Selenium is a trace element with a number of essential functions. An estimated one billion people worldwide get too little dietary selenium. The problem is mainly a result of nutrient-depleted farmland. Moreover, blood levels of selenium drop drastically in connection with COVID-19 infections, serious illness, and pregnancy because the body has an increased need for the nutrient. Altogether, selenium deficiency increases the risk of complicated COVID-19 infections, autoimmune diseases such as rheumatoid arthritis, Hashimoto’s thyroiditis, preterm delivery, and miscarriage. Supplementation may help optimize blood levels of selenium, which can be relevant for preventing and treating a number of common diseases, according to an article that is published in International Journal of Medical Sciences.
Selenium is an essential trace element that supports over 25 different selenoproteins that are important for our energy turnover, immune defense, metabolism, pregnancy, and fertility. Selenium is also a constituent element of various antioxidants (the so-called GPXs) that protect our cells, tissues, cholesterol and cardiovascular system against oxidative damage caused by free radicals. Our selenium metabolism is extremely complicated and selenoprotein P is used as a marker of the body’s selenium status.
Our dietary selenium intake is contingent on the natural selenium content in soil, which in itself can vary by several hundred percent from one part of the world to another. Intensified farming methods can result in additional nutrient depletion of our soil and this can affect the entire food chain. WHO has reported that the selenium levels are low in over 40 countries, with the lowest levels in Europe, Africa, and China. An estimated one billion people worldwide are believed to be selenium-deficient.
Professor Lutz Schomburg, a selenium researcher who is affiliated with the Charité-Universitätsmedicin in Berlin and the author of the new article, looks closer at why severe selenium deficiency often follows in the wake of COVID-19 infections, serious diseases, and pregnancy. He also looks at why these increasing selenium deficiency problems are a vicious cycle that increase the risk of complicated COVID-19 infections, slow recovery, autoimmune diseases like rheumatoid arthritis, thyroid diseases like Hashimoto’s and Graves’ disease, and problematic pregnancies and miscarriages.
Lutz Schomburg compares the fatal consequences of selenium deficiency to those seen with iodine deficiency, where health authorities learned a long time ago to enrich table salt with iodine as a way to avoid iodine deficiency diseases. With regard to peoples’ selenium intake, Finland has made a noteworthy precedent in Europe by introducing mandatory selenium enrichment of agricultural fertilizers back in 1985 as a way to prevent deficiency ailments. This policy affected the entire food chain and resulted in a rapid increase of the Finnish population’s selenium status. Other than that, selenium deficiency among humans, unfortunately, is a global and overlooked problem with fatal health consequences.
1: Selenium, immune defense, and COVID-19
Selenium supports a host of different selenoproteins that are of importance to our innate immune defense that helps us fight pathogens in the background. Selenium is also important for the immune system’s ability to communicate and for the adaptive immune defense that can specialize, form antibodies, and immunity. Selenium is also a constituent in different antioxidants (GPx) that protect healthy cells against free radical attacks. That way, selenium is able to counteract unwanted inflammation, oxidative stress, and damage to cells and tissue.
Selenium also prevents virus from mutating and becoming more dangerous. A team of Chinese scientists has reviewed multiple studies concerning selenium’s key role in the fight against influenza, HIV, and other types of RNA virus. It appears that the risk of contracting a COVID-19 infection is 10 times lower in areas where the selenium levels in the soil are high. Also, a German report shows that survivors of COVID-19 have higher blood levels of selenium compared with patients that died of their infection. During the infection period, the levels of selenium in the blood drop drastically because the nutrient is used to fuel the activity of white blood cells and also supports the body’s antioxidant defense.
2: Selenium and cardiovascular disease
Keshan disease is a lethal heart disease that was originally discovered in the Keshan province in the northeastern part of China. Here, levels of selenium in the soil are extremely low. Keshan disease is caused by a normally harmless virus named Coxsackie, which the immune defense is unable to defeat without the presence of selenium. As early as in 1965, the Chinese population in this region started using selenium supplements to prevent and eradicate the much-dreaded disease.
Over the last decades, numerous studies have shown that selenium deficiency also increases the risk of blood clots and sudden cardiac death, while selenium supplementation protects against atherosclerosis. Because ageing processes are often linked to oxidative stress, they automatically increase the need for protective antioxidants like selenium. In the groundbreaking Swedish, KiSel-10 study, where a group of healthy seniors were given placebo or selenium yeast with coenzyme Q10, those in the treatment group had 54 percent lower cardiovascular mortality compared with the control group. In follow-up studies conducted 10 and 12 years later, the scientists were still able to observe a protective effect among those who had been given selenium yeast and coenzyme Q10. Nonetheless, cardiovascular disease is the leading cause of death and is associated with oxidative stress, a phenomenon that sets the stage for other diseases.
3: Selenium and pregnancy
The selenium-containing proteins have a particular structural role during pregnancy and contribute to the development of the brain, other organs, and tissues of the fetus. The GPx antioxidants that also contain selenium protect the placenta and the fetus against potentially damaging oxidative stress. It has also been demonstrated that selenium levels in the uterus are increased in the final stage of pregnancy due to the increased need for the nutrient. Lack of selenium during pregnancy can result in oxidative stress and low birth weight, which may have consequences for the baby’s development, cognitive skills, and health in general.
Pregnant women who take a daily supplement with 100 micrograms of selenium from the first trimester until delivery can lower their risk of a ruptured fetal membrane by around 30 percent, according to a study that is published in Journal of Obstetrics and Gynaecology.
