Why does gluten affect my thyroid? 

When I was first diagnosed with hypothyroidism, I took the medication prescribed by my GP and took it willingly, anything to get rid of the constant and debilitating fatigue. As time passed, I felt better but not without the prescribed medication. I began asking questions and began searching for other ways to improve my health rather than this long term reliance on pharmaceuticals. Like most people I turned to Dr. Google! One of the first messages my then untrained eye came upon was ‘don’t eat gluten’. This advice was everywhere! So, I obediently (and with great difficulty!!) eliminated gluten from my diet. But was it necessary? Let’s take a look:

What is gluten? Gluten is a protein found in all forms of wheat, barley, spelt, rye and oats1, their various byproducts, and additives containing these ingredients. So, it’s everywhere and a staple in many of our daily diets.

Is there a link between gluten and thyroid conditions? Several studies show a strong link between autoimmune thyroid disease (Hashimotos) and gluten intolerance (1, 2, 3, 4). The link is so well established that researchers suggest all people with autoimmune thyroid disease be screened for gluten intolerance, and vice versa (5).

What explains the connection? It’s simply a case of mistaken identity. The molecular structure of gliadin, the protein portion of gluten, closely resembles that of the thyroid gland. When gliadin breaches the protective barrier of the gut, and enters the bloodstream, the immune system responds by destroying it for removal. That is because gliadin doesn’t belong in the bloodstream but gets there through overly permeable intestinal walls, or a ‘leaky gut’. These antibodies to gliadin also cause the body to attack thyroid tissue because they are so similar in structure. In other words, for someone with gluten intolerance every time gluten is ingested, the immune system launches an attack not only against gluten but also against the thyroid gland. This means if you have Autoimmune Thyroid Disorder (AITD) and are gluten intolerant, if you eat foods containing

1 Oats are naturally gluten free, but they contain a protein avendin which is quite similar to gluten. The oats may also be contaminated if processed in the same facility as the gluten containing grains.

gluten, your immune system may attack your thyroid. Even worse, the immune response to gluten can last up to 6 months each time you eat it.

This explains why it is critical to eliminate gluten completely from your diet if you have AITD. There’s no ‘80/20’ rule when it comes to gluten. Being ‘mostly’ gluten-free isn’t going to cut it. If you’re gluten intolerant, you have to be 100% gluten-free to prevent immune destruction of your thyroid.

How do I know if gluten is triggering my thyroid dysfunction? 1. Try a gluten elimination diet Most experts on gluten sensitivity agree the only reliable test for gluten intolerance is a gluten elimination diet. This involves removing gluten from the diet completely for a period of at least 3 weeks, and then adding it back in after that. If symptoms improve during the elimination period, and return when gluten is reintroduced, a diagnosis of gluten intolerance can be made. 2. Ask your doctor about testing for coeliac disease Coeliac disease is a common digestive condition where a person has an adverse reaction to gluten. If someone with coeliac disease is exposed to gluten, they may experience a wide range of adverse effects, including diarrhoea, bloating, abdominal pain, weight loss, failure to grow at the expected rate and malnutrition. There’s a blood test that can test for coeliac disease (although an official diagnosis is usually made by doing a biopsy via an endoscopy). You should not be avoiding gluten from your diet when the blood test is done as this could lead to an inaccurate result. So, if coeliac disease is on the table, you definitely shouldn’t start an elimination diet.

Standard lab tests aren’t as accurate when diagnosing intolerances, as opposed to coeliac disease. They test for antibodies to gluten in the bloodstream. But antibodies in the blood will only be found in cases where the gut has become so permeable that gluten can pass through. This is a relatively advanced stage of disease. Blood tests will miss the many milder cases of gluten intolerance that haven’t yet progressed to that stage. 3. Consider food sensitivity testing There are also food sensitivity tests available, although they’re not always as reliable as an elimination diet.

Does removing gluten work? Many people can improve their hypothyroid symptoms simply by following a diet that eliminates gluten (6). Although autoimmune diseases such as Hashimoto’s can be successfully managed through diet and lifestyle strategies, it’s important to understand they cannot be cured. It’s a case of taming the immune system so it stops attacking the thyroid tissue.

What can I do next? If you think eating gluten may be impacting your thyroid condition, then why not contact one of our clinics and speak to one of our team who can help you to optimise your nutrition to
support your thyroid health. If this involves removing gluten, we can support you to do this by giving you effective strategies and tasty alternatives.

1.Tuhan, H., Işık, S., Abacı, A. et al. (2016). ‘Celiac disease in children and adolescents with Hashimoto thyroiditis’. Turkish Archives of Paediatrics, 51, 100 – 105. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4959737/

2. Hadithi, M., de Boer, H., Meijer, J.W. et al (2007). ‘Coeliac disease in Dutch patients with Hashimoto’s thyroiditis and vice versa’. World Journal of Gastroenterology, 13, 1715 – 1722. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4146952/

3. Ruggeri, R.M., Trimarchi, F., Giuffrida, G. et al. (2017). ‘Autoimmune comorbidities in Hashimoto's thyroiditis: different patterns of association in adulthood and childhood/adolescence’. European Journal of Endocrinology, 176, 133 – 141. https://www.ncbi.nlm.nih.gov/pubmed/27913607

4. Fallahi, P., Ferrari, S.M., Ruffilli, I. et al. (2016). ‘The association of other autoimmune diseases in patients with autoimmune thyroiditis: review of the literature and report of a large series of patients’. Autoimmune Review, 15, 1125 – 1128. https://www.ncbi.nlm.nih.gov/pubmed/27639841

5. Roy, A., Laszkowska, M., Sundström, J. et al. (2016). ‘Prevalence of celiac disease in patients with autoimmune thyroid disease: a meta-analysis’. Thyroid, 26, 880 – 890. https://www.ncbi.nlm.nih.gov/pubmed/27256300

6. Krysiak R et al. (2019). ‘The Effect of Gluten-Free Diet on Thyroid Autoimmunity in Drug-Naïve Women with Hashimoto’s Thyroiditis: A Pilot Study’. Experimental & Clinical Endocrinology & Diabetes, 127, 417 – 422. https://www.ncbi.nlm.nih.gov/pubmed/30060266


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