Nutrition Diet Guide: Which food is best for selenium?

October 7, 2025 •

3 min read

According to the National Institutes of Health, selenium is a trace mineral vital for thyroid function, DNA synthesis, and protection from oxidative damage. When considering which food is best for selenium, the answer is definitively Brazil nuts, which contain exceptionally high levels of this essential nutrient. However, a variety of other foods can also help you meet your daily needs without risk of overconsumption.

Quick Summary

This article details the highest selenium foods, with Brazil nuts leading the list, and explains how to integrate various other sources into a balanced diet. It outlines the health benefits of maintaining optimal selenium levels, discusses the risks of both deficiency and toxicity, and provides practical dietary advice for sourcing this crucial mineral.

Key Points

Brazil Nuts are the richest source: Just one to two Brazil nuts consumed a few times a week can easily meet or exceed the recommended daily allowance for selenium.
Seafood is a top-tier source: Many types of fish and shellfish, like tuna, sardines, and oysters, offer high and reliable amounts of selenium.
Animal products provide consistent selenium: Meat, poultry, and eggs contain significant levels of selenium that are less impacted by environmental factors than plant sources.
Plant-based sources are variable: The selenium content in grains, seeds, and vegetables depends on the soil, so consuming a variety is important.
Moderation prevents toxicity: Excessive intake, particularly from too many Brazil nuts or supplements, can lead to selenosis, so it's vital not to exceed safe limits.
Balance is better than focusing on one food: A diverse diet incorporating various selenium-rich foods ensures adequate intake while minimizing risk.
Deficiency has distinct signs: Symptoms like fatigue, hair loss, and weakened immunity may indicate a selenium deficiency and warrant attention.

What Is Selenium and Why Do We Need It?

Selenium is a trace mineral that our bodies require in small amounts for many critical functions, yet it cannot be produced naturally. We must obtain it through our diet. It's a key component of selenoproteins, which are enzymes that play essential roles in:

Antioxidant defense: Selenium helps create powerful antioxidant enzymes that protect cells from damage caused by free radicals, which are linked to aging and chronic diseases like heart disease and cancer.
Thyroid health: The thyroid gland contains a high concentration of selenium, which is crucial for the production and metabolism of thyroid hormones.
Immune system function: Adequate selenium levels are necessary for a robust immune response, helping the body fight off infections from viruses and bacteria.
Reproductive health: It is important for both male and female fertility.

The Ultimate Source: Which food is best for selenium?

Without a doubt, Brazil nuts are the single most concentrated dietary source of selenium. A single nut can often provide the entire recommended daily allowance (RDA) for an adult. For context, one ounce (about 6-8 nuts) can contain as much as 544 mcg of selenium, which is almost 10 times the RDA of 55 mcg.

Caution on Brazil nuts

While incredibly potent, this high concentration means moderation is crucial. Eating too many too frequently can lead to selenium toxicity (selenosis), with an upper tolerable intake level of 400 mcg per day for adults. A practical recommendation is to limit intake to just one or two Brazil nuts a few times a week to safely reap their benefits without risk of overconsumption.

Excellent Animal-Based Selenium Sources

Animal-based foods are considered reliable sources of selenium because the levels are less dependent on varying soil conditions.

Seafood

Seafood is an excellent source of selenium, particularly fish and shellfish. Choices include yellowfin tuna, sardines, oysters, shrimp, halibut, and salmon.

Meat and Poultry

Lean meats and poultry also contribute significantly. Options include pork, beef (like bottom round steak and liver), turkey, and chicken breast.

Eggs and Dairy

Common foods like eggs and cottage cheese offer a simple way to increase selenium intake.

Plant-Based Options for Selenium Intake

The selenium content in plant foods varies based on soil quality. Plant-based sources include grains like brown rice and whole-wheat pasta, legumes such as lentils and baked beans, seeds and nuts including sunflower seeds and pistachios, and vegetables like mushrooms, spinach, and cabbage.

Comparison Table: Selenium Content in Common Foods


Food (per serving)	Serving Size	Approximate Selenium (mcg)	% Daily Value (55 mcg)	Notes
Brazil Nuts	1 nut	68-91	124-165%	Content highly variable; eat in moderation
Yellowfin Tuna	3 oz cooked	92	167%	Excellent source
Sardines (canned)	3 oz	45	82%	Good source of Omega-3s
Shrimp	3 oz cooked	42	76%	Versatile seafood option
Pork Chop	3 oz cooked	37	67%	Lean meat choice
Beef Steak	3 oz cooked	33-37	60-67%	Content can vary by cut
Chicken Breast	3 oz roasted	22	40%	Reliable, lean source
Cottage Cheese	1 cup, 1% milkfat	20	36%	Great for breakfast
Large Egg	1 hard-boiled	15	27%	Easy and versatile
Brown Rice	1 cup cooked	12	22%	Whole-grain option

Potential Symptoms of Selenium Deficiency

A selenium deficiency can lead to fatigue, muscle weakness, a weakened immune system, hair loss, nail discoloration, brain fog, thyroid issues, and infertility.

Symptoms of Selenium Toxicity (Selenosis)

Consuming too much selenium can result in symptoms such as garlic breath, a metallic taste in the mouth, hair loss, brittle nails, gastrointestinal issues, and in severe cases, neurological problems.

Conclusion: Achieving a Balanced Selenium Diet

While Brazil nuts are an exceptional source of selenium, a balanced approach involving a variety of foods is the best way to meet your needs and avoid toxicity. Including a mix of seafood, lean meats, poultry, eggs, whole grains, and a small number of Brazil nuts in your diet supports optimal selenium intake and overall health.

For more detailed information on dietary reference intakes and the health effects of selenium, consider consulting authoritative sources like the National Institutes of Health. NIH Office of Dietary Supplements fact sheet on Selenium

Frequently Asked Questions

Brazil nuts are the food with the highest selenium content. Just one or two nuts can provide more than the recommended daily amount, though moderation is key to avoid consuming too much.

Yes, it is possible to get enough selenium from a plant-based diet by consuming a variety of selenium-rich foods. However, because content in plants depends on soil quality, focusing on a diverse diet that includes sources like brown rice, sunflower seeds, and legumes is crucial.

Common symptoms of a selenium deficiency include fatigue, hair loss, a weakened immune system, muscle weakness, and issues with thyroid function.

Due to their extremely high and variable selenium content, it is generally recommended to eat only one to three Brazil nuts a few times per week. This prevents the risk of reaching toxic levels, which can occur from overconsumption.

For most people with a balanced diet, obtaining selenium from food is sufficient and safer. Supplements are typically only recommended for those with a diagnosed deficiency, as high doses from supplements can increase toxicity risk.

Selenosis is selenium toxicity caused by excessive intake. It can be avoided by staying within the tolerable upper intake level of 400 mcg per day and consuming selenium primarily through a varied diet rather than large quantities of supplements or Brazil nuts.

The recommended daily amount of selenium for adults (ages 14 and up) is 55 micrograms (mcg). This amount is slightly higher for pregnant women (60 mcg) and lactating women (70 mcg).