Effects of micronutriente supplementation in the treatment oh Hashimoto`s autoimmune hypothyroidism

Abstract

Introduction: Hashimoto’s thyroiditis (HT) is the leading cause of autoimmune hypothyroidism, characterized by lymphocytic infiltration and progressive destruction of the thyroid gland, leading to glandular hypofunction. Although levothyroxine replacement therapy is the standard treatment, it does not directly act on the immunological mechanisms of the disease, which motivates the search for complementary strategies such as micronutrient supplementation. Objective: To evaluate the effects of vitamin D, selenium, zinc, magnesium, and vitamin A supplementation in patients with HT, analyzing their impact on hormonal and immunological parameters. Methods: A systematic literature review was conducted in the PubMed database, including clinical trials and case-control studies published between 2015 and 2025 in English, Portuguese, and Spanish. Eligible studies included patients with laboratory-confirmed diagnosis of HT, comparing isolated or combined supplementation with standard therapy versus placebo or no intervention. Results: Vitamin D showed a significant impact on reducing anti-TPO and anti-Tg antibodies, as well as modulating regulatory T cells and decreasing inflammatory mediators. Selenium, particularly in the form of selenomethionine, reduced thyroid autoantibodies, enhanced antioxidant activity, and favored the restoration of euthyroidism in subclinical cases. Zinc was associated with improvements in inflammatory and oxidative markers, while co-supplementation with magnesium and vitamin A demonstrated beneficial effects in reducing oxidative stress. Conclusion: Micronutrient supplementation represents a promising adjuvant strategy in the management of HT, with potential to reduce autoimmunity, improve thyroid function, and enhance patients’ quality of life. However, the heterogeneity of the studies reinforces the need for more robust clinical trials, with larger sample sizes and longer follow-up.