Introduction and objective: There is a growing interest in a gluten-free diet (GFD) in the management of various autoimmune diseases, including Hashimoto's thyroiditis (HT). Even medical professionals claim that gluten elimination may improve a patient's treatment. Some studies suggest a relationship between gluten intake and HT development or progression. The aim of the study was to analyze and describe available knowledge regarding the effect of gluten or a gluten-free diet on thyroid autoimmunity in HT with or without celiac disease.
Brief description of the state of knowledge: Potentially applicable records were obtained through review and analysis of the PUBMED (MEDLINE) and Google Scholar database by using the following phrases: 'hypothyroidism gluten', 'Hashimoto gluten' and 'thyroiditis gluten'. If a record focused on the subject by title and abstrakt, the full paper was screened. Authors' scientific achievements and references of eligible records were screened for possibly omitted studies. The review was focused only on human studies.
Discussion: Gluten exclusion might increase the risk of HT development because of the potential nutritional deficiencies related to the low quality of gluten-free products. Gluten intake from crops grown on selenium-depleted soil increases the risk of HT development. Only a few studies suggest that GFD would be beneficial for HT patients, even without the coexistence of CD. The strongest connection between gluten intake and thyroid destruction seems to be based on a mechanism of molecular mimicry between gut and thyroid tissue transglutaminase.
Conclusions: Studies conducted so far do not support the claim that HT patients should eliminate gluten from their diet. In view of the limited number of studies, with major limitations and ambiguous results, a gluten-free diet is not recommended.
Keywords: Hashimoto’s thyroiditis; gluten; hypothyroidism; thyroid functions; thyroid peroxidase antibodies.