Selenium requirements: What should I bear in mind when taking a selenium supplement?

Food supplements are freely available: Whether in the drugstore or a click away in an online pharmacy, the pills, capsules or powders can be bought easily and conveniently. At the same time, there is a growing understanding in society that vitamins, trace elements and the like are important for health. Selenium is also one of these vital, so-called essential, substances that the body cannot produce itself. However, two things should be considered: Food supplements cannot compensate for a poor diet. And: An overdose of selenium can have fatal consequences.

Here is an overview of the most important facts about selenium as a dietary supplement:

- Background: What are dietary supplements actually good for?
- Selenium: Food supplements with antioxidant effects
- What is selenium important for?
- Preventing and correcting selenium deficiency
- Do you really need a selenium supplement?

Food supplements claim to supply people with vitamins, trace elements and other important substances that are not (sufficiently) absorbed through food. In principle, the need for these substances can be covered by a balanced diet. They are only really necessary in certain exceptional cases:

One-sided diet
- Illness/condition that results in an increased need for these substances.
- Disease/condition that impairs the absorption or utilisation of the substance.
- Industrially produced foods contain below-average amounts of trace elements/vitamins.

Selenium belongs to the substances that have a so-called antioxidant effect. Antioxidant substances take over a protective function in the body against the so-called free radicals. These are produced both in the body itself and by external influences such as UV radiation or environmental toxins. Free radicals damage the cells and  thus promote the development of diseases. In addition to selenium, there are other substances that have a similar function. These include  in particular vitamins A, E and beta-carotene. Since the media repeatedly propagate that these substances serve to prevent cancer and other life-threatening diseases, many people buy such food supplements. Studies show, however, that only in isolated cases can such food supplements actually make a positive contribution to health. Most of the time they are ineffective. And in cases of doubt, they can lead to health problems. This also applies to the dietary supplement selenium. Because in the case of an overdose of selenium, and this is actually almost only possible through the intake of selenium in the form of food supplements, poisoning occurs - the so-called selenosis. If left untreated, this can be fatal.

The trace element selenium plays an important role in several processes in the body. For example, it protects the body from harmful radicals as an antioxidant and is needed in the thyroid gland for the production of hormones. Furthermore, selenium ensures a good immune system, it strengthens the muscles and is responsible for the production of sperm cells.

You can prevent a selenium deficiency by eating a varied and healthy diet. If you are not sure whether your body has a sufficiently high selenium level, you can have a blood test done by your doctor, which can detect a deficiency. If the deficiency is confirmed, you may need to take a selenium supplement.

Selenium is found in many animal and plant foods. Therefore, the supply of selenium should primarily come from the diet. Only in exceptional cases is it advisable to cover the selenium requirement with dietary supplements. And then the following applies: The intake must be coordinated with a doctor and controlled by him.

Animal products with selenium content include meat, sausage, eggs, fish and seafood, but also dairy products. The most selenium-rich plant foods include nuts, especially Brazil nuts, asparagus, mushrooms, legumes, coconut, whole grains and cabbage.

Simply taking the remedy prophylactically is not a good idea. After all, an oversupply of selenium is just as harmful as a deficiency. Selenium has a toxic effect on the body in overdose. This means that too much selenium leads to poisoning, so-called selenosis.
It is therefore important to discuss the intake of selenium with your doctor. He or she can also advise you on whether it makes sense for you to take selenium in the form of food supplements.

In the following cases, you may not be able to meet your selenium needs from food alone:
- If you are a dialysis patient
- If you have an eating disorder
- If you have chronic diseases such as Chron's disease, pancreatic diseases and cystic fibrosis.
- If you drink too much alcohol
- If you have liver disease

Important: Even if a selenium deficiency is likely in these cases, it is important to refrain from self-medication. This is because the side effects of selenium can be particularly severe due to the previous illness, eating disorder or alcohol abuse.

Selenium is contained in numerous plant and animal foods. If you have a selenium deficiency, you can take selenium supplements. Although selenium supplements are available over the counter, you should always first check with your doctor whether you really have a selenium deficiency. This is because an overdose of selenium can lead to poisoning, known as selenosis.