7.3 C
Monday, December 4, 2023

Selenium: Benefits, Food Sources, and Potential Risks

- Advertisement -
- Advertisement -

Selenium is an important nutrient, though needed in very small amounts in our body, we cannot do without it. It is used in making thyroid hormones, synthesizing DNA, and protecting against infections and oxidative damage.

It has amazing health benefits and it has to be obtained through the food we eat because our body cannot make it. It is present in every tissue in the body, most especially in the thyroid gland and the skeletal muscles.

This important mineral plays major roles in many important metabolic processes of the body, it is mostly needed to boost the functions of your thyroid and ensure normal metabolism goes on in your body.

Important Health Benefits of Selenium

It is an Important Antioxidant

Selenium acts as an antioxidant in the body. Antioxidants are molecules that protect your cells and DNA from damages caused by free radicals.

Free radicals are by-products of metabolism, they are produced by the body on a daily basis, they also have some good functions like protecting the body from diseases and they are essential for good health.

Unhealthy habits like excessive intake of alcohol, stress, smoking, and bad diet increases the production of free radicals in the body and they cause more harm than good when they are too much in the body.

Excess free radicals in the body leads to oxidative stress, this, in turn, damage your healthy cells and body. Oxidative stress also causes chronic diseases like cancer, Alzheimer’s, and heart disease.

Selenium is a powerful antioxidant that reduces oxidative stress by reducing their production. It also neutralizes excess free radicals thereby protecting your cells and DNA from the harmful effects of free radicals.

Increases lifespan

Selenium increases longevity because it protects our body, fortifies the immune system, and make sure all your vital organs and metabolism are working properly. It also treats and prevents a lot of chronic diseases thus enhancing your health and increasing how long you live.

Fights Cancer

Selenium fights cancer, it does this by reducing oxidative stress in the body. This vital mineral has the ability to prevent DNA damage, it destroys cancer cells, and fortify your immune system.

About 69 studies have shown that a high level of selenium in your bloodstream can defend your body from many types of cancer, and this selenium was obtained through food and not supplements.

Selenium supplement is also effective, it reduces side effects in people undergoing radiation therapy. It also improves the overall health and reduce radiation-induced diarrhea in women undergoing treatment for uterine and cervical cancer.

Boosts fertility

Selenium ensures healthy sperm motility, it also increase the flow of blood to your reproductive organs and ensures the optimum functioning of these organs.

Selenium affects how the sperm works and behave as they move through the vagina. Both low and high levels of selenium affect the sperm negatively. In women, selenium reduces the risks of miscarriages, and ensures healthy development of the fetus.

Prevents Heart Disease

Selenium protects your heart and keeps it healthy, research has linked a low level of selenium in the body to increased risk of coronary artery disease.

In 25 observational studies, it was noted that a 50% increase in the levels of selenium in the bloodstream led to a 24% reduction in coronary artery disease.

This essential mineral also reduce the markers of inflammation, this is one of the main risk factor of heart disease. Selenium reduces the levels of CRP, an inflammatory marker.

Selenium boosts the levels of glutathione peroxidase, a powerful antioxidant in the body. It reduces inflammation and oxidative stress and these two have been linked to the buildup of plaques in the arteries.

Atherosclerosis cause dangerous health problems like heart attacks, coronary artery disease, and strokes.


Selenium slows down the aging process, it fights aging caused by free radicals and cellular degeneration because it is a powerful antioxidant. It also prevents the signs of aging such as cognitive decline.

Protect the brain

Selenium protects the brain and prevents mental decline. Oxidative stress is the leading cause of mental problems and cognitive decline like Alzheimer’s disease.

Studies have also linked low levels of selenium in the body Alzheimer’s disease and memory problems. A study have shown that a selenium-rich Brazil nut a day improve mental functions and verbal fluency in people with mild cognitive decline.

The Mediterranean diet which is very high in selenium has been known to reduce the risks of Alzheimer’s diseases and other mental problems.


Selenium detoxifies heavy metals from the body, heavy metals are toxic pollutants, and they cause a lot of problems in the body. Increase your intake of selenium rich food to detoxify your body.

Critical for Thyroid Health

Selenium is very important for your thyroid health, it helps these important glands function properly. Selenium is located in the thyroid gland in very high quantities than in any other part of your body.

