Selenium
What is selenium?
Selenium is one of the so-called trace elements, i.e., minerals that the body only needs in tiny amounts. But these small amounts are very important, because without selenium, many vital processes could not function properly. Even if we are not consciously aware of it, selenium is involved in our daily “functioning”: it supports enzymes that protect cells, strengthens the immune system, and ensures that our thyroid gland works reliably. Selenium can be thought of as an invisible but indispensable cog in a complex clockwork mechanism—small, almost inconspicuous, but if it is missing, the whole system falls out of sync.
What is selenium important for?
Selenium is best known for protecting our cells from oxidative stress. This means that it supports enzymes that neutralize free radicals, i.e., aggressive oxygen compounds that could otherwise attack our cells and accelerate the aging process (more on this topic in the Antioxidants guide). Selenium also plays an important role in maintaining a strong immune system and normal thyroid function. Skin, hair, and nails also benefit, as selenium is involved in growth and regeneration processes.
How much selenium do you need per day?
The recommended daily dose for adults is around 60 to 70 micrograms. At first glance, this sounds like very little, and indeed, the body only needs tiny amounts of it. But it is precisely these small doses that are crucial for vital processes to function smoothly.
Which foods contain high levels of selenium?
Brazil nuts are particularly rich in selenium. Just one nut can cover your daily requirement. Fish, meat, eggs, and milk also provide good amounts. Among plant sources, lentils, whole grains, and seeds are worth mentioning. However, there is one important point to note: the selenium content of plants depends heavily on how much selenium is in the soil. And our European soils are often rather poor in this trace element in comparison. This is because intensive agriculture and leaching over many centuries have caused some of the natural reserves to be lost. As a result, vegetables, grains, and legumes grown here usually contain less selenium than the same foods from other regions of the world, such as North or South America. This explains why it is often more difficult to get enough selenium in Europe, even if you eat a varied diet.
Foods rich in selenium:
- Brazil nuts
- Fish
- Meat
- Milk
- Lenses
- Whole grain products
- Seeds
What are the signs of selenium deficiency?
A slight selenium deficiency often manifests itself gradually. Typical signs can include brittle nails, hair loss, frequent infections, or a general decline in performance. In more severe cases, heart and muscle function can also suffer, or thyroid problems can arise. Anyone who suspects they may have a selenium deficiency should not treat it themselves, but should seek medical advice. A blood test can reliably show your selenium status. Only then can a decision be made as to whether targeted supplementation is necessary and, if so, in what dosage.
Brittle nails and hair
Nausea
Diarrhea
Garlicky breath
What are the signs of an overdose?
Even though selenium is important, you shouldn’t overdo it. Too much selenium over a long period of time, usually from high-dose supplements, can lead to nausea, diarrhea, brittle hair and nails, or even garlic-like bad breath. This smell occurs because the body converts excess selenium into so-called selenium compounds, which are excreted through the breath. In extreme cases, selenium can even be toxic. That is why it is important to keep an eye on the dosage.
Connection between selenium and zinc
Selenium and zinc often work hand in hand in the body. Both are involved in antioxidant processes and strengthen the immune system. While zinc is particularly important for activating enzymes and promoting wound healing, selenium protects cells from oxidative stress and supports the thyroid gland. So, making sure you get enough of both supports your immune system and lays a strong foundation for cell health and healthy aging.
How does selenium affect the thyroid gland?
The thyroid gland needs selenium to produce its hormones in the correct form. Together with other important nutrients such as iodine, iron, and zinc, selenium ensures that thyroid hormones can be produced and then converted into their active form. These hormones act as a kind of “clock” for the metabolism: they determine how much energy we consume, influence our weight, our body temperature, and even how focused and productive we feel. A lack of selenium can disrupt this process, causing the thyroid gland to work less efficiently and leading to symptoms such as fatigue, weight gain, listlessness, or increased sensitivity to cold.
