Selenium supplementation for Hashimoto's thyroiditis.
Level 1 - systematic review of randomized trials
Systematic review of randomized controlled trials
PubMed 23744563 · doi:10.1002/14651858.CD010223.pub2
What was done
A Cochrane systematic review searched CENTRAL, MEDLINE, EMBASE, Web of Science, and clinical trial registries up to late 2012 for randomized controlled trials evaluating selenium supplementation in adults with Hashimoto's thyroiditis. Two authors independently performed study selection, risk of bias assessment, and GRADE evaluation. Due to substantial clinical heterogeneity across interventions, pooling data via meta-analysis was not possible.
What was found
Four RCTs comprising 463 participants (mean study duration 7.5 months, range 3–18 months) met inclusion criteria. None measured health-related quality of life, levothyroxine (LT4) dose changes, or economic costs. One small trial (n = 36) at high risk of bias found improved subjective well-being with sodium selenite 200 µg plus LT4 versus placebo plus LT4 (RR 4.67, 95% CI 1.61 to 13.50, p = 0.004). Selenomethionine 200 µg significantly reduced anti-thyroid peroxidase (anti-TPO) antibody levels versus placebo in two trials (MD -917 U/mL, 95% CI -1056 to -778, n = 85; and MD -345 IU/mL, 95% CI -359 to -331, n = 169), as well as when combined with LT4 (MD -1508 U/mL, n = 86; and MD -235 IU/mL, n = 88). In contrast, sodium selenite 200 µg did not significantly reduce anti-TPO antibodies (MD -25, 95% CI -181 to 131, n = 36). Adverse event rates did not significantly differ between selenium and placebo arms across two reporting studies.
Why it matters
While selenium can reduce surrogate biochemical markers (anti-TPO antibodies), there is insufficient evidence to show it improves clinical symptoms, quality of life, or LT4 replacement requirements in Hashimoto's thyroiditis.
Limits
All four included trials had unclear to high risk of bias, small sample sizes, and substantial clinical heterogeneity (I² = 99% for antibody reduction). Primary patient-centered outcomes (quality of life, thyroid hormone requirements, long-term safety) were not evaluated, making the clinical relevance of antibody reduction unclear.
Cited by
- contradicts Scientific research shows that selenium supplementation is beneficial for autoimmune conditions.