Your thyroid gland produces thyroid hormones which are important for a lot of biochemical processes in the body. It controls the growth and development of your body and it also regulates metabolism.

Selenium protects your thyroid gland against oxidative damage, it ensures a healthy thyroid gland which is important for optimum health.

A deficiency of selenium has been linked to a lot of thyroid problems like Hashimoto’s disease, hypothyroidism, and autoimmune thyroiditis.

Regular intake of selenium-rich foods reduces the levels of thyroid antibodies, it also hasten healing and relieves the symptoms of Hashimoto’s disease, a type of hypothyroidism which occurs when your immune system attack your thyroid gland.

Fights Sleep Disorders

Selenium fights sleeplessness and help to reset your circadian rhythm. It helps to synchronize your internal clock to the natural light and dark cycles of the earth.

It restores a damaged circadian rhythm, thus helping to treat insomnia and other forms of sleep problems. This will help you know when to sleep and when to wake up.

Fortifies your Immune System

The immune system protects your body and keeps it healthy, selenium empowers your immune system by reducing oxidative stress and inflammation, the two main wreckers of a healthy immune system.

High levels of selenium in your bloodstream also enhance your immune response and a deficiency in selenium negatively affects your immune system by leading to a slower immune response.

A deficiency in this important mineral has been linked to increased progression of HIV and high rate of death among those with the virus.

Increased intake of selenium-rich foods and supplements improved their condition and led to fewer hospitalizations. Selenium also helps people with hepatitis C, tuberculosis, Influenza, and HIV by fortifying their immune system.

Fights viruses

Selenium empowers your immune system to fight viruses, the most stubborn microbes. A lack of selenium in your body will make your body susceptible to the weakest of viruses.

Selenium helps your body produce antibodies and it also protects the cells of your immune system. Low levels of selenium will weaken your immune response, empower viruses and trigger faster division of their cells.

Relieves Symptoms of Asthma

Asthma is an inflammatory disease that affects your airways, they become inflamed and start getting narrow; this leads to symptoms like difficulty breathing, wheezing, shortness of breath, coughing, and tight chest.

Asthma can be caused by inflammation and oxidative stress. Selenium has the ability to reduce oxidative stress and prevent inflammation. This makes it an effective natural remedy for asthma.

Research has also shown that people with asthma have low levels of selenium in their bloodstream and when it was increased, they had better lung functions.

Treats Mood Swings and Anxiety

Selenium is very important for your nervous system, it improves its functions and support the cells of your nervous system. Even a mild deficiency in selenium can affect your nervous system negatively.

It will lead to moodiness, severe mood swings, anxiety, tension, and nervousness by reducing the production of neurotransmitters in your body.

Low levels of selenium in the body have also been linked to mental confusion, depression, fatigue, anxiety, and inability to coordinate self.

These conditions will improve when selenium supplements are given to the patients for 5 weeks. It will improve their mood, they will have increased energy, less anxiety, and reduced depression.

Causes of Selenium Deficiency

  • Not taking selenium-rich foods
  • Kidney diseases
  • Alzheimer’s disease
  • Inflammatory bowel disease like Crohn’s disease and ulcerative colitis which affects the ability of the body to absorb selenium from foods
  • Long-term parenteral nutrition (people who receive food through their veins regularly will be deficient in selenium)
  • Thyroid problems

Some drugs can also lead to a deficiency in selenium, some of them are:

  • Drugs used to fight inflammation such as corticosteroids
  • Birth control pills
  • Medications used to treat schizophrenia

Consequences of Selenium Deficiency

  • Keshan disease: This disease is characterized by the abnormality of the heart muscles and it is caused by the lack of selenium in the body.

Some years back, this caused many childhood deaths in China until it was discovered to be caused by lack of selenium in the body. Selenium supplements were administered and the children recovered.

