Management of Hashimoto's Thyroiditis

Introduction to Supplements

Omega-3 fatty acids may help reduce inflammation in autoimmune conditions, with a typical dosage of 1g daily of EPA/DHA in a ratio of approximately 1:1.2, which has shown benefits in cardiovascular health that may benefit overall wellbeing, as suggested by the American Heart Association 1
Zinc supplementation at 15mg daily in a complete multivitamin and mineral supplement is important for thyroid function and immune regulation, and may be particularly helpful in cases with documented zinc deficiency, according to the Obesity Reviews guideline 2
Thiamine (B1) at 200-300mg daily may be beneficial for those with symptoms like fatigue, as recommended by the Obesity Reviews guideline 2

Selenium supplementation at a dose of 200 μg daily may reduce thyroid peroxidase antibody (TPOAb) levels and improve inflammatory symptoms in patients with mild Hashimoto's thyroiditis, particularly in those with selenium deficiency, as supported by the Clinical Nutrition journal 3, 4, 5
Water-soluble forms of fat-soluble vitamins may improve absorption, as recommended by the Obesity Reviews guideline 2
The standard dose used in most studies is 200 μg daily, with supplementation duration typically ranging from 3-6 months, and monitoring of response after 3-6 months by measuring TPOAb and TGAb levels, thyroid function tests, and subjective well-being/quality of life 5

The Obesity Reviews guideline suggests considering a comprehensive multivitamin containing zinc, selenium, and other trace minerals, and testing for deficiencies before supplementation when possible 2
Supplement quality matters, and pharmaceutical-grade products should be chosen when possible, with monitoring of thyroid function and antibody levels every 3-6 months to assess effectiveness, as suggested by the American Heart Association 1
Assess selenium status if possible, as supplementation appears most beneficial in those with deficiency, and excessive selenium intake can lead to toxicity (selenosis), though this is uncommon at therapeutic doses 5
The overall evidence quality remains moderate, with most studies having unclear to high risk of bias, and clinical relevance of antibody reduction remains uncertain in some studies, as reported in the Clinical Nutrition journal 5

Most beneficial effects of selenium supplementation are observed in patients with mild Hashimoto's thyroiditis, and in those with confirmed selenium deficiency, with response varying based on baseline selenium status of the population 4, 5
Effects observed in selenium-deficient populations may not translate to selenium-sufficient populations, highlighting the importance of assessing selenium status before supplementation 4, 5

Adverse events appear rare in studies of selenium supplementation, but monitoring of thyroid function and antibody levels is recommended every 3-6 months to assess effectiveness and potential toxicity 5
A Danish RCT showed that selenium supplementation (100-300 μg/day) decreased TSH and FT4 concentrations in euthyroid subjects with marginal selenium deficiency, demonstrating the potential benefits and risks of supplementation 5