Taking 200 micrograms of selenium daily for three months may lower levels of thyroid peroxidase antibodies in people with autoimmune thyroiditis who have normal thyroid function, indicating a possible effect on the autoimmune process.
Evidence from Studies
No evidence studies found yet.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
Whether selenium supplementation consistently reduces TPOAb titers across diverse populations of euthyroid autoimmune thyroiditis patients, accounting for baseline selenium status, genetic factors, and long-term outcomes.
A systematic review and meta-analysis of all randomized controlled trials evaluating 200 μg/day selenium (as selenomethionine or sodium selenite) for at least 3 months in adults aged 18–70 with confirmed euthyroid autoimmune thyroiditis (TPOAb > 35 IU/mL), measuring TPOAb and TgAb changes as primary outcomes, with subgroup analyses by baseline selenium levels, TPOAb titers, and presence of thyroid ultrasound abnormalities.
Whether selenium supplementation causes a sustained reduction in TPOAb titers and whether this effect is clinically meaningful in terms of preventing progression to hypothyroidism.
A double-blind, placebo-controlled RCT with 300+ euthyroid adults (aged 25–65) with confirmed autoimmune thyroiditis (TPOAb > 100 IU/mL), randomized to 200 μg/day selenium (selenomethionine) or placebo for 12 months, with primary outcome being TPOAb reduction ≥30% at 12 months and secondary outcomes including TSH normalization, thyroid volume change on ultrasound, and incidence of overt hypothyroidism.
Whether individuals with autoimmune thyroiditis who take selenium supplements over time have a lower rate of progression to hypothyroidism compared to those who do not.
A prospective cohort study following 500 euthyroid adults with autoimmune thyroiditis (TPOAb > 50 IU/mL) for 5 years, stratifying by selenium supplement use (yes/no), with annual measurements of TSH, TPOAb, TgAb, and thyroid ultrasound, controlling for iodine intake, smoking, and vitamin D status.
Whether selenium supplementation is less common among individuals who progress from euthyroid to overt hypothyroidism within 2 years compared to those who remain euthyroid.
A case-control study comparing 100 euthyroid autoimmune thyroiditis patients who developed overt hypothyroidism (TSH > 10 mIU/L) within 2 years to 100 matched controls who remained euthyroid, retrospectively assessing selenium supplement use, baseline selenium levels, and dietary intake.
Whether serum selenium levels correlate with TPOAb titers at a single point in time in euthyroid autoimmune thyroiditis patients.
A cross-sectional analysis of 1000 euthyroid adults with autoimmune thyroiditis, measuring serum selenium concentration and TPOAb titer simultaneously, adjusting for age, sex, BMI, iodine intake, and geographic selenium status.