Remember to get enough selenium for your immune defense - throughout life

Remember to get enough selenium for your immune defense - throughout lifeThe immune system needs selenium every single day. Lack of this nutrient increases your risk of virus infections, inflammation, and cancer. It is a huge problem that many of us get too little selenium because of factors such as nutrient-depleted soil and unhealthy eating habits.

Selenium is a constituent of 25-30 different selenoproteins that have many vital functions. Numerous studies reveal that an increased selenium intake can activate the innate and adaptive immune systems that include various types of white blood cells and antibodies. Moreover, selenium is an important antioxidant that protects cells against free radicals and inflammation. The big question is: How much selenium do we actually need in order to be optimally protected against infection, cellular damage, and cancer.

Selenium supplements strengthen the immune system

An American study demonstrated how supplementation with 200 micrograms of selenium increased the activity of a type of white blood cells called "killer cells" by 118% and NK cells (natural killer cells) by 82%. This increase provides better protection against infections and cancer.

White blood cells use free radicals as ammunition

The moment we get an infection, our white blood cells take up large quantities of oxygen that is converted into free radicals. The white blood cells use these free radicals as lethal missiles against the intruding microorganisms. The process is known as "respiratory burst reaction" and can be translated into a respiratory explosion. When the body carries out these swift and direct attacks with free radicals, it needs selenium. One of selenium's functions in this context is to engage its antioxidant properties to limit the damage caused by the free radical impact.

If the body is properly supplied with selenium and other nutrients, the immune system will normally be able to fight a beginning infection without us noticing anything.

Selenium prevents influenza and other types of virus from mutating

Selenium prevents virus from mutating and deceiving the immune defense. RNA virus that is known to cause influenza, colds, herpes, HIV, and Ebola etc. has a particular ability to mutate, which is why selenium plays a highly important role in preventing and fighting these infections.
It is hardly a coincidence that new and dangerous flu strains often originate from large, selenium-depleted parts of China.

Life-threatening virus and selenium deficiency

In the Keshan province of the north-eastern part of China where the soil is extremely low in selenium, researchers discovered a lethal heart disease that has been dubbed Keshan disease. It is caused by an otherwise harmless virus called Coxsackie, which the immune system is unable to fight without selenium. The Coxsackie may also lead to rheumatism and cancer, which is why the Chinese in that area started preventing and eradicating the feared disease with selenium supplements way back in 1965.

The knowledge about Keshan disease inspired the American researcher Melinda A. Beck to conduct a number of groundbreaking studies. To begin with, she inoculated two groups of mice with the virus. One group had sufficient selenium, while the other group was selenium-deprived. The mice who had plenty of selenium were unaffected, while the selenium-deficient mice contracted an infection of the cardiac muscle and died. According to this study, a virus will not mutate if the host has plenty of selenium. However, once a virus manages to mutate in a selenium-deprived host, it may turn into a lethal threat to other animals and humans.

Less selenium in the soil means increased AIDS-related mortality

This was seen in an American study that compared the two factors in different states. Blood selenium levels drop long before the HIV-infected patients begin to feel sick, and it is a ticking bomb that is likely to result in a tenfold increase in AIDS-related mortality among people infected with HIV. This is a result of two things: First of all, the immune system does not function as well, but there is also too little selenium to undertake the nutrient's other vital functions in the body.
On the other hand, however, patients with higher selenium levels are expected to live longer, in spite of their disease.

Selenium and a healthy lifestyle dials down inflammation

Auto-immune diseases like rheumatism, sclerosis, type 1 diabetes, Chron's disease, and metabolic disorders such as Hashimoto's disease and Graves disease are characterized by chronic inflammation where the immune defense attacks the body's own tissues. Lifestyle diseases such as metabolic syndrome, type 2 diabetes, and cancer also involve chronic inflammation, although this is not felt directly.
Interleukin-6 is a group of substances in the body that promote inflammation. Science has observed that levels of interleukin-6 increase with selenium deficiency. Also, selenium-containing proteins called GPX inhibit interleukin-6 and therefore fight inflammation. This was seen in a Danish study from Århus University where selenium supplements successfully increased GPX activity in patients with rheumatoid arthritis. For decades, Danish farmers have fed selenium to their pigs as a way of preventing inflammation in the joints of the animals.

Chronic inflammation is seen with most types of chronic disease in western cultures. It causes free radicals that can damage healthy cells and exhaust the body.

Selenium yeast prevents cancer

Countless international studies over the past decades have shown the cancer-protective role of selenium. For instance, the American scientist Larry Clark conducted the so-called NPC study (Nutritional Prevention of Cancer) and showed that daily supplementation with 200 micrograms of selenium yeast was able to reduce cancer mortality by 50%. According to this, millions of people would be able to survive or avoid cancer if they got more selenium.
People often refer to a later study known as the SELECT study, but this study was unable to demonstrate a cancer-protective effect of selenium. This is because the researchers used a form of selenium called selenomethionine, which is less effective. It is therefore recommended to use organic selenium yeast.

Lower selenium levels predict disease

A difference in blood levels of selenium can be detected between healthy individuals and cancer patients long before the disease actually manifests itself. Because cancer normally takes many years to develop, selenium is believed to be an important element in long-term cancer prevention.

Selenium's six anti-cancer mechanisms

  • Powerful antioxidant that protects cells against free radicals
  • Repairs DNA damage
  • Inhibits the formation of new blood vessels in tumors (angiogenesis)
  • Causes diseased cells to self-destruct (apoptosis)
  • Contributes to a well-functioning immune system
  • Regulates the production of substances that can overstimulate the immune defense

Selenium supports the ageing immune system

Ageing is a complicated process that involves free radicals and changes in the metabolism, hormonal system, and immune system. In a study of healthy, elderly people (57-84 years of age), daily supplementation with beta-carotene (45 mg) and/or selenium (400 micrograms) for six months led to interesting results. Selenium alone caused levels of white blood cells (CD4 T cells) to increase by over 50 per cent. This increase lasted for two months after the study participants had discontinued their use of the supplements.
Selenium is also an important antioxidant, and many studies have shown that selenium plays a vital role when it comes to maintaining a strong immune defense and good health in older people

Selenium's function in the immune defense

  • Helps white cells produce free radicals that are used to attack microbes and cancer cells
  • Functions as an antioxidant that prevents free radicals from damaging healthy cells
  • Contributes to fast cell division and communication between cells
  • Prevents virus from mutating
  • Counteracts undesirable reactions and inflammation, which is seen with most chronic disease


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Hagemann-Jensen Michael et al. The Selenium Metabolite Methylselenol Regulates the Expression of Ligands That Trigger Immune Activation through the Lymphocyte Receptor NKG2D. The Journal of Biological Chemistry. 2014.

Klein EA et al. Vitamin E and the risk of prostate cancer: The Selenium and Vitamin E Cancer Prevention Trial (SELECT). Jama 2011.

Bleys J et al: Serum selenium levels and all-case cancer, and cardiovascular mortality among US adults. Arch Intern Med. 2008.
Arthur John R et al. Selenium in the Immune System. The Journal of Nutrition. 2003.

Hertz Niels. Selen et livsvigtigt spormineral. Ny Videnskab 2002

Beck MA, Levander OA. Host nutritional status and its effect on a viral pathogen. J Infect Dis. 2000.

Cowgill U.M. The distribution of selenium and mortality owing to acquired immune deficiency syndrome in the continental Unites States. Biol Trace Elem 1997.

Clark LC et al: Effects of Selenium Supplementation for Cancer Prevention in Patients with Carcinoma of the Skin. Journal of the American Medical Association: 1996.

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