Effects of Selenium Supplementation on Thyroid Nodule Volume in Euthyroid Patients: A Randomized Clinical Trial

aims: Evaluating the Effect of Selenium Supplementation on Thyroid Nodule Volume in Euthyroid Patients background: Selenium is an essential trace element, which plays a role in regulation of the metabolism of thyroid hormones. objective: This study was designed to evaluate the effect of selenium on the volume of thyroid nodules in euthyroid patients. method: In this triple-blinded clinical trial, a total of 60 euthyroid patients with benign thyroid nodules (solitary or multinodular goiter) and normal serum selenium were randomly divided into the case and control (n=30 each) groups. The case group received selenium 200 μg/day while the control group received placebo for 3 months. Thyroid ultrasound was used to measure thyroid nodule volume. result: Selenium supplementation (200 µg/day) retained the serum selenium levels of participants in the case group (P=0.251), while, the control group showed a significant drop in serum selenium levels (P=0.007). Moreover, the thyroid volume in case group showed a significant decrease after selenium supplementation (P=0.012); however, a nonsignificant increase was seen in thyroid volume in control group (P=0.832). conclusion: Selenium supplementation can reduce thyroid nodule volume in euthyroid patients. other: Selenium; supplementation; thyroid; thyroid volume; thyroid nodule; euthyroid