Selenium - a vital trace element
It was not until 1975 that selenium was found in the human body. Selenium is part of an enzyme that can bind free radicals that can be produced by environmental toxins, cigarettes, and stress. It has a similar function to vitamin E and is also involved in the formation of thyroid hormone.
In the body of an adult, about 10 to 15 milligrams of selenium are stored, most of it in the kidneys, but also in the liver, heart, brain and blood. In contrast, bones, muscles and fatty tissue contain only a small amount of selenium. It is taken in the small intestine and excreted in the urine.
The need for selenium
The daily selenium requirement of an adult human is about 0.03 to 0.07 milligrams. This should be covered by a balanced diet.
Selenium is mainly found in plant foods. However, the selenium content of plants depends on the selenium content of the soil on which they grow. Germany is in a good midfield, but the soils in Asia and Africa are very low in selenium, while z. For example, the North American soils are selenosaturated.
Because of these large differences in the selenium content of soils, of course, the selenium content in the crops also varies. The fact that our soils do not contain so much selenium is due, among other things, to acid rain and to the use of sulfur-containing fertilizers, because it absorbs sulfur from the plants instead of selenium. Therefore, the trace element selenium is often added to the cattle feed; and, moreover, the animals are also less susceptible to disease. For this reason, animal foods such as meat, fish and eggs can usually even be better sources of selenium than vegetable foods.
Selenium-containing foods
Whole grain cereals and vegetables, especially cabbage vegetables such as red cabbage and white cabbage, but also broccoli, onions, garlic, mushrooms, asparagus, peas, lentils, coconuts, sesame, millet and ginseng roots have a high selenium content. Brazil nuts contain a lot of selenium, even 6-8 pieces cover the daily needs of an adult.
Of the animal foods, beef, veal and chicken, and especially game meat, egg yolk, liver, cheese, herring, redfish, trout, lobster and tuna, contain relatively high levels of selenium.
Here are a few examples of the amount of some foods that can reach the required daily dose of an adult (about 0.03 to 0.07 mg):
- 350 g of meat
- 90 g liver
- 120 g of lenses
- 200 grams of salmon
- 150 g Bismarck herring
- 10 g trout
- 45 g tuna
- 25 g Brazil nuts
The lack of selenium and the consequences
- Selenium deficiency is very rare in Europe. The consequences of selenium deficiency have not yet been fully explored. In areas with extreme selenium deficiency such as In China and Central Russia, for example, the most severe myocardial and joint diseases were observed. However, it is still unclear whether these diseases are actually the result of selenium deficiency or other causes.
- But there are studies that suggest a link between low levels of selenium and lipid metabolism disorders, high blood pressure, thyroid inflammation and the emergence of arteriosclerosis.
- Similarly, selenium deficiency may also affect fertility: women who have suffered from miscarriages have had extremely low blood levels of the trace element, and in males with selenium deficiency, sperm maturation and motility may be disturbed.
- Selenium deficiency can also arise as a result of chronic diseases such as cystic fibrosis, renal insufficiency or inflammatory bowel disease. Also, people who are very one-sided or vegan or suffer from eating disorders, older people with one-sided or inadequate nutrition, alcoholics, patients with tube feeding and dialysis patients are at higher risk for selenium deficiency.
- In addition, a selenium deficiency can also arise when selenium is excreted in long-lasting diarrhea, or even in the urine in diabetes or severe kidney disease. Also gastrointestinal diseases can lead to a disturbed selenium intake. There may also be an increased need for selenium during pregnancy, lactation and heavy menstrual bleeding. Even with cancer, the body consumes more selenium.
- Since selenium is an important building block for neurotransmitters (such as serotonin), it can often lead to anxiety, dissatisfaction and depression in people who have very low levels of selenium.
The overdose of selenium and the consequences
Selenium in a higher concentration has a toxic effect. The body then usually excretes excess selenium with the urine, but if you regularly take larger amounts of selenium (for example, through dietary supplements) over a longer period, this can lead to complaints such as liver damage, nerve disorders, joint changes (such. B.Osteoarthritis / arthritis), hair loss, myocardial insufficiency or reduced bone growth.
