Selenium belongs to the group of minerals and is counted among the essential trace elements. It has a similar function in the human body as vitamin E: it is part of an enzyme that binds free radicals that are formed when fatty acids are damaged by oxygen. In addition, selenium is involved in the formation of the thyroid hormone. What foods contain selenium and how does it affect health?
Intake of selenium through food
Based on estimates, the German Nutrition Society recommends a daily intake of 60 µg for women and 70 µg for men – the WHO recommendations are slightly lower at 55 µg. This daily intake is contained, for example, in:
- 150 g herring or mackerel
- 120 g lentils
- 25 g Brazil nuts
- 150 g poultry meat
- 250 g potatoes
- 60 g Emmental
Good sources of selenium are animal and vegetable protein. Particularly rich in selenium are offal, meat and fish, cereals, nuts (especially Brazil nuts) and legumes, and porcini mushrooms. When buying, prefer products from organic farming – since they do not use fertilizers containing sulfur, they contain more selenium. In addition, it is recommended to consume food with a high content of vitamins A, C and E, as they improve the bioavailability of selenium in the body.
Fact sheet: selenium as a trace element
Named after the Greek moon goddess Selene because of its silvery-gray luster, this essential trace element was discovered in 1818 by the Swedish chemist Berzelius. The fact that it also occurs in the human body was not discovered until 1975. The amount of selenium in the body is about 10 to 15 mg; a large part of it is contained in the muscles, and also mainly in the liver, kidneys and heart. Selenium is absorbed in the upper parts of the small intestine and excreted mainly in the urine. Here’s what else you should know about selenium:
- Selenium is an essential trace element that must be absorbed through the diet.
- Rich in selenium is animal protein in pork, offal, fish, but also in nuts and porcini mushrooms.
- Selenium is important as a component of protective enzymes for the detoxification of the body.
- As an “antioxidant“, it fends off free radicals that are produced daily under the influence of environmental toxins, cigarettes and stress.
- Selenium administration could favorably affect the course of cardiovascular disease.
- Selenium is used as an adjunctive therapy for cancer, impaired immune defenses and acute and chronic infections.
- Selenium levels can be determined with a blood test.
Health significance of selenium
Selenium is a component of important enzymes and helps (in the form of the enzyme glutathione peroxidase) the body cells in the defense against aggressive metabolites, the so-called free radicals. In this function it belongs – like vitamins A, C and E – to the so-called antioxidants. The free oxygen radicals are produced during almost all metabolic processes and can damage the body’s cells and the genetic material (DNA) they contain, thus leading to cancer. In addition, selenium has an influence on male fertility, as certain building blocks of sperm production depend on it.
Does selenium protect against cancer?
It has been observed that in areas where a diet rich in selenium is prevalent, cancers and heart attacks are less frequent. Therefore, some protective effect against cancer and artherosclerosis (atherosclerosis) is also discussed. In experimental studies, selenium was shown to possibly prevent cancer. However, this effect is not considered scientifically proven and is controversial. In cancer patients, it has been found that an adequate supply of selenium improves the tolerability of anticancer drugs and the side effects of radiation therapy without impairing their effectiveness. Therefore, selenium administration is used for supportive treatment of many tumor diseases. In addition, international studies suggest that selenium may help inhibit tumor formation and growth in the skin, liver, prostate, and colon. In addition, selenium also protects the body from toxic heavy metal compounds (cadmium, lead, arsenic, mercury) and harmful radiation exposure such as UV light or radiation during cancer treatment.
Selenium for the thyroid gland
The thyroid gland is also affected by selenium, because the thyroid gland’s budget is regulated by enzymes that depend on the trace element. Studies suggest that in inflammatory thyroid diseases (Hashimoto’s thyroiditis, Graves’ disease), selenium supplementation may improve general well-being and some of the symptoms.
Defenses and immune system
Selenium also has a positive effect on the immune system. Selenium strengthens the body’s defenses – especially well when combined with zinc – and the additional administration can support the body in the event of blood poisoning or HIV disease. Patients with autoimmune diseases of the intestine, rheumatic diseases or allergic asthma can also be favorably influenced by selenium. Tip: During the infectious winter season, the body needs a particularly large amount of selenium. To meet this increased need, the trace element can also be taken as a dietary supplement, for example in the form of selenium yeast (available in pharmacies). If a cold is already on the way, the increased intake can even help to mitigate the symptoms of the disease and shorten its course.
