Volume 30, Issue 172, June 2026

The effect of vitamin D supplementation on immune and hormonal parameters in patients with Hashimoto's disease: a review of the literature

Dominika Ruszel^1♦, Emilia Goc¹, Julia Rogała¹, Katarzyna Markuszka¹, Kinga Polityńska¹, Klaudia Samuła¹, Martyna Sarzyńska¹, Mateusz Szabat², Sylwia Lepak¹, Zuzanna Irzyk¹

¹Faculty of Medicine, Collegium Medicum, University of Rzeszów, Rzeszów, Poland
²Clinical Provincial Hospital No. 2, Rzeszów, Poland

^♦Corresponding author
Dominika Ruszel Faculty of Medicine, Collegium Medicum, University of Rzeszów, Rzeszów, Poland

ABSTRACT

Introduction: Hashimoto's disease is the most common cause of autoimmune hypothyroidism. Accumulating research highlights the association between vitamin D deficiency and the pathogenesis of thyroid diseases. This is related to its immunomodulatory effect, through which it can influence the innate and acquired immune responses. This study aims is to evaluate the effectiveness of vitamin D supplementation in patients with Hashimoto's disease based on current clinical trials and meta-analyses. Methods: We reviewed selected literature available in the PubMed. Clinical trials, meta-analyses, systematic reviews and non-interventional studies published between 2017 and 2026 were included. We analysed the effect of supplementation on immunological and hormonal parameters. Results: Analysis of the collected data showed that vitamin D supplementation leads to a significant reduction in anti-thyroid antibody titers (TPO-Ab, TG-Ab). These changes are particularly noticeable when therapy lasts longer than 3 months. The effect on thyroid secretory function remains unclear. Some studies indicate improvements in hormonal parameters (TSH, FT3, FT4) while meta-analyses do not confirm this effect. Vitamin D suppresses inflammation by reducing pro-inflammatory cytokines. It also restores the balance between Th17 and Treg lymphocytes and affects B lymphocytes. Genetic factors, such as vitamin D receptor (VDR) polymorphisms, may modify the response to therapy. Conclusions: Vitamin D supplementation supports the reduction of inflammatory activity in Hashimoto's disease. Therefore, monitoring and balancing its concentration in patients is essential. Further research is needed to determine its impact on clinically relevant parameters and to establish therapeutic doses depending on the patient's genetic profile.

Keywords: Hashimoto’s disease, autoimmune thyroiditis, anti-thyroid antibodies, immunomodulation, vitamin D supplementation

Medical Science, 2026, 30, e108ms3858

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Published: 21 June 2026