  • Kashin-Beck disease: This is another disease caused by a deficiency in selenium and it affects mostly the joints and bones.
  • Myxedematous endemic cretinism: This disease caused by lack of selenium in the body causes intellectual disability.
  • Iodine deficiency
  • Miscarriage
  • Sperm problems
  • Rheumatoid arthritis
  • Anemia
  • Muscle weaknesses
  • Progression of HIV to AIDS as a result of weak immune system
  • Various cancers

Natural Sources of Selenium

There are many natural foods with rich content of selenium, below are some of them:

  • Brazil nuts: This is one of the richest sources of selenium on the planet, there are 5 grams of selenium in one nut, and this should make up 137% of the RDI.
  • Sardines: 4 sardines contain 48 grams of selenium, making 36% of the RDI.
  • Halibut: There are 159 grams of selenium in 6 oz of halibut making 106% of the RDI.
  • Eggs: 2 large eggs contain 100 grams of selenium, making 44% of the RDI
  • Yellowfin tuna: 85 grams of selenium is contained in 3 oz making 77% of the RDI
  • Chicken: 5 oz of chicken contains 140 grams of selenium making 50% of the RDI
  • Oysters: 3 oz of oysters contain 85 grams of selenium making 77% of the RDI
  • Shiitake mushrooms: A cup of this mushroom contains 145 grams of selenium making 51% of the RDI
  • Sunflower seeds: 2 oz of sunflower seeds contain 56 grams of selenium making 62% of the RDI
  • Brown rice: A cup of cooked brown rice contains 19 mcg of selenium
  • Whole wheat bread: A slice of whole wheat bread contains 10 mcg of selenium

The concentration of selenium in plants varies and this greatly depend on the type of soil they were farmed. This is why you have to take variety of diets so you can be sure of having a high intake of selenium.

Symptoms of Selenium Deficiency

  • Depression
  • Weaknesses
  • Anxiety
  • Confusion
  • Weak immune response
  • Reproductive problems
  • Tiredness

These symptoms can persist for a long time, you have to see a doctor if you are experiencing any of these.

Dangers of Excessive Intake of Selenium Supplements

It is not possible to get excess of selenium from plant-based foods, so you don’t have to worry. You should only be careful with supplements because they can lead to selenium toxicity which has its own adverse side effects which are unpleasant.

The recommended intake of selenium per day is 55 mcg and the tolerable upper limit is 400 mcg per day. Make sure you take your supplements according to the doctor’s prescription to prevent health complications.

Some of the health complications that could arise as a result of supplement-induced selenium toxicity are:

  • Falling hair or hair or hair loss
  • A metallic taste in your mouth or your breath smells like garlic
  • Muscle soreness
  • Brittle nails
  • Dizziness
  • Stomach pain
  • Decaying or mottled teeth
  • Tremors
  • Low blood pressure
  • Gastrointestinal problems
  • Nausea and vomiting
  • Fast heart beat
  • Irritability, fatigue, and extreme weakness
  • Facial flushing
  • Skin rashes and lesions

In severe cases of toxicity, you will notice the following symptoms:

  • Kidney failure
  • confusion
  • Serious intestinal problems
  • Skin cancer
  • Heart attack
  • Delirium
  • Neurological problems
  • Coma
  • And sometimes death.

Make sure your supplement is prescribed by a medical doctor and you have to get it from a reputable health store.

These supplements can also react with medications like cisplatin and chemotherapy drugs. You have to discuss with your doctor before taking this supplement.

Recommended Dosage for Selenium Supplements

Below are the recommended dosages:

  • Infants from 0 to 6 months are to take 15 micrograms daily
  • Infants from 7 to 12 months are to take 20 micrograms daily
  • Children age 1 to 3 are to take 20 mcg per day
  • Children age 4 to 8 are to take 30 mcg per day
  • Children age 9 to 13 are to take 40 mcg per day
  • Men aged 14 and above are to take 55 mcg per day
  • Women aged 14 and above are to take 55 mcg per day
  • Pregnant women are to take 60 mcg per day
  • Breastfeeding women are to take 70 mcg per day.


  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3614697/
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2835914/
  3. https://www.ncbi.nlm.nih.gov/pubmed/20133068/
  4. https://www.nhlbi.nih.gov/health/health-topics/topics/atherosclerosis
  5. https://www.ncbi.nlm.nih.gov/pubmed/17030648
  6. http://online.liebertpub.com/doi/abs/10.1089/thy.2009.0351
  7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3066516/
  8. https://www.ncbi.nlm.nih.gov/pubmed/12061082
- Advertisement -
Faith Ebiojo David
Faith Ebiojo Davidhttps://naturecuresus.org/
Hi, It's nice having you here viewing my post. I am Faith but friends call me Ebi, I am a naturopath and writer. I love writing on health and anything that educates people.
- Advertisement -
- Advertisement -
- Advertisement -
Notify of

Inline Feedbacks
View all comments