selenium

Selenium is an important antioxidant and essential trace element involved in a variety of processes in the body.

As a component of over 25 selenium-dependent enzymes , the so-called selenoproteins, selenium plays an important role in vital processes. Among other things, selenium is important for protecting cells from oxidative stress, for thyroid function, for the normal function of the immune system, and also for sperm production in men.

Below you will learn what selenium is, how it works, which benefits have been scientifically studied, and for whom this trace element is important.

Selenium is a mineral and essential trace element, which means that the body cannot produce this mineral itself.

The body only needs a few micrograms of selenium per day, which is why it is classified as a trace element . However, this low requirement does not mean its effects are minimal. On the contrary, selenium primarily works through a special group of proteins called selenoproteins .

These proteins are special enzymes that help the body neutralize free radicals and pollutants.

These molecules are produced both during normal metabolism and by external factors such as sunlight or environmental pollutants. When these aggressive molecules are present in excess, they can attack cells and damage their structures.

To date , at least 25 selenoproteins have been identified. Among other things, they perform the following functions:

- Protection of cells from oxidative stress
- Regulation of thyroid metabolism
- Inflammation regulation and immune function
- Support of mitochondrial energy production
- Protection of DNA and cellular repair mechanisms

The importance of these proteins underlines the need for an adequate supply of selenium.

Many people in Europe consume less selenium than their bodies need in the long term.

The main reason lies not in the diet itself, but in the selenium-deficient soils of many European regions. Plants can only contain as much selenium as is present in the soil.

The concentration in plants and animals depends entirely on the selenium content of the soil .

Analyses of soil maps and nutrient profiles – for example from the European Soil Data Centre (ESDAC) – show that there is significantly less selenium in the soil in Central Europe compared to North America or parts of Asia.

That explains why:

a) People in some regions (e.g. USA) have sufficient selenium intake,

b) while others (e.g. Central Europe) traditionally have values ​​that are too low.

For this reason, selenium levels are rarely met through a purely plant-based diet, especially in Europe. Germany, in particular, is considered to be especially low in selenium.

Nevertheless, it is important to know which plant-based foods are natural sources of selenium:

Brazil nuts

Brazil nuts are often the best-known source of selenium, as 100g of Brazil nuts contain about 103 micrograms of selenium (and 683kcal), which is already more than the average daily requirement.

However, this is only an estimate, as the actual selenium content varies extremely. Depending on the region of origin, the value can range from very low to extremely high.

This makes them unsuitable for reliable dosing, but fundamentally a potentially very selenium-rich food.

eggs

Eggs regularly contribute to selenium intake, as the trace element passes from the chicken feed into the egg. The selenium content is therefore relatively constant at approximately 10 micrograms per 100g.

Mushrooms

Mushrooms are among the few plant-based foods that can naturally contain significant amounts of selenium, around 7 micrograms/100g.

However, their actual selenium content depends heavily on the substrate on which they grow. If the growing medium is enriched with selenium-containing minerals, mushrooms can reach comparatively high levels; in conventional cultivation, the content tends to be in the low to medium range.

Nevertheless, they regularly contribute to selenium intake – especially in Central European countries – and are considered an interesting, plant-based supplement to other selenium sources such as fish, eggs or whole grain products.

whole grain products

Grains absorb selenium directly from the soil. In regions with selenium-rich soils, whole grain products are a good daily source – however, in Europe, they are often significantly less so.

Animal occurrences

Since the animals' natural diet also contains too little selenium, this trace element has been added to animal feed for several decades. As a result, animal products in Germany – especially meat, fish, and eggs – now contain significantly more selenium than before and are among the more reliable sources in the diet.

Due to these properties of European soils, even a balanced diet often leads to a below-average selenium intake , without those affected consciously noticing.

Supporting cell protection

Selenium helps protect cells from oxidative stress .

Oxidative stress occurs when reactive oxygen species become excessive in the body – for example, due to metabolic stress, external influences, or stress. An adequate supply of selenium helps to better balance these stresses and maintain the long-term resilience of cells.

Health Claim: Selenium contributes to the protection of cells from oxidative stress.

Contribution to normal thyroid function

Selenium plays a crucial role in the normal functioning of the thyroid gland . The thyroid gland controls numerous processes in the body, including energy balance, metabolic activity, and temperature regulation. Adequate selenium intake helps ensure that these processes remain stable and balanced.

Health Claim: Selenium contributes to normal thyroid function.

Supporting a normal immune system

The immune system relies on a stable supply of micronutrients to react flexibly and effectively. Selenium contributes to maintaining the normal function of the immune system . Adequate selenium levels are often associated with a more robust immune system and a more balanced immune response.

Health Claim: Selenium contributes to the normal function of the immune system.

Maintaining normal hair and nails

In addition to its role in metabolism and the immune system, selenium also affects structures related to physical appearance. It contributes to maintaining normal hair and nails – particularly relevant in cases of stress, oxidative stress, or a poor diet.

Health Claim:

Selenium contributes to the maintenance of normal hair.
Selenium contributes to the maintenance of normal nails.

Contribution to normal sperm production

Selenium also plays an important role in male fertility. It supports the normal formation and development of sperm , affecting both their structure and function. Since sperm are particularly sensitive to oxidative stress, an adequate selenium intake is crucial for their quality and stability.

