Last Updated on April 26, 2026
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All content on ThyForLife is developed from peer-reviewed scientific literature, published clinical guidelines, and data from accredited medical research institutions.
Why Selenium matters for your thyroid
Selenium is a trace mineral your thyroid cannot function without. The thyroid gland contains the highest concentration of selenium per gram of tissue of any organ in the body — it relies on selenium-dependent enzymes called deiodinases to convert the inactive thyroid hormone T4 into the active form T3 that your cells can use. Selenium also powers glutathione peroxidase enzymes that protect the thyroid from the oxidative stress generated during hormone production.
Research published in Thyroid (2015) found that in selenium-deficient regions, rates of autoimmune thyroid disease — including Hashimoto’s thyroiditis — are significantly higher. Getting enough selenium from food is a practical first line of defense.
Let’s find out the top 10 foods high in selenium according to the National Institutes of Health.
How much selenium do you need?
The National Institutes of Health (NIH) recommends:
- Adults (19+): 55 mcg/day
- Pregnant women: 60 mcg/day
- Breastfeeding women: 70 mcg/day
- Children 1–3 years: 20 mcg/day
The upper tolerable intake level (UL) is 400 mcg/day for adults — exceeding this over time can cause selenosis (selenium toxicity). Most people can meet their daily needs through food alone, though those with certain thyroid conditions may benefit from supplementation under medical supervision.
Selenium content in common foods: Quick reference table
The table below shows the selenium content of common foods. Values are sourced from the USDA FoodData Central database and the NIH Office of Dietary Supplements.
Top 10 foods high in selenium
As described in our previous article, selenium plays an important role in thyroid health. Let’s find out the top 10 foods high in selenium according to the National Institutes of Health.
1. Brazil nuts
Brazil nuts are one of the best foods high in selenium. One serving, or about six to eight nuts, contains about 544 mcg of this micronutrient. Besides, Brazil nuts are a great option for vegans and vegetarians.
Important caveat: Because Brazil nuts are so concentrated in selenium, eating more than 1–2 servings per day could push you over the 400 mcg/day upper limit. A case report in the New England Journal of Medicine documented selenosis symptoms in a woman who ate large quantities daily. Stick to a small handful (4–6 nuts) a few times per week rather than eating them every day.
Selenium Content in Foods: Quick Reference
| Food | Serving | Selenium (mcg) | % Daily Value |
|---|---|---|---|
| Brazil nuts | 1 oz (6–8 nuts) | 544 | 989% |
| Yellowfin tuna | 3 oz | 92 | 167% |
| Halibut | 3 oz | 47 | 85% |
| Sardines (canned) | 3 oz | 45 | 82% |
| Shrimp | 3 oz | 40 | 73% |
| Beef steak | 3 oz | 33 | 60% |
| Turkey | 3 oz | 31 | 56% |
| Tofu | 1 cup | 43.8 | 80% |
| Enriched pasta | 1 cup | 37 | 67% |
| Eggs | 1 large | 15 | 27% |
| Cottage cheese | 1 cup | 20 | 36% |
| Brown rice | 1 cup | 19 | 35% |
| Baked beans | 1 cup | 13 | 24% |
| Sunflower seeds | 1 oz | 11.9 | 22% |
| Spinach (cooked) | 1 cup | 3.5 | 6% |
*Daily Value: 55 mcg/day for adults. Source: USDA FoodData Central & NIH Office of Dietary Supplements.
2. Other nuts and seeds
Even though Brazil nuts contain the highest amount of selenium, most of the other nuts and seeds have decent quantities of it. For instance, one ounce of sunflower seeds contains 11.9 mcg of selenium.
Sunflower seeds, sesame seeds, and cashews are good plant-based selenium sources — especially useful for vegetarians and vegans who may have lower overall selenium intake. Note that the selenium content of plant foods varies significantly depending on the selenium content of the soil where they were grown.
Selenium-rich foods your thyroid needs
Log selenium-rich foods alongside your thyroid levels to optimize your diet. Plus self-care tools for sleep, mental health, and physical wellness designed specifically for people with thyroid conditions. Free on iOS and Android.
Download ThyForLife for Free3. Tuna
3 ounces of yellowfin tuna contain about 25 grams of protein and 92 mcg of selenium, making it an excellent product for a healthy lifestyle.
Tuna provides selenium in the highly bioavailable organic form selenomethionine. A 2015 review in Nutrients found that selenium from fish and seafood is absorbed at a rate of 85–90%, significantly higher than from inorganic supplement sources. Canned light tuna is also lower in mercury than albacore, making it a safer frequent choice.
4. Beef steak
Great news for the meat lovers – steak is not just delicious – it is also beneficial for your thyroid health. The bottom round beef steak will provide you with about 33 mcg of selenium per 3 ounces of meat, which covers nearly 60% of your daily need!
Grass-fed beef may contain more selenium than grain-fed, depending on the selenium content of the pasture soil. Lean cuts are preferable — the selenium is in muscle tissue, not fat.
5. Turkey
You can get 31 mcg of selenium from 3 oz of roasted turkey. Sounds like a legit reason to cook it not only on Thanksgiving!
Turkey also provides zinc and iron — two other minerals important for thyroid function. For Hashimoto’s patients watching their diet, lean turkey is a low-inflammatory protein source that pairs well with thyroid-supporting nutrition patterns.
6. Baked beans
Baked beans are an amazing low-budget source of selenium – just one cup brings about 13 mcg of selenium, which covers almost 25% of your daily need.
