Selenium: What It Does and How Much You Need

An antioxidant that supports thyroid function and immunity. Brazil nuts are the richest source; good amounts are also found in fish, seafood, organ meats, and eggs.

Daily value

55 mcg

Why You Need It

Selenium is part of glutathione peroxidase and other enzymes that protect cells from oxidative damage. It's needed for converting thyroid hormones into their active form and for proper immune function.

Too Little or Too Much

Selenium content in plant foods varies a lot depending on the soil they grow in. Some regions have selenium-poor soil.

The gap between enough and too much is narrow: just 2–3 Brazil nuts cover your daily needs. Only take selenium supplements if your doctor recommends them.

Daily values are US Dietary Reference Intakes for adults 19–50. Nutrient content of foods varies with variety and cooking method. This is general information and does not replace advice from a doctor or dietitian.