The Effects of Selenium Supplementation in the Treatment of Autoimmune Thyroiditis: An Overview of Systematic Reviews.
Level 1 - systematic review of randomized trials
Overview of systematic reviews and meta-analysis of randomized controlled trials
PubMed 37513612 · doi:10.3390/nu15143194
What was done
Authors conducted an overview of systematic reviews and meta-analysis evaluating selenium supplementation in autoimmune thyroiditis (AIT). Databases (PubMed, Web of Science, Embase, Cochrane Library) were searched to June 10, 2022. Methodological quality was evaluated with AMSTAR-2, data from underlying randomized controlled trials were synthesized, and evidence certainty was graded using GRADE.
What was found
Six systematic reviews containing 75 RCTs were included; only one review was rated high quality. Meta-analysis showed: - In levothyroxine (LT4)-treated patients, selenium significantly lowered thyroid peroxidase antibodies (TPO-Ab) at 3 months (SMD = -0.53, 95% CI: [-0.89, -0.17], p < 0.05, very low certainty) and 6 months (SMD = -1.95, 95% CI: [-3.17, -0.74], p < 0.05, very low certainty), but not thyroglobulin antibodies (Tg-Ab). - In non-LT4-treated patients, TPO-Ab and Tg-Ab significantly decreased at 3 and 6 months but not at 12 months (no effect estimates reported in abstract). - Adverse effects did not differ significantly from control (low certainty).
Why it matters
This umbrella review clarifies that while selenium may transiently lower thyroid autoantibodies over 3 to 6 months, the effect is not sustained at 12 months and is supported only by low to very low certainty evidence.
Limits
Only 1 of 6 included reviews met high-quality standards on AMSTAR-2. All clinical outcomes had low or very low GRADE certainty, the abstract omits numerical values for non-LT4 subgroups, and no long-term clinical or symptom outcomes were reported.
Cited by
- partial Scientific research shows that selenium supplementation is beneficial for autoimmune conditions.