15 Selenium-Rich Foods for Thyroid and Immunity
Selenium powers your thyroid and your strongest antioxidant defense system. These foods have the most — and one of them needs only two pieces a day.
Data-backed ranking of the strongest food sources
Daily value context so the numbers mean something
Usage tips and tradeoffs, not just a list of names
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EatAndAchieve Editorial System
AI-assisted editorial system
This content is assembled from USDA FoodData Central data, in-house ranking logic, and reusable editorial templates to make nutrition information easier to understand.
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Jordan Vale
Founder, editor, and product builder
Jordan reviews pages for clarity, methodology, and product accuracy before they go live. He also maintains the code, data pipeline, and editorial standards for the site.
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Pages on EatAndAchieve combine USDA source data, site-specific scoring logic, and AI-assisted drafting, then receive human review for clarity and methodology. They are educational tools, not medical advice. Read more on the About page.
This ranking focuses on foods that meaningfully deliver selenium per 100g, using USDA FoodData Central as the source of truth. It is a concentration ranking, not a full health score, so the most useful way to read it is to look for foods that fit both your nutrient target and your normal portion sizes.
Why it matters
Selenium is a trace mineral essential for thyroid function, DNA synthesis, and protection from oxidative damage. It is a component of selenoproteins including glutathione peroxidases — your body's most important antioxidant enzyme family. Selenium also plays a role in immune function and may reduce cancer risk.
Daily target
The FDA daily value is 55mcg. The margin between adequate and toxic is narrower for selenium than for most nutrients — the upper limit is 400mcg. Brazil nuts are so rich in selenium that eating more than 2-3 per day can push you toward the upper limit.
How to use the list
Just 1-2 Brazil nuts per day covers your selenium needs. Seafood, organ meats, and eggs are also reliable sources. Selenium content in plant foods varies dramatically based on soil selenium levels, which differ by geographic region.
Screening rule
Foods had to clear basic practicality filters before ranking so the list stays useful, not just technically correct.
Best use case
Use this template when you want the single strongest sources of one nutrient and you are willing to compare foods mainly on that axis.
Main caveat
Per-100g leaders are not always everyday staples, which is why calorie density and tradeoffs are called out inside the list.
Nuts, brazilnuts, dried, unblanched sits at the top because 1920mcg of selenium per 100g is hard for anything else to match. 3491% of the daily value is enough to make this a serious contributor rather than a token source. At 659 kcal per 100g, the nutrient density is strong but the portion size still deserves respect. There is more here than the main number alone, especially the protein (29% DV) and fiber (27% DV).
Worth knowing
High in saturated fat with 16.1g per 100g, which is worth watching if you are managing heart health or cholesterol.
Mollusks, oyster, Pacific, cooked, moist heat belongs in the top tier of this ranking, with 154mcg of selenium per 100g. You are looking at 280% of the daily value per 100g, which is why it stands out in a nutrient-specific ranking like this. It also brings useful amounts of protein (38% DV) and iron (51% DV), so it is not just a one-stat food.
Worth knowing
Relatively high in cholesterol at 100mg per 100g.
Turkey, young hen, skin only, cooked, roasted ranks this highly because it is one of the cleaner ways to get a lot of selenium quickly. 262% of the daily value is enough to make this a serious contributor rather than a token source. At 482 kcal per 100g, the nutrient density is strong but the portion size still deserves respect. A secondary plus is its protein (38% DV).
Worth knowing
High in saturated fat with 11.6g per 100g, which is worth watching if you are managing heart health or cholesterol.
Fish, tuna, yellowfin, fresh, cooked, dry heat belongs in the top tier of this ranking, with 108mcg of selenium per 100g. That translates to 196% of the daily value, so it can materially move your intake in one serving. A secondary plus is its protein (58% DV). Because protein is high too, it is easier to build a full meal around than some single-purpose nutrient sources.
