If you need holistic 1:1 support, please book a consult with me here.
Till next time,
Lauren.
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