A balanced selenium level helps with this:

- to maintain the production of healthy sperm

- to protect the sensitive cell structures of the sperm

- to support normal mobility and function

Selenium is therefore one of the trace elements that are particularly relevant for male reproductive health.

Health Claim: Selenium contributes to normal sperm production.

Longevity research deals with the biological basis of aging - that is, the processes that determine how well the body repairs cells, produces energy, and responds to stress.

Selenium is repeatedly mentioned in this context because it is involved in several mechanisms that are among the so-called hallmarks of aging. belong.

The focus is on four major topics: cell aging, energy production, genetic stability and immune function in old age.

Protection against cell aging

As mentioned in the previous section, selenium plays a role in protecting cells against oxidative stress. Excessive oxidative stress is considered a major driver of cell aging.

Longevity research therefore considers selenium an important component of the body's own defense system. An adequate supply of selenium helps the body to better compensate for oxidative stress and to maintain the resilience of delicate cell structures.

Selenium thus indirectly contributes to the long-term maintenance of cell health – a core objective of longevity approaches.

Mitochondrial health

The efficiency of mitochondria, often referred to as the "powerhouses of the cells," declines with age. The resulting mitochondrial dysfunctions are among the best-known hallmarks of aging.

Selenium is frequently discussed in the context of longevity because it helps protect mitochondria from oxidative stress. This allows them to produce energy more efficiently and reduces so-called "metabolic stress".

Studies regularly associate improved mitochondrial function with higher vitality, improved resilience, and slower functional decline.

Telomere protection

Telomeres, often referred to as "protective caps of our chromosomes," shorten with each cell division. Their length is considered a marker for biological aging.

Some studies suggest that selenium may be associated with better telomere stability .

While research in this area is not yet fully completed, initial results show that adequate selenium intake may help support the structural integrity of telomeres - another factor that is being intensively studied in longevity studies.

Immune function in older people

The immune system changes significantly with age. This process often makes older people more susceptible to infections and inflammatory processes.

Research reveals a special characteristic of selenium: studies describe how adequate selenium levels can help support the immune system , particularly in old age. It is associated with improved function of certain immune cells and more stable inflammation regulation.

This could mean that selenium plays a role in mitigating typical age-related weaknesses of the immune system.

Although selenium is present in many foods, numerous nutritional analyses show that the supply in Europe is often below the optimal range, which is due to the selenium-poor soils.

Supplementation can be beneficial in many ways because it contributes to a balanced and reliable intake . Selenium's safety profile is well-researched, and the recommended amounts are much easier to achieve through supplementation than through varying food sources.

An addition may be particularly relevant:

- during periods of high physical or mental stress (e.g., intense exercise, stress), as the need can increase during such phases.

- in cases of low dietary variety , especially when little fish, eggs or whole grain products are consumed

- in cases of hypothyroidism , as the thyroid gland is one of the organs richest in selenium.

- as part of a longevity-oriented lifestyle , when the focus is on cell protection, energy balance and sustainable functionality

Supplementation is not a substitute for a balanced diet, but it can help to compensate for nutritional deficiencies and keep daily selenium intake stable.

Forms of selenium compared

Selenomethionine (organic form)

This form is similar to naturally occurring compounds in plant-based foods. It is very well absorbed by the body and stored in its reserves. Due to its high bioavailability, it is a commonly used form in high-quality supplements.

Advantages:

• very high absorption rate
• good storage capacity in the organism
• natural, food-grade form

Sodium selenite / sodium selenate (inorganic forms)

These forms are not stored, but are used directly in the body for physiological processes. They are particularly stable , considered well-researched, and characterized by a reliable, predictable effect.

Advantages:

• well-documented security profile
• Stable and quickly available
• Suitable for targeted applications

Selenium yeast

Selenium yeast contains a mixture of different selenium forms, predominantly organic. It is considered a "near-natural" variant because its composition is similar to that of selenium in whole grain products or plants.

Advantages:

• Mixture of different shapes
• natural composition
• moderate to high bioavailability

Which form is best?

- Selenomethionine → high bioavailability, suitable for long-term supply

- Sodium selenite/selenate → well documented, directly usable, stable form for precise dosing

- Selenium yeast → comes closest to food, however bioavailability varies

The overall dosage , the regularity of intake , and the high-quality manufacturing are important.

Selenium is one of the essential trace elements and is involved in numerous vital processes in the body.

Adequate selenium intake maintains the protection of cells from harmful influences, contributes to the normal function of the thyroid gland and immune system, helps maintain normal hair and nails, and plays a role in normal sperm production.

Furthermore, longevity research suggests that selenium is involved in mechanisms closely linked to healthy aging - from energy production in our mitochondria to the stability of our genetic information.

Selenium levels are particularly low in Europe due to selenium-poor soils, meaning that a balanced diet does not always reliably provide sufficient amounts.

That is precisely why selenium is increasingly viewed in modern health research as a dietary supplement that supports crucial functions in the long term.

Whether for general health maintenance, as part of an active lifestyle or in the context of a longevity-oriented approach: an adequate selenium intake is an essential component for keeping key bodily processes stable, efficient and resilient - and thus an important factor for well-being today and health tomorrow.