Seeds, sunflower seed butter, without salt makes the cut on substance, not hype: 104mcg per 100g is enough to matter in an actual diet. 189% of the daily value is enough to make this a serious contributor rather than a token source. At 617 kcal per 100g, the nutrient density is strong but the portion size still deserves respect. It also brings useful amounts of protein (35% DV) and fiber (20% DV), so it is not just a one-stat food.
Worth knowing
High in saturated fat with 4.68g per 100g, which is worth watching if you are managing heart health or cholesterol.
Turkey, all classes, liver, cooked, simmered holds its spot because 102mcg of selenium is still comfortably strong. You are looking at 185% of the daily value per 100g, which is why it stands out in a nutrient-specific ranking like this. The extra protein (54% DV) and vitamin C (25% DV) help this entry hold up outside of the headline nutrient. Because protein is high too, it is easier to build a full meal around than some single-purpose nutrient sources.
Worth knowing
Relatively high in cholesterol at 648mg per 100g.
Mollusks, mussel, blue, cooked, moist heat makes the cut on substance, not hype: 90mcg per 100g is enough to matter in an actual diet. You are looking at 163% of the daily value per 100g, which is why it stands out in a nutrient-specific ranking like this. The extra protein (48% DV) and iron (37% DV) help this entry hold up outside of the headline nutrient.
Mollusks, octopus, common, cooked, moist heat makes the cut on substance, not hype: 90mcg per 100g is enough to matter in an actual diet. 163% of the daily value is enough to make this a serious contributor rather than a token source. The extra protein (60% DV) and iron (53% DV) help this entry hold up outside of the headline nutrient. The strong protein content makes it more practical than foods that only win on one micronutrient.
Worth knowing
High in sodium at 460mg per 100g, so it may not be the best fit for a low-sodium diet.
Semolina, enriched is not the flashiest name on the page, but the nutrient density is real at 89mcg per 100g. 163% of the daily value is enough to make this a serious contributor rather than a token source. At 360 kcal per 100g, the nutrient density is strong but the portion size still deserves respect. It also brings useful amounts of protein (25% DV) and iron (24% DV), so it is not just a one-stat food.
Wheat, durum lands lower on the page, but 89mcg per 100g is still better than what you get from most foods. That translates to 163% of the daily value, so it can materially move your intake in one serving. There is more here than the main number alone, especially the protein (27% DV) and iron (20% DV).
Fish, roughy, orange, cooked, dry heat lands lower on the page, but 88mcg per 100g is still better than what you get from most foods. 161% of the daily value is enough to make this a serious contributor rather than a token source. A secondary plus is its protein (45% DV).
Worth knowing
Relatively high in cholesterol at 80mg per 100g.
Wheat, khorasan, uncooked lands lower on the page, but 82mcg per 100g is still better than what you get from most foods. 148% of the daily value is enough to make this a serious contributor rather than a token source. It also brings useful amounts of protein (29% DV) and fiber (40% DV), so it is not just a one-stat food. High fiber helps this food feel more useful in real meals, not just in spreadsheets.
Noodles, egg, dry, enriched lands lower on the page, but 79mcg per 100g is still better than what you get from most foods. 143% of the daily value is enough to make this a serious contributor rather than a token source. At 384 kcal per 100g, the nutrient density is strong but the portion size still deserves respect. The extra protein (28% DV) and iron (22% DV) help this entry hold up outside of the headline nutrient.
Worth knowing
Relatively high in cholesterol at 84mg per 100g.
Fish, mackerel, salted rounds out the ranking with 73mcg per 100g, which is still enough to be useful if it already fits your meals. 133% of the daily value is enough to make this a serious contributor rather than a token source. A secondary plus is its protein (37% DV).
Worth knowing
High in sodium at 4450mg per 100g, so it may not be the best fit for a low-sodium diet.
Crustaceans, lobster, northern, cooked, moist heat is here because even the back half of this list still offers respectable selenium density. 133% of the daily value is enough to make this a serious contributor rather than a token source. The extra protein (38% DV) and zinc (37% DV) help this entry hold up outside of the headline nutrient.
Worth knowing
High in sodium at 486mg per 100g, so it may not be the best fit for a low-sodium diet.