Selenium

Dr. med. Heinz Lüscher

What is selenium?

Effects

The mechanism of action of selenium is extremely diverse. It plays a key role in various biochemical processes that are crucial for health and homeostasis, i.e. a healthy physical balance. Selenium is essential for the function of at least 25 enzymes in the body, which are found in almost all organs, so a deficiency can cause disorders in various organ systems. Enzymes from the group of glutathione peroxidases, for example, which play an important role in the fight against oxidative stress, are selenium-dependent. Deiodases are also important for the action of thyroid hormones in the body’s cells.

The most important functions:

• Antioxidant effect: It is a central component of enzymes such as glutathione peroxidases, which protect the cells from oxidative stress
• Supporting the immune system: It supports immune function by modulating and controlling the formation, growth and activity of immune cells
• Thyroid hormone metabolism: It is responsible for converting the inactive thyroid hormone thyroxine (T4) into the active form triiodothyronine (T3)
• DNA synthesis / repair: It is involved in DNA synthesis and plays a role in the repair of DNA damage
• Apoptosis: It can influence programmed cell death

Selenium as an antioxidant

As a so-called antioxidant, selenium protects the body’s cells from dangerous free radicals. These can enter the body from the outside, e.g. through environmental pollutants, nicotine, alcohol, ozone, medication, etc., but they also arise from inflammation within the body. These aggressive free radicals first attack the cell walls, then enter the body and can destroy the entire cell. In this way, a whole range of chronic diseases take their course, including cardiovascular diseases, dementia, cancer and many more. Diseases that are associated with chronic inflammation, such as autoimmune diseases, are kept going by free radicals. A low selenium level can often be measured in the diseases mentioned, which should definitely be balanced with a suitable selenium product. There are numerous studies that prove the protective effect of selenium on various types of cancer. An optimal supply of selenium protects the body’s cells from cancer-promoting substances and is used individually in high doses as an accompanying treatment for oncological therapy. Side effects of chemotherapy, such as inflammation of the mucous membranes, can also be alleviated or even avoided, and the immune system is strengthened.

Support for the immune system

Selenium can relieve and support the immune system through its antioxidant effect. Viruses in particular, for example, cause strong oxidative stress in the body, which can be tackled by selenium and the infection thereby alleviated. It also binds various heavy metals, creating poorly soluble complexes in which the heavy metals can no longer harm the body. Selenium also stimulates the production of antibodies. T lymphocytes and natural killer cells, immune cells that are part of the adaptive (acquired) immune response, are increasingly formed and activated. In this way, pathogens are eliminated more quickly and infections are overcome. A selenium deficiency, on the other hand, not only increases susceptibility to infections, but can even lead to mutations of viruses. With a deficiency, we are correspondingly more susceptible to infections and these can be more severe.

Selenium is important for the thyroid gland

The thyroid gland is a vital endocrine gland and plays a major role in metabolism. It is dependent on a number of micronutrients for the production of thyroid hormones, selenium is one of them, as it regulates the thyroid hormones. On the one hand, selenium ensures the conversion of the prohormone thyroxine (T4) into active triiodothyronine (T3); on the other hand, it deactivates triiodothyronine as required and converts it into inactive diiodothyronine. Selenium is also known to neutralize the free radicals that arise during hormone production. Selenium is also particularly important in Hashimoto’s thyroiditis. In this autoimmune disease, the immune system produces antibodies which are directed against the thyroid tissue and destroy it, resulting in hypothyroidism. With daily supplementation of 200 μg selenium, the antibodies can be significantly reduced.

Selenium deficiency

A selenium deficiency weakens the entire organism, with many possible consequences:

• Weakened immune system, susceptibility to infections
• White spots on fingernails
• Pale, dry skin
• Hair loss
• Muscle weakness (myopathies)
• Cardiomyopathy (weakness of the heart muscle)
• Coronary heart disease (CHD)
• Fertility problems in men
• Growth disorders
• Anemia
• Tiredness

A blatant selenium deficiency is often associated with an underlying disease that leads to poorer absorption or utilization of the trace element, for example:

• Chronic inflammatory bowel diseases
• Food intolerances
• Cystic fibrosis
• Renal insufficiency

Indications for selenium

• Selenium deficiency
• Thyroid diseases, especially Hashimoto’s thyroiditis
• Autoimmune diseases such as rheumatoid arthritis
• Asthma
• Chronic inflammatory (intestinal) diseases
• Strengthening the immune system
• Improvement of wound healing

Selenium overdose

Long-term overdoses with selenium-containing food supplements (from approx. 300 micrograms per day) can lead to neurological disorders, fatigue, joint pain, nausea and diarrhea, visual and memory disorders, skin damage, hair loss and impaired nail formation. Breath smelling of garlic is also characteristic. Selenium poisoning due to the intake of selenium in very high quantities (several grams) can lead to heart failure and death.

Suitable products

There are inorganic and organic selenium compounds, which differ mainly in terms of their availability in the body and the source from which they originate. The inorganic selenium compound selenite has the great advantage that the body can absorb it quickly and utilize it directly. Although the organic selenomethionine is absorbed very well, it is only available to the body with a time delay, as it is often incorporated into proteins. Another advantage of selenite is that the body can excrete it via the kidneys, which provides a certain degree of protection against overdosing. I recommend a product in liquid form, which tastes pleasantly of mango and can be conveniently dosed with a pipette. The selenium is contained in the form of sodium selenite and is optimally bioavailable.

Dosage

Depending on the clinical picture, 100 to 200 µg of selenium is appropriate.
Caution: Selenium should not be overdosed and should not be given to children.

Studies

Selenium for cancer prevention: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD005195.pub4/full

Biochemistry of selenium and its importance for human health: https://pubmed.ncbi.nlm.nih.gov/24185753/

Selenium for autoimmune diseases of the thyroid gland:https://www.thieme-connect.com/products/ejournals/abstract/10.1055/s-0033-1357118