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Selenium benefits: An essential trace element

photo de sélénium oligo-element en complément alimentaire, gélules blanches
Although present in tiny amounts in the body, selenium plays a fundamental role in the body. This micronutrient is involved in key functions such as immunity, male fertility, protection against oxidative stress and thyroid function.

Essential but sometimes overlooked, its intake largely depends on diet... and on the selenium content of agricultural soils, which varies greatly from region to region. This can influence the needs of certain populations such as athletes, vegetarians or people following a restrictive diet.

In this article, discover the key benefits of selenium, its best food sources and why this micronutrient deserves a prominent place in your nutritional balance.

What is Selenium?

1. An essential trace element

Selenium is an essential trace element, meaning it's a mineral the body needs in very small amounts, but whose functions are vital for the organism. Present in every cell, it is found in higher concentrations in the thyroid gland, kidneys, liver, and muscles.

Since the body does not produce selenium, its intake depends exclusively on diet or supplementation.

2. The history of selenium: from its discovery to its worldwide use

Selenium was discovered in 1817 by the Swedish chemist Jöns Jacob Berzelius. Initially, selenium was primarily considered a toxic industrial waste product; it was only in the 20th century that its biological properties began to be better understood.

  • From presumed toxicity to an essential micronutrient

It was only from the 1950s and 1960s that selenium was progressively recognized as an essential micronutrient, for both humans and animals. A major breakthrough occurred in 1973 when researchers demonstrated its active role in the body through an enzyme: glutathione peroxidase. This discovery marked a turning point in the understanding of selenium, which was now recognized as a key element of human physiology.

  • A trace element now recognized worldwide

Currently, selenium is included in official nutritional recommendations in many countries. It is used in:

- Human nutrition, particularly through food supplements or the enrichment of certain products,
- Animal nutrition,
- And various clinical studies, exploring its effects on immunity and other bodily functions.

The recommended daily allowance (RDA) for selenium varies by country and public health authorities. In France, Anses (the French Agency for Food, Environmental and Occupational Health & Safety) recommends an intake of 70 micrograms per day (µg/day) for an adult. Appropriate intakes, neither excessive nor insufficient, are essential to fully benefit from this micronutrient.

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Selenium in food: where to find it?

Selenium is naturally present in a variety of foods, mainly of animal or plant origin, such as:

  • Brazil nuts, very rich in selenium,
  • Fish (tuna, sardines, mackerel),
  • Seafood (shrimp, oysters),
  • Meats, eggs, and dairy products,
  • Whole grains (oat flakes, brown rice, quinoa)

The selenium content of plant-based foods depends heavily on the quality of the soil in which they were grown. In some regions, particularly in Europe, soils can be naturally poor in selenium, which reduces the amount absorbed by crops.

When to consider supplementation?

Certain dietary habits (vegetarian or vegan diets), an industrialized diet poor in nutrients, or significant needs (in athletes, for example), can limit selenium intake.

In these cases, supplementation may be considered, but it should always be done thoughtfully and under medical advice. Indeed, an excess of selenium can have undesirable effects, hence the importance of finding the right balance according to individual needs.

Selenium benefits: numerous functions in the body

1. Selenium: essential support

Present in very small quantities but widely distributed in the body, selenium is found in high concentrations in the thyroid gland, liver, kidneys, muscles, and in the testicles in men. It is primarily active in the form of selenoproteins, proteins that perform major biological functions.

This micronutrient plays a key role in the proper functioning of the body. It contributes notably to:

  • Normal immune system function,
  • Normal spermatogenesis,
  • Normal thyroid function,
  • The protection of cells against oxidative stress,

And it also participates in:

  • The maintenance of normal hair,
  • The maintenance of normal nails.

2. Selenium and zinc: a beneficial synergy

Zinc, another essential trace element, is present in many body tissues, particularly in the skin, hair, bones, pancreas, prostate, and white blood cells. It also participates in several fundamental processes.

Zinc and selenium have many common benefits:

  • Normal immune system function,
  • Protecting cells against oxidative stress,
  • Maintenance of normal hair,
  • Maintenance of normal nails.

Zinc also distinguishes itself by its involvement in male hormonal balance, by contributing to the maintenance of normal testosterone levels in the blood.

The combination of selenium and zinc therefore helps to participate in complementary mechanisms, especially during particular periods.

Selenium benefits: in summary

Small in quantity but great in its effects, selenium is a key trace element for the proper functioning of the body. It participates in immunity, protects cells from oxidative stress, contributes to thyroid function, male fertility, and helps maintain hair and nails.

Associated with other nutrients like zinc, another mineral, they act in synergy in the body thanks to their numerous benefits.

An adequate intake, mainly through diet or supplementation, allows one to fully benefit from its many daily advantages.

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