13 Proven Benefits of Selenium

by John Staughton (BASc, BFA) last updated -

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Selenium has a wide array of health benefits, including its ability to protect against certain heart diseases, boost the strength of the immune system, maximize thyroid function, reduce inflammation, prevent cancer, reduce the signs of premature aging, protect against antibodies, boost hair health, and balance your hormones.

What is Selenium?

Selenium is an essential trace mineral that is mainly derived from soil, water, and plant materials. Humans mainly acquire it from various plant sources, and since it is required for a number of essential activities, it is considered a non-metal. Although toxic in large quantities, it is necessary for certain cellular functions of animals and people. Therefore, including selenium-rich plant material in your diet is very important for maintaining overall health and wellness.

Selenium was actually discovered accidentally in the early 19th century, as a precipitate given off in the lead chamber process that was required to produce sulfuric acid. It was originally thought to be toxic and was eliminated, but when it was burned, it gave off an unusual smell, similar to the pungent odor of horseradish. Eventually, it was recognized as an independent element, although it is quite rare and difficult to find in large quantities.

Health Benefits of Selenium

The health benefits of selenium are still being studied extensively, but certain very important advantages are already well known and are explained in greater detail below.

Prevents Cancer

As mentioned above, selenium has been found to be an essential part of a number of cellular processes, and this includes the body’s response to cancerous activity. A study published in Selenium in Biology and Human Health has shown that a normal selenium intake can result in a serious decrease in cancerous cell formation, especially in regards to prostate, colorectal, and lung cancers. Selenium is an essential player in various enzymatic reactions that can induce apoptosis, also known as automatic cell death. It specifically kills all the dangerous cancer cells, without harming healthy cells. Free radicals, the byproducts of cellular metabolism that can cause cancer, damage DNA and mutate into the cancer cells. Selenium can boost DNA repair and prevent this mutation from occurring. Finally, glutathione superoxidase, an important anti-cancer compound in the body, utilizes selenium for its activity, making it all the more important.

Bowl filled with Brazil nuts on a wooden background

Boosts Immunity

Studies have shown that selenium is important in the stimulation of antibodies, which are elements of the immune system that seek out and destroy viral, bacterial, fungal, and protozoan foreign bodies that result in diseases and infections. Selenium helps to stimulate these antibodies, particularly after you receive a vaccination for one of these diseases, making your body resilient and experienced in fighting them off so you remain healthy and protected throughout your life.

Relieves Inflammation

Apart from boosting your immune system, selenium also protects your body from wearing down and feeling older than it really is. A study in Hormone and Metabolic Research throws light on its anti-inflammatory properties. Selenium has been shown to reduce oxidative stress that often occurs around joints and bones, manifesting into the various inflammatory conditions like rheumatoid arthritis, gout, psoriasis, lupus, eczema associated pain, and weakness. By reducing the inflammation at these vital hinges of your body, you can remain active, healthy, and pain-free for many years.

Improves Thyroid Health

When it comes to the endocrine system and the regulation of hormones in the body, the thyroid gland is one of the most significant and impacting. Research cited in Endocrine Reviews has shown that selenium is an essential component of the thyroid gland’s functions and helps to regulate the amount of thyroid hormone that is produced by the body. The T3 hormone is one of the most important products of the thyroid gland, and it controls your body’s overall metabolic rate and function. Without selenium, the T3 hormone cannot be produced, which can be catastrophic to a wide variety of your body’s systems.


Selenium-rich foods can help us live a longer and healthier life. This mineral is vital to well-being as it helps promote heart health, prevents asthma, and provides the body with other amazing benefits.


A selenium deficiency is considered one of the reasons for asthma, which is why selenium supplementation is used as a treatment for this respiratory condition.


Selenium promotes sperm motility and increases the blood flow in the body. These are the two main processes responsible for conception and preventing fertility. Selenium is also shown to reduce the risk of miscarriage.


The antioxidant potential of selenium is vital for protecting overall health, as the free radicals in the body can affect you in a number of terrible ways. Free radicals can weaken or kill cells in every organ system, can result in heart diseases, kidney malfunction, digestive issues, metabolic syndrome, hormonal imbalance, and premature aging.


