Vitamin D and Selenium: Review of Clinical Trials of Synergistic Effects on Thyroid Antibody Levels and Disease Progression in Hashimoto’s Thyroiditis

Introduction:Hashimoto's Thyroiditis (HT) is a common autoimmune thyroid disorder caused by genetic predispositions and environmental factors, such as iodine imbalance, selenium deficiency, and stress. It is characterized by chronic lymphocytic infiltration of the thyroid gland, leading to hypothyroidism and the production of thyroid-specific autoantibodies, particularly anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-TG) antibodies. Materials and Methods:This study combined a literature review with clinical trial analysis to evaluate the role of selenium and vitamin D in HT. A systematic approach was used to identify and assess high-quality, relevant evidence. Results:Selenium supplementation reduced TSH levels in patients without thyroid hormone replacement therapy (THRT) and significantly decreased TPOAb and MDA levels, with no impact on fT4, T3, or TGAb. Adverse events were rare and comparable to placebo. Vitamin D deficiency correlated with elevated TSH, anti-TPO, and anti-TG levels, with HT patients showing significantly lower vitamin D levels than healthy controls or hypothyroid patients. Both selenium and vitamin D demonstrated potential immunomodulatory benefits. Conclusions:Selenium and vitamin D supplementation may aid in managing HT by reducing TSH and thyroid antibody levels, emphasizing the importance of addressing micronutrient deficiencies in autoimmune thyroid disorders.