11 Selenium-Rich Foods That Support Thyroid Health and Boost Immunity

Selenium is a vital trace mineral that plays a crucial role in maintaining overall health. It supports thyroid function, boosts immunity, and protects the body from oxidative stress and chronic diseases. Despite being an essential nutrient, selenium often goes unnoticed compared to other vitamins and minerals — yet its benefits are significant.

What Makes Selenium Important?

Selenium functions as a powerful antioxidant, helping the body create enzymes that regulate thyroid metabolism, DNA synthesis, and immune response. It supports healthy cell growth and protects tissues from damage caused by oxidative stress, which can lead to heart disease, cancer, and other chronic conditions.

Because the body cannot produce selenium on its own, it must be obtained from food or supplements. However, maintaining the right balance is key — too little can lead to thyroid and immune issues, while too much may cause toxicity.

Recommended Daily Selenium Intake

According to the National Institutes of Health (NIH), the recommended daily intake of selenium depends on age and health status:

• Adults: 55 micrograms (mcg)
• Pregnant women: 60 mcg
• Lactating women: 70 mcg

The upper limit for adults is 400 mcg per day. Exceeding this limit can cause selenosis — a condition marked by hair loss, brittle nails, fatigue, and nervous system problems.

Top Selenium-Rich Foods to Add to Your Diet

If you want to boost your selenium intake naturally, here are some of the best foods to include in your meals.

1. Brazil Nuts

Brazil nuts are one of the richest sources of selenium in the world. Just two nuts contain around 190 mcg, which is more than 300% of the recommended daily intake. They’re also packed with magnesium, copper, and heart-healthy fats. However, moderation is essential — eating too many can lead to selenium toxicity.

2. Tuna

Tuna is both nutrient-dense and protein-rich. A 4-ounce serving of canned light tuna provides about 80 mcg of selenium, along with vitamin B12 and B6, which support energy metabolism and nerve health.

3. Oysters

Six raw oysters deliver roughly 50 mcg of selenium — nearly the full daily requirement. They’re also loaded with zinc, iron, copper, and vitamin B12, making them an excellent food for immune support.

4. Sardines

Canned sardines provide around 48 mcg of selenium per serving. They’re affordable and rich in omega-3 fatty acids, calcium, and vitamin D, which promote heart and bone health.

5. Shrimp

Three ounces of cooked shrimp supply 42 mcg of selenium. Shrimp are also a good source of lean protein, iodine, and antioxidants like astaxanthin, which supports skin and brain health.

6. Pork Chops

A 3-ounce serving of pork chops contains about 38 mcg of selenium. Pork is also a source of high-quality protein, iron, and creatine — beneficial for muscle repair and performance.

7. Portabella Mushrooms

Vegetarians can get a selenium boost from mushrooms. One cup of grilled portabella mushrooms provides 26 mcg, plus antioxidants, fiber, and essential minerals like potassium and copper.

8. Turkey

Three ounces of turkey breast contain around 26 mcg of selenium. This lean protein option also delivers vitamins B6 and B12, which help convert food into energy and support nerve function.

9. Eggs

One hard-boiled egg provides about 15 mcg of selenium. Eggs are rich in choline, a nutrient that promotes brain health and supports liver function.

10. Cottage Cheese

A cup of low-fat cottage cheese contains 20 mcg of selenium and more than 12 grams of protein. It’s also high in calcium and B vitamins that strengthen bones and boost metabolism.

11. Brown Rice

A cup of cooked brown rice offers 12 mcg of selenium. It’s a fiber-rich whole grain that supports digestion, blood sugar control, and heart health.

Balancing Selenium Intake Safely

Most people get enough selenium through their diet without supplements. However, those who live in areas with selenium-deficient soil or follow restrictive diets should be mindful of their intake. Consulting a healthcare professional before starting any selenium supplement is highly recommended.