A perhaps neglected trace mineral, selenium must be obtained through diet and is absolutely vital to optimal thyroid and hormonal health.
Selenium serves a variety of essential roles within the body, including enzymatic functions that “catalyze thyroid hormone production.” This means they contribute to normal thyroid hormone production and also help to regulate the immune system – which relies on selenium. Selenium also serves as an antioxidant within the body to help protect against oxidative damage and stress. It helps the production of glutathione, deiodinase enzymes (thyroid and hormonal metabolites), and thioredoxin reductase (making DNA from RNA precursors). There is some general speculation that selenium can help in conditions of Hashimoto’s by lowering the amount of thyroid peroxidase antibodies.
In food, selenium is commonly derived from Brazil nuts, mushrooms, seeds, seafood & fish, and beef. While the forms of selenium found both in meat and in plant foods are highly bioavailable (90%), those who don’t eat meat or nuts (due to allergy, belief, or dietary restriction) may be lacking enough of this important mineral.
Selenium Supplementation – Why it Matters
Many of the benefits of selenium are believed to be due to ‘selenoproteins,’ which modulate the biological effects of selenium within the body.
As we cannot produce selenium ourselves internally, we need to rely on our diet to obtain enough for healthy physiological function.
Selenium was found to:
- Enhance the body’s immune response; both TH1 (viruses + intracellular bacteria) and TH2 (parasitic infections and extracellular parasites). A selenium deficiency has been demonstrated to slow immune cell response, with higher markers of inflammation, and reduced function of T-cells.
- Prevent oxidative damage from free radicals, as selenium functions as an antioxidant – this can prevent cellular damage from internal bodily processes (metabolizing food) and external toxins (cigarettes, pollution). Oxidative stress is a well-known marker of chronic disease and a contributor to cognitive disorders and cardiovascular disorders.
- A meta-analysis found that increased levels of selenium were associated with a reduced risk of heart disease, with selenium effectively reducing “C-reactive protein” (CRP), which is a prominent marker of inflammation. Conversely, selenium helped to raise the levels of the powerful antioxidant glutathione peroxidase.
- Selenium functions as a catalyst for proper thyroid hormone production. There is an evident link between thyroid metabolism and selenium deficiency. It helps protect the thyroid from oxidative damage, and from antibodies that contribute to or progress thyroid diseases like Hashimoto’s or Graves. Selenium supplementation appeared to drastically reduce the percentage of thyroiditis and hypothyroidism in clinical students, and decrease anti-thyroid antibody levels. The research regarding selenium for thyroid health is extremely promising.
Selenium Supplementation – Is it Safe?
When it comes to supplementation, they offer an effective way to either ensure enough dietary selenium intake or reverse a deficiency.
Generally, the recommended dietary allowance (RDA) is 55mcg daily, with the “tolerable upper intake” (I.E., the safest maximum dosage) at 400mcg daily. Most supplemental forms of selenium will be in the range of 50mcg – 200mcg, so taking one capsule daily can help you maintain intake without going overboard.
Selenium has a very low-risk factor when it comes to safety profile; most adverse impacts result from topical selenium sulfide – this is generally not the form you’ll find present in the supplements we carry. Ingesting internally, there are no severe adverse reactions reported.
However, those with a thyroid issue or hormonal issue may want to ensure they don’t exceed the RDA and talk to a health care professional like a naturopath prior to use. Selenium may also cause some slight gastrointestinal distress in users with IBD or IBS. Extremely high levels of selenium can cause fatigue, joint pain, nausea, and diarrhea. Ceasing the use of selenium supplements seems to prevent the progression of these symptoms.