Effect of selenium-enriched yeast supplementation on serum thyroid-stimulating hormone and anti-thyroid peroxidase antibody levels in subclinical hypothyroidism: Randomized controlled trial

Background: In the subclinical hypothyroidism, T4 or T3 levels are normal and thyroid-stimulating hormone (TSH) is slightly high. Selenium deficiency can lead to thyroid dysfunction. The present study aims to investigate the effect of selenium supplementation on the thyroid hormone and anti-thyroid peroxidase antibody (anti-TPO AB) levels. Materials and Methods: In this double-blinded, randomized, placebo-controlled clinical trial, 42 patients with subclinical hypothyroidism were randomly assigned to receive 200 μg selenium or placebo for 8 weeks. In the both groups, the serum TSH and anti-TPO antibody levels were measured and assessed before and after the intervention. Results: After the interventions, the mean serum TSH reduction in the intervention and placebo groups was −10.98 ± 33.31 and −3.20 ± 38.36, respectively, which were not statistically significant. However, the mean serum anti-TPO Ab concentration increased in the intervention and placebo groups (109.81 ± 51.49% vs. 173.17 ± 96.26%), between which the difference was not statistically significant (P >0.05) despite a slight increase in the mean anti-TPO level in the intervention group. Conclusion: The results of the current study indicated that selenium supplementation has no significant effect on serum anti-TPO Ab and TSH levels in the patients with subclinical hypothyroidism. Studies with larger sample size and with different doses of selenium are needed to reach more precise results.