Legumes are a practical plant-based source, though their selenium content varies based on growing conditions. Baked beans also provide fiber that supports gut health — emerging research on the gut-thyroid axis suggests that gut microbiome diversity may influence thyroid antibody levels.
7. Tofu
Tofu is another affordable product you should introduce into your diet! One cup of plain tofu covers 80% of daily selenium need (43.8 mcg).
Note for those with Hashimoto’s: there is ongoing discussion about soy’s effect on thyroid function. Current evidence suggests that soy does not harm thyroid function in people with adequate iodine intake, but it may interfere with levothyroxine absorption if consumed within 4 hours of your medication. Speak with your doctor about timing.
8. Eggs
One egg provides about 15 mcg of selenium. Thus, a two egg omelet will cover almost 60% of your daily selenium need.
Selenium is concentrated in the egg white (albumin). Eggs are also one of the few foods that naturally contain vitamin D, another nutrient closely tied to thyroid autoimmunity. A 2018 meta-analysis in Nutrients found lower vitamin D levels in patients with Hashimoto’s thyroiditis compared to healthy controls.
9. Cottage cheese
Another reason to visit your local farmer – one cup of cottage cheese provides about 20 mcg of selenium!
Dairy products are a reliable selenium source in countries where animal feed is selenium-enriched (such as Finland and the US). Low-fat cottage cheese is also a high-protein, low-calorie option that fits well into thyroid-supportive eating patterns.
10. Enriched pasta
Enriched products are those that lost nutrients during processing and, in order to compensate it, vitamins and minerals are added back at the end of the production. A cup of such macaroni contains about 37 mcg of selenium, thus covering 67% of daily need in it.
Cooked enriched pasta provides approximately 37 mcg selenium per cup (about 67% of the daily value). Whole grain pasta contains less selenium than enriched pasta because the selenium is added back during the enrichment process. If you’re gluten-free due to thyroid-related conditions (celiac disease co-occurs with Hashimoto’s in up to 6% of cases per a 2018 study in Frontiers in Endocrinology), rice-based alternatives can still provide selenium through other foods in your diet.
Bioavailability: Not all selenium is absorbed equally
The form of selenium determines how well your body absorbs and uses it:
- Organic selenium (selenomethionine, from animal proteins and some plants): absorbed at ~85–90%
- Inorganic selenium (selenite, from drinking water and soil): absorbed at ~50–70%
- Selenocysteine (from fish and meat): highly bioavailable and directly incorporated into selenoproteins
A 2003 review in the American Journal of Clinical Nutrition confirmed that selenomethionine from food is the most efficiently absorbed form — one reason food sources are preferred over inorganic supplements when diet alone can meet requirements.
Why selenium content in food varies
A key factor many people overlook: the selenium content of plant foods depends almost entirely on the selenium content of the soil where they were grown. This varies enormously by geography:
- Parts of the United States (Great Plains) have selenium-rich soils; Pacific Northwest and East Coast soils tend to be lower
- Large areas of Europe, China, and New Zealand have selenium-poor soils
- A 2011 study in the British Journal of Nutrition found that selenium intake in the UK has declined significantly since the shift away from selenium-rich North American wheat
Animal foods (meat, fish, eggs) are more reliable sources because selenium concentrates up the food chain regardless of soil levels in the animal’s feed.
Signs you may not be getting enough selenium
Selenium deficiency is uncommon in the US but can occur, especially in people with inflammatory bowel disease, those who have had gastrointestinal surgery, or those who eat a limited diet. Warning signs include:
- Fatigue and muscle weakness
- Hair thinning or loss
- Weakened immune response (frequent infections)
- Thyroid dysfunction — particularly impaired T4-to-T3 conversion
- Mood changes (selenium plays a role in serotonin metabolism)
If you suspect deficiency, your doctor can order a serum selenium test. Normal range is 70–150 ng/mL. Because serum selenium reflects recent intake, a whole blood selenium test may better reflect long-term status.
Cooking tips to preserve selenium
Selenium is relatively stable during cooking compared to some vitamins, but high-heat and prolonged cooking can cause minor losses:
- Steaming or baking preserves more selenium than boiling (water leaches some selenium-containing amino acids)
- Avoid overcooking fish — selenium losses increase with prolonged high-heat cooking
- Soaking and draining legumes reduces their selenium content slightly — add variety to compensate
When food alone may not be enough
For most healthy people, a varied diet provides adequate selenium. However, thyroid patients — particularly those with Hashimoto’s thyroiditis — may benefit from selenium supplementation in addition to food sources, based on clinical trial evidence. Multiple randomised controlled trials have shown that 200 mcg/day of selenomethionine reduces thyroid peroxidase (TPO) antibodies significantly in Hashimoto’s patients.
If you’re eating selenium-rich foods regularly but still have high TPO antibodies or persistent thyroid symptoms, speak with your endocrinologist about whether a selenium supplement makes sense for your individual situation. Always test before supplementing — serum selenium testing helps ensure you’re not already at the upper end of the range.
Further Reading on Selenium
Now that you know which foods are highest in selenium, explore how it affects your thyroid and what to look for in a supplement:
- Selenium for Thyroid Health: Why It Matters — the science behind selenium’s role in Hashimoto’s, Graves’ disease, and pregnancy
- How to Choose the Best Selenium Supplement — which form is most bioavailable, dosage guidance, and safety
