Selenium is one of the 118 chemical elements known to human beings. It is a ‘non-metal’ element discovered in the year 1817. It is not available in its elemental form in the earth’s crust, it is present only in the form of metal sulfide ores. Selenium is present in plants in the form of different chemical compounds. It is present in many minerals excavated from the ground. Selenium provides important medicinal as well as non-medicinal benefits.

Besides being a vital nutrient for the human body, it has a number of industrial uses. Some of the industrial uses are in the manufacture of alloys, photo-conductors, electrolysis of manganese, lithium batteries /solar cells and in the production of glass.

It is an essential nutrient needed for maintaining healthy joints, heart and eyes in human beings. The sources of selenium for the body is either through water or through various food consumed. But majority of it is obtained from the food.

Sources of Selenium

Selenium is available in varies allotropic forms (structural formations). Generally it is sourced in the form of red powder or glassy and black or a metallic crystal. Barring the dietary forms, reference to various physical forms of selenium, is only of academic interest here as they cannot be directly used as sources of selenium for internal consumption.

The quantity of selenium present in plants is based on the geographical region and soil where it is grown. Performance of antioxidants in the body is enhanced by the presence of selenium. This particular function of selenium makes it an essential and vital element required by the body.

Dietary form of the element is sourced from wheat, mushrooms, nuts and cereals. Fish, poultry products, crab and liver are also good sources of the mineral. Brazil nuts are considered to be the best source of selenium, as the soil of the region itself enhances the selenium content of the plant grown on it. Moreover, Brazil nut does not require much of selenium for its own growth.

Selenium deficiency in the body may lead to a number of disorders including heart problems and mental disorder. The chemical compound called selenoproteins derived from selenium is essential for the biological functions. Selenoenzymes play effective role in regulating the performance of the metabolic system. Their role in the embryonic development is significant.

Health Benefits of Selenium

It is used in curing a number of health disorders.

  • It is used in treating different heart related problems like thickening of arteries and stroke.
  • Used in the treatment of various types of cancers found in lungs, prostrate, skin and stomach.
  • It is known to promote healthy joints, protect the heart and maintain a healthy vision by preventing macular degeneration.
  • Some of the critical health issues due to head injury and burns are cured by the use of selenium.
  • It enhances the performance of the immune system and the reproductive system.
  • It plays a significant role in DNA synthesis.
  • The element is used to treat arsenic poisoning and to prevent miscarriage.

The potential of the element in enhancing the function of antioxidants, makes it vital in addressing the health issues broadly outlined above. Significant benefits of the mineral are elaborated for better understanding of its need for the human body.

Prevents cancer

Selenium is considered a miracle mineral which combats cancer. It strengthens the immune system of the body and improves the anti-cancer abilities when administered in higher doses. Any damage occurring to the DNA system, is repaired by adequate use of selenium. Damage to DNA causes mutation of cancer cells as well as tumor growth. Selenium prevents the occurrence of these two problems. (1)

Also incidence of cancer in the liver, lungs, stomach, skin and prostrate are prevented by appropriate administration of selenium into the body. In fact, it not only prevents the occurrence of cancer but also retards the growth of already existing cancer cells and tumors. The importance of selenium for the body can be well understood by the fact that people living in regions where the soil is deficient in selenium, are more prone to cancer when compared to others who live in areas where the selenium content in the soil is relatively high.

In addition to the direct effect of cancer prevention selenium is beneficial in the reduction of side effects due to chemotherapy performed in the treatment of cancer.

Protects the heart

Coronary heart diseases are cured by higher dosages of selenium intake. Cardiovascular diseases are caused due to imbalance between the capacity of the coronary vessels to supply adequate blood flow and the requirements of the myocardial functions (muscle tissues of the heart are known as myocardia).

