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

Evaluating the Effect of Selenium Supplementation on Thyroid Nodule Volume in Euthyroid Patients Selenium is an essential trace element, which plays a role in regulation of the metabolism of thyroid hormones. This study was designed to evaluate the effect of selenium on the volume of thyroid nodules in euthyroid patients. 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. 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). Selenium supplementation can reduce thyroid nodule volume in euthyroid patients. Selenium; supplementation; thyroid; thyroid volume; thyroid nodule; euthyroid