🔬 The science, kept simple
Selenium powers a family of antioxidant enzymes that protect cells from oxidative damage and help convert thyroid hormone into its active form. The amounts involved are tiny, and one food is so rich in it that supplementation is rarely the answer.
Why you need it: Antioxidant defense, thyroid function, and healthy immune response.
Daily target: About 55 micrograms a day.
🥇 Best food sources, ranked
- Brazil nuts ... about 90 mcg in a single nut
- Whole grains ... about 10-20 mcg per serving, soil-dependent
- Sunflower seeds ... about 15 mcg per ounce
- Mushrooms ... about 8 mcg per half cup
- Lentils ... about 6 mcg per cup
Figures are approximate, in the style of USDA FoodData Central; real foods vary with soil, variety, and cooking.
⚖️ Worth knowing
The gap between enough and too much is narrower than for most nutrients. One or two Brazil nuts a day is plenty... eating handfuls daily can actually overshoot.
Matters most for
Educational information, not medical advice. Talk with your doctor before supplements, especially with kidney, thyroid, or heart conditions or in pregnancy.