It was also seen that pregnant participants that took supplements of selenium yeast had a lower rate of preeclampsia, which is the leading cause of preterm delivery. Preeclampsia can also lead to a life-threatening condition called eclampsia. Not only can a selenium deficiency take its toll on a healthy pregnancy, it may also increase the risk of maternal deficiency symptoms.
|A table from the new article shows that bacterial infections, virus infections, cancer, burn injuries, smoking, surgery, transplantations, and pregnancy all lower the body’s selenium status, which increases the risk of autoimmune diseases|
4: Selenium and autoimmune thyroid disorders
As mentioned, nutrient-depleted soil contributes to the widespread selenium deficiency problem. In addition, infections, chronic diseases, pregnancy, and ageing processes deplete the body’s selenium reserves, thereby increasing the risk of deficiency problems. This can lead to oxidative stress, unwanted inflammation, and autoimmune diseases where the immune defense attacks the body’s own tissues. An example is Hashimoto’s disease that results in slow metabolism. This condition causes the immune defense to attack the thyroid gland that produces thyroid hormones. This insidious disease which is quite widespread is linked to selenium deficiency.
Graves’ disease, another autoimmune disease, causes an elevated metabolic rate. Here, the immune system attacks the part of the thyroid gland that binds TSH – or thyroid-stimulating hormone – causing an overstimulation of the thyroid gland.
The reason that a selenium deficiency increases the risk of thyroid disorders is that this particular nutrient is of vital importance to the thyroid gland. It enables us to convert passive T4 hormone into active T3 hormone with help from a selenium-containing enzyme called deiodinase. Moreover, the selenium-containing GPx antioxidants protect the thyroid gland against oxidative stress caused by a large flow of blood through the organ.
Several studies have shown that supplementing with 200 micrograms of selenium per day has a positive effect with regard to preventing and treating several types of thyroid disease.
Lutz Schomburg refers to two relatively large Danish studies (CATALYST and GRASS) where 200 micrograms of selenium were administered to thyroid patients who did not respond to their medical treatment. So far, it appears that this dose is adequate for patients with thyroid disorders.
5: Selenium, rheumatoid arthritis, and type 1 diabetes
Rheumatoid arthritis is a chronic autoimmune disease where the immune defense attacks the joint tissue in hand, feet, and wrists, eventually leading to cartilage damage and bone erosion. The inflammatory processes can also spread to other tissues. Rheumatoid arthritis is more common among women than among men and can cause impaired quality of life and increased mortality.
Patients suffering from rheumatoid arthritis have been found to have low selenium levels in their blood. This can lead to the formation of pro-inflammatory cytokines such as IL-6 and IL-1β. Only few studies have been conducted with rheumatoid arthritis and selenium supplementation. In one study where 200 micrograms of selenium yeast were given daily for 90 days, scientists observed an increase in blood selenium levels. Also, several disease parameters improved, including quality of life.
Type 1 diabetes is an autoimmune disease where the immune defense attacks the insulin-producing cells in the pancreas. Although type 1 diabetes is rather common and selenium’s role in the immune system and the hormone system is established, there is only a limited amount of research that involves selenium and diabetes.
Selenium is vital for a well-functioning immune system. However, selenium deficiencies are very common in Europe and in other parts of the world, mainly due to the nutrient-depleted farmland. Blood levels of selenium also plummet in connection with COVID-19 infections, serious disease, and pregnancy and that increases the risk of serious complications. In addition, having too low selenium status increases the risk of autoimmune diseases, especially thyroid disorders like Hashimoto’s and Graves’ where the immune defense attacks the thyroid gland. Selenium supplementation is strongly recommended in situations with acute or chronic selenium deficiency, whereas people with adequate selenium levels in the blood and no immediate signs of being selenium-deficient normally don’t need to supplement with the nutrient. The new article is published in International Journal of Molecular Sciences.
Selenium sources, official recommendations, and optimal intake
We get selenium from fish, shellfish, organ meat, eggs, dairy products, and Brazil nuts. Selenium deficiencies are widespread in Europe because of the low selenium in crops that have been cultivated in selenium-depleted farmland and because diets have changed. The reference intake (RI) for selenium is 55 micrograms per day (in Denmark), but research shows that this quantity if not enough to effectively saturate selenoprotein P, a selenoprotein that is used as a marker of the body’s selenium status. In order to reach full saturation, one must get at least 100 micrograms of selenium every day. Selenium yeast with a variety of different organic selenium types provides the same natural blend of selenium species that you get by eating a varied diet. The European Food Safety Authority (EFSA) has set 300 micrograms as the safe upper intake level for selenium. It is recommendable, no matter what, to strive to eat a balanced diet because the different selenoproteins work in synergy with vitamin E, among other things.
|Important selenium-containing compounds|
|Deiodinase type 1-3||Thyroid hormones|
|GPX 1-6 (glutathione peroxidase)||Powerful antioxidants|
|Selenoprotein S||Regulation of cytokines and cellular inflammatory response|
|Selenoprotein P||Antioxidant and selenium transport in the body|
|Selenoprotein R and N1||Antioxidants with several other functions|
|Selenoprotein M||Large concentration in the brain. Its function is not fully understood|
|Selenoprotein T||Involved in cell construction and proteins|
|TXNRD 1-3||Antioxidants, mitochondria, energy turnover, metabolism|
|MSRB1||Repair of oxidative damage|
|Even minor selenium deficiencies can result in sub-optimal functioning of selenoproteins|
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