In brief
A mineral your thyroid gland needs to make hormones. Selenium is also needed for reproduction, to make DNA, to help protect cells and to resist infection.
- Women with low selenium have a higher risk of thyroid disease, but a few studies found that selenium supplements do not provide much benefit for the thyroid.
- People on kidney dialysis and people living with HIV are more likely to have low selenium.
- Diets made up mostly of plant foods grown in low-selenium soils can be low in selenium.
How it works
Brazil nuts contain very high amounts, about 68 to 91 micrograms per nut. Fish and other seafood, meat, poultry, eggs and dairy foods are other sources.
Too much selenium over time can cause garlic breath, a metallic taste, hair loss and nervous system problems, and very high amounts can cause severe stomach and nerve problems.
Food sources
- Brazil nuts in small amounts
- Seafood
- Meat and poultry
- Eggs
- Dairy foods
From the AskBioMap food guide:
Connections
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Selenium is needed for
Your thyroid gland needs selenium to produce hormones.
Source: NIH Office of Dietary Supplements, Selenium fact sheet for consumers
Selenium has been studied for
- Hashimoto's disease Emerging
A few studies found selenium supplements do not provide much benefit for the thyroid.
Source: NIH Office of Dietary Supplements, Selenium fact sheet for consumers
Sources
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Summarised from the NIH Office of Dietary Supplements. Sources read on 13 October 2026. General education only, not medical advice. Spotted a mistake? Please tell us through the HuBu-Intel contact page.