What Food Has High Selenium?

Brazil nuts are the single most concentrated food source of selenium on the planet. Just one nut can provide more than the daily recommended amount for an adult. Other reliable sources include tuna, sardines, eggs, and sunflower seeds. This mineral is essential for thyroid function, reproduction, and protecting your body from oxidative damage.

What Is Selenium and Why Do You Need It?

Selenium is a trace mineral. Your body needs it in small amounts to function properly. It is a key part of selenoproteins, which are enzymes that help protect cells from damage.

Research shows selenium plays a critical role in thyroid hormone metabolism. The thyroid gland contains the highest concentration of selenium in the body. Without enough, your thyroid cannot produce or regulate hormones correctly. The National Institutes of Health states that selenium is also important for DNA synthesis and reproduction.

Most people in the United States get enough selenium from their diet. The recommended dietary allowance for adults is 55 micrograms per day. Pregnant and breastfeeding women need slightly more.

What Food Has High Selenium Content?

Brazil nuts are in a category of their own. One ounce, about six to eight nuts, contains roughly 544 micrograms of selenium. That is nearly 10 times the daily recommendation. Eating just one Brazil nut per day is enough for most people.

Seafood is another strong source. Here is a comparison of selenium content in common foods:

Meat and poultry are also decent sources. Chicken, beef, and turkey all provide selenium. The exact amount depends on what the animal ate. Grains and vegetables vary widely because selenium content in soil is not consistent across regions.

Can You Get Too Much Selenium?

Yes. Selenium toxicity is real and dangerous. The tolerable upper intake level for adults is 400 micrograms per day. Going above that regularly can cause selenosis.

Symptoms of too much selenium include a garlic-like breath odor, metallic taste in the mouth, hair loss, brittle nails, and nausea. Severe cases can lead to nerve damage and respiratory distress.

Brazil nuts are the most common cause of selenium overdose. Eating several nuts daily for weeks can push you past safe limits. The same applies to taking selenium supplements without knowing your dietary intake.

Most people do not need a supplement. A single Brazil nut or a serving of tuna covers your daily needs. If you eat a balanced diet, you likely get enough selenium already. The CDC reports that selenium toxicity is rare in the United States but does occur, mostly from over-supplementation or compulsive eating of Brazil nuts.

Does the Selenium Content in Food Vary by Region?

Yes, significantly. The selenium content of plant foods depends entirely on the soil where they were grown. In the United States, the Great Plains region has selenium-rich soil. Crops grown there, like wheat and corn, contain more selenium than those grown in other areas.

Parts of China, New Zealand, and Europe have low selenium soil. People in those regions may get less selenium from local produce. This is why some countries add selenium to fertilizers or animal feed.

Animal products also vary. Meat and eggs reflect the selenium content of the animal’s diet. A chicken that ate selenium-fortified feed will produce eggs with more selenium than one that did not. This is a reliable way to ensure adequate intake in low-selenium regions.

Brazil nuts are the exception. They are harvested from trees that grow in the Amazon basin, where the soil is naturally rich in selenium. This is why their content is so consistently high.

What Are the Best Food Sources for Vegetarians and Vegans?

Vegetarians and vegans need to be more intentional about selenium. Meat and seafood are the most concentrated sources, but plant-based options exist.

Here are the top selenium-rich foods for plant-based diets:

• Brazil nuts — one nut per day is enough
• Sunflower seeds — one ounce provides 18 mcg
• Brown rice — one cup cooked provides 19 mcg
• Chia seeds — one ounce provides about 15 mcg
• Mushrooms — especially shiitake, which provide about 5 mcg per cup

Grains like oats, barley, and whole wheat bread also contribute. The amount depends on the soil where the grain was grown. If you live in a region with low-selenium soil, you may need to rely more on Brazil nuts or seeds.

Some studies suggest that vegans have lower selenium levels than meat-eaters. A 2020 review in the journal Nutrients found that vegans in Europe were at risk of deficiency. If you follow a strict plant-based diet, consider checking your selenium intake every few months.

Common Misconceptions About Selenium in Food

A common myth is that all nuts are high in selenium. This is not true. Almonds, walnuts, and cashews contain very little selenium. Only Brazil nuts are exceptionally high. Eating a handful of mixed nuts will not give you the same selenium boost.

Another misconception is that selenium supplements are harmless because they are natural. This is false. Selenium supplements can cause toxicity quickly, especially if you also eat Brazil nuts or seafood. The form of selenium in supplements, selenomethionine, is absorbed very efficiently by the body. This makes overdose easier than with food sources.

Some people believe that cooking destroys selenium. It does not. Selenium is heat-stable. Boiling, baking, or frying does not reduce its content significantly. However, selenium can leach into cooking water. If you boil selenium-rich foods and discard the water, you lose some. Steaming or roasting is better.

Finally, there is a viral idea that eating more selenium prevents cancer. Large clinical trials have not confirmed this. The Selenium and Vitamin E Cancer Prevention Trial (SELECT) found no benefit from selenium supplements for prostate cancer prevention. Getting selenium from food is fine, but megadosing for cancer prevention is not supported by evidence.