In order to protect the heart from such coronary diseases either consumption of selenium rich food or supplements is recommended. Antioxidant properties in it reduces the oxidative stress and also fights against inflammatory tendencies which eventually prevents heart ailments. Moreover, it increases the blood flow and protects the heart by preventing hardening of the arteries. A word of caution, studies undertaken in finding out the significant benefits of selenium in preventing heart diseases have still not conclusively established the benefits. Some studies have confirmed that when selenium is consumed in combination with beta-carotene and vitamin E, higher levels of cholesterol is normalized, which is important to protect the arteries. (2)

Regulates thyroid

Selenium in the body activates thyroid metabolism. Secretion of adequate thyroid hormones is essential for the process of metabolism and also to regulate the calcium level in the blood.  The catalytic function of selenium in the production of thyroid hormones, make it essential, in order to maintain the overall health of the body.

Provides psychological health

Many psychological issues caused due to stress, mental strain and physical weaknesses are treated by administering appropriate dosage of selenium. Such inclusion of the mineral into body can be through foods or as supplements. In either case, the immune system of the body functions effectively and reduces stress/ other psychological disorders. In fact, mood disorders and chronic fatigue syndrome are treated with particular supplements. It is considered as a mood enhancer in normal people and as a stress/anxiety reducer in mentally challenged patients. (3)

Beats infertility

By increasing the blood flow and enhancing the mobility of sperms, it is helpful in addressing fertility issues suffered by men. It is helpful in the formation and further development of the sperm in addition to ensuring its motility. It is observed that it may even prevent miscarriage in women. More particularly, the miscarriage occurring during the first trimester is attributed to deficiency of the element. However, researches in this direction are being carried out to conclude its effect. (4)

Boosts overall health

Circadian Rhythm of the body, which is most important for overall health, is regulated with the help of selenium. Circadian rhythm is the recurrence of the biological process, at regular intervals, which is required for hormone secretion, drug sensitivity, sleeping, feeding, etc,.

Reduces oxidative stress

Being an antioxidant, it reduces the oxidative stress. It has the ability to reduce or prevent the damage caused by free radicals produced in the body during metabolism. Consequently, it slows down the ageing process. Some studies have confirmed that the cognitive functions in elders increase with high amounts of selenium levels. It increases the insulin like growth factor, a particular hormone, required for appropriate growth from childhood.

Cures asthma

It has been established that people suffering due to chronic asthmatic conditions, have relatively lower level of selenium. When you consume increased dosages of selenium, you can see drastic changes in the severity of asthma.

Reduces aggression of infections

Deficiency in this mineral leads to aggression of viral infections. Hence medicines administered to treat infections, must also be accompanied with adequate intake of selenium either through food or through supplements. You also need to cautious that it is not lead to over dosage.

Some studies have observed that adequate intake of the mineral for about ten years, has the potential to decrease the risk of death in patients suffering from lung, prostate, HIV and colorectal cancer.

As a word of caution, it is important that you ensure the consumption of Required Daily Amount (RDA) which is 400 mcg per day. At the same time, you should not go for supplements without consulting the physician or without finding out the selenium level in the body.

While permitted quantity is vital for the overall health of the body and to treat particular disorders, excessive consumption of the mineral is known to cause type 2 diabetes. It not only increases blood sugar, it also reduces secretion of a particular thyroid hormone. Moreover, excessive consumption of the mineral could aggravate prostate cancer mortality.

Overdose of the mineral may cause disorders in the digestive system, neurological issues, sore muscles and sometimes breathing difficulty. In rare cases, it may even lead to death.

You need to focus on one more important caution. The protective ability of the element is yet to be proved and there are recordings to suggest the opposite like increasing the risks of certain types of cancers in skin and prostate.



Kripa Sivasubramanian, MBA, earned her Master’s degree in Business. After a long stint in the Technology sector, she took up courses in natural medicine and yoga. Ms. Kripa is certified in Ayurvedic yoga for Dosha. She is also certified by Stanford University School of Medicine in Introduction to Food and Health.