Vitamin D and selenium for type 2 diabetes mellitus with Hashimoto's thyroiditis: Dosage and duration insights.

This letter discusses the publication by Feng et al. Iodine, selenium, and vitamin D are closely associated with thyroid hormone production in humans; however, the efficacy of selenium and vitamin D supplementation for type 2 diabetes mellitus (T2DM) patients with Hashimoto's thyroiditis (HT) remains controversial. In the retrospective study we discuss herein, the authors highlighted significant improvements in thyroid function, thyroid antibodies, blood glucose, and blood lipid in T2DM patients with HT following addition of vitamin D and selenium to their antidiabetic regimens, underscoring the value of these supplements. Our team is currently engaged in research exploring the relationship between micronutrients and HT, and we have obtained invaluable insights from the aforementioned study. Based on this research and current literature, we recommend a regimen of 4000 IU/day of vitamin D and 100-200 μg/day of selenium for over three months to six months for patients with HT, particularly for those with concurrent T2DM.