Selenium acts as an antioxidant and stimulates the creation of more antioxidants, thereby helping to fight off the free radicals in the body. These free radicals are associated with the aging process and are one of the primary causes of wrinkles, age spots, loose skin, weakened muscles, and a generally older appearance.

Improves Mental Health & Mood

Cognitive decline has been associated with free radical activity in the neural cortex, destroying pathways and inhibiting the proper functioning of nervous impulses. Selenium can help prevent the onset of Alzheimer’s and improve mental health and overall mood by neutralizing free radicals before they can affect you.

seleniuminfoTreats Kashin-Beck Disease

There is a particular heart condition, called Kashin-Beck disease, which affects a wide swath of the population in countries that have low selenium content. This is perhaps the most serious and noticeable effect of a selenium deficiency, and it is characterized by the death of cartilage cells and a retardation of growth, often resulting in osteoarthritis at a young age. Symptoms include joint pain, stiffness, lack of flexibility, and low range of motion, basically crippling those with severe cases. Selenium deficiency is not the only cause of Kashin-Beck, but it is certainly one of the major causes. This is confirmed in a study by Dr. Gerhard Schrauzer, et al., Biological Trace Element Research Institute, San Diego.

Improves Heart Health

Selenium works as a blood thinner, which reduces the chances of blood clots, and it is also shown to reduce the amount of LDL cholesterol that builds up as plaque in the arteries and blood vessels. That plaque can lead to atherosclerosis, heart attacks, and strokes, so selenium is a powerful booster for your overall heart health for a number of reasons.

Hair Care

Although research is still being done on this condition, it is believed that good selenium content can reduce hair loss and the excessive dry scalp that results in dandruff. In a study cited in the Journal of the American Academy of Dermatology, selenium sulfide shampoo was found to be effective in the treatment of moderate to severe dandruff.

Top Foods High In Selenium

The best sources of selenium intake for humans are mainly plants and animals, including the following:

  • Vegetarian sources: Brazil nuts are the richest source of selenium that has been discovered so far, mainly because the nut requires no selenium for its own function, but stores large quantities that can be absorbed and utilized by those who eat the nut. Other plant-based sources of selenium are spinach, mushrooms, sunflower seeds, and chia seeds. Other good sources are foods made from grains grown in selenium-rich soils, such as cereals, brown rice, white bread, and pasta.
  • Fish: Ocean fish and seafood are among the richest sources of selenium. These include halibut, tuna, crabs, rockfish, herring, and lobsters.
  • Animal products: These include animal kidneys, selenium-rich grass-fed beef, chicken breast, turkey, and eggs.

Selenium Dosage

It is important to know the proper selenium dosage for a day, as an excess of this mineral can also be harmful to the health, resulting in a selenium toxicity. The dosage, therefore, varies from age to age. Let us discuss it in detail below.

  • Toddler: 20mcg/day
  • Children (4 to 8): 30mcg/day
  • Children (9 to 14): 40mcg/day
  • Adults (above 15 years old): 55mcg/day
  • Pregnant women: 60mcg/day
  • Breastfeeding women: 70mcg/day

Side Effects

Selenium toxicity is just as dangerous as a deficiency, so be careful not to overdo your intake. Symptoms of toxicity include:

  • Bad breath
  • Gastrointestinal disorders
  • Fever
  • Nausea
  • Kidney problems
  • Fatigue
  • Irritability
  • Difficulty concentrating
  • Cirrhosis of the liver
  • Pulmonary edema, and even death

Be careful to only take what is necessary, and do not take selenium supplements if you are already on a selenium-rich diet!

About the Author

John Staughton is a traveling writer, editor, and publisher who earned his English and Integrative Biology degrees from the University of Illinois in Champaign, Urbana (USA). He is the co-founder of a literary journal, Sheriff Nottingham, and calls the most beautiful places in the world his office. On a perpetual journey towards the idea of home, he uses words to educate, inspire, uplift and evolve.

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