The Effect of Gluten-Free Diet on Thyroid Autoimmunity in Drug-Naïve Women with Hashimoto's Thyroiditis: A Pilot Study.

BACKGROUND: Autoimmune thyroid disease is often accompanied by celiac disease.

OBJECTIVE: The purpose of this study was to investigate whether a gluten-free diet affects thyroid autoimmunity, hypothalamic-pituitary-thyroid axis activity and thyroid function tests in women with Hashimoto's thyroiditis and incidentally found positive anti-tissue transglutaminase antibodies.

METHODS: The study included 34 women with autoimmune thyroiditis divided into two group. The patients belonging to the first one (group A, n=16) complied with the gluten-free diet for 6 months, while the remaining patients (group B, n=18) remained without any dietary treatment. Serum titers of thyroid peroxidase and thyroglobulin antibodies, as well as serum levels of thyrotropin, free thyroid hormones and 25-hydroxyvitamin D were measured at the beginning of the study and 6 months later. Based on thyrotropin and free thyroid hormone levels, Jostel's thyrotropin index, the SPINA-GT index and the SPINA-GD index were calculated.

RESULTS: All patients completed the study protocol. In group B, serum thyrotropin and free thyroid hormones levels, serum 25-hydroxyvitamin D levels as well as the calculated indices remained at the similar levels. The gluten-free diet reduced thyroid antibody titers, as well as slightly increased 25-hydroxyvitamin D levels and the SPINA-GT index. In group A, the impact on TPOAb and TgAb titers correlated with the changes in the SPINA-GT index, whereas the impact on TPOAb with the changes in 25-hydroxyvitamin D levels.

CONCLUSIONS: The obtained results suggest that the gluten-free diet may bring clinical benefits to women with autoimmune thyroid disease.