Selenium – Benefits, Deficiency, and More

Brazil nuts are selenium rich food source
Introduction to Selenium

It is a trace mineral that is essential for human health. It is involved in a number of important physiological processes, including the proper functioning of the immune system, thyroid gland, and reproductive system. Selenium also plays a role in protecting the body against oxidative damage and preventing chronic diseases such as cancer and cardiovascular disease.

Food Sources

Some selenium rich foods are; (Selenium foods high in)

  • Seafood
  • Meat and poultry
  • Grains
  • Nuts and seeds
  • Dairy products
  • Fruits and vegetables
  • Fortified breakfast cereals are a modernized selenium food source
Benefits of Selenium

It is an essential mineral that plays a crucial role in several bodily functions. Below are some of the health benefits and what selenium used for;

  • Immune system support: It plays a crucial role in the proper functioning of the immune system.
  • Thyroid function: It is required for the proper functioning of the thyroid gland, maintains good thyroid health and symptomatically help hypothyroidism
  • Antioxidant activity: It is a powerful antioxidant, which means it helps protect the body against oxidative damage caused by harmful molecules called free radicals.
  • Cancer prevention: Some studies suggest that it may help protect against certain types of cancer, such as prostate, lung, and colorectal cancer.
  • Cardiovascular health: Selenium has been shown to help reduce inflammation, lower blood pressure, and improve blood flow, all of which can help reduce the risk of heart disease.
  • Cognitive function: Some research suggests that it may help improve cognitive function, protect against age-related cognitive decline and maintain functioning of brain. Selenium deficient individuals may have a hard time going through day- to- day tasks.
  • Male fertility: It is also important for male reproductive health and has been shown to improve sperm motility and quality. Along with zinc and various other nutrients, it is vital for men’s health.

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Recommended Dietary Intake
AgeDaily Selenium intake
0-6 months15 mcg
7-12 months20 mcg
1-3 years20 mcg
4-8 years30 mcg
9-13 years40 mcg
14-18 years55 mcg
19+ years55 mcg

*These values are a reference point for healthy individuals, consult a health care professional before any supplementation*

Deficiency Symptoms

It’s appropriate consumption of it is not bad for you. Still, selenium deficiencies are a common occurrence and the deficiency symptoms of selenium include;

  • Muscle weakness and fatigue
  • Joint pain and stiffness
  • Difficulty concentrating or brain fog
  • Weakened immune system and increased risk of infections
  • Infertility or decreased fertility
  • Hair loss or brittle nails
  • Changes in mood or behavior

Selenium poisoning from brazil nuts?

Brazil nuts contain very high amounts (65 to 90 mcg per nut) and can cause you to go over the toxic levels if you eat too many at once. Just a single piece is enough to help you get enough of selenium to reach the optimum selenium levels.


Toxicity Symptoms

While it is an essential nutrient, consuming too much selenium can lead to toxicity. Some of the symptoms of selenium toxicity include:

  • Hair loss, brittle nails, and skin rash
  • Fatigue and irritability
  • Gastrointestinal disturbances such as nausea, vomiting, and diarrhea
  • Garlicky breath odor
  • Neurological symptoms such as tremors and muscle weakness
  • Respiratory problems such as difficulty breathing and bronchitis-like symptoms



In conclusion, selenium is an essential nutrient that plays an important role in various bodily processes. As with any nutrient, it is important to consume it in moderation and in the context of a balanced and varied diet. Before supplementing, you must know if selenium supplements are beneficial in your given case. If you suspect that you have been exposed to high levels of selenium or are experiencing symptoms of selenosis, it is important to seek medical attention.


About the Author

Moaz Farhan

Doctor of Pharmacy (Pharm. D) and Content Author at KeepUpFitness.

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