Study · 2026 Edition
This page gathers what can be backed by numbers about one trace element: the process in testicular tissue, the element’s route to get there, measured levels in various foods, reference intakes from scientific societies, and the wording authorized on this topic in the European Union.
The formation of male germ cells is not a single event but a sequence that unfolds in a spatially ordered way within testicular tissue. Stem cells sit at the outer edge of the tubule; more advanced stages follow one another toward the lumen. A cross-section therefore shows all stages side by side — not because they start at the same time, but because each point in the tissue has its own starting moment.
Through ordinary cell division, a stem cell produces offspring, some of which remain in the tissue while others enter maturation division. In two successive steps, the chromosome set is then halved; one cell gives rise to four. Between these steps comes a phase in which the cell reshuffles its genetic material. Only afterward does the transformation begin that gives a round cell its characteristic slender shape.
During this transformation, the nucleus condenses: the usual packaging proteins are replaced by smaller, strongly basic proteins. The acrosome forms from vesicles of the Golgi apparatus and caps the nucleus. The tail grows from the centriole, mitochondria arrange themselves around its initial segment, and most of the cytoplasm is shed as a residual body, which is absorbed by the Sertoli cells.
In humans, the complete cycle, from the first division to release into the lumen, takes about two and a half months. This timeframe explains why, in studies, lifestyle changes only become noticeable after a clear delay — the cells released today were laid down several weeks ago.
Selenium does not reach the body as a free ion but in bound form. In plant foods, it is mostly present as an amino acid; in mineral preparations, as a salt. The two forms take different routes in the small intestine: the amino acid form follows the transport pathways of its sulfur-containing counterparts, while the salt form is absorbed through other channels. The absorbed fraction is high in both cases and, in studies, clearly exceeds half of the amount ingested.
After absorption, the element first travels to the liver. There it is incorporated into a transport protein that carries several selenium atoms and circulates in the blood. Target tissues take up this cargo through receptors on their surface. In testicular tissue, such a receptor is found on the Sertoli cells, which surround and nourish the maturing germ cells.
When intake is low, the body does not distribute the available element evenly but according to an order of priority. The brain, thyroid, and germ tissues are then supplied longer than the liver or muscles, where levels drop first. This order of priority has been described repeatedly in animals and is considered in the specialist literature an indication of which tissues depend on a steady supply.
No conclusions about specific individuals can be drawn from this observation. What can be stated is the wording of the Union list: Selenium contributes to normal spermatogenesis — In accordance with Regulation (EU) No 432/2012.
Selenium levels vary more than those of most other minerals, because the content of a plant food depends on the growing region and that of an animal food on the livestock’s feed. Tabulated values are therefore averages with a range, not fixed quantities. The table below shows rounded reference values per 100 grams of edible portion.
| Food | Selenium in µg |
|---|---|
| Brazil nuts | 1,000 to 5,000 |
| Cooked tuna | 70 to 90 |
| Herring | 40 to 45 |
| Lean pork | 10 to 15 |
| Chicken egg | 10 to 12 |
| Dried lentils | 8 to 12 |
| White button mushrooms | 7 to 18 |
| Wheat flour, type 1050 | 3 to 6 |
| Cow’s milk | 1 to 2 |
The range observed for Brazil nuts does not reflect measurement inaccuracy: it reflects differences between regions of origin. The same holds, on a smaller scale, for grains: in studies, North American batches show higher values than those from Central European farming.
On packaging, selenium content often appears as a percentage. The reference is a uniform labeling value of 55 micrograms per day, set by the consumer information regulation and identical for all adults. The estimates of the German-speaking scientific societies were established independently, differentiate by age and sex, and are higher for adult men. Two numbers for the same element therefore do not mean that one of them is wrong — they answer different questions.
| Group | Selenium in µg |
|---|---|
| Children aged 4 to under 7 | 20 |
| Children aged 7 to under 10 | 30 |
| Children aged 10 to under 13 | 45 |
| Adolescents aged 13 to under 15 | 60 |
| Men aged 15 and over | 70 |
| Women aged 15 and over | 60 |
| Breastfeeding women | 75 |
| Labeling value on packaging | 55 |
The European Food Safety Authority has also set a value of 70 micrograms per day for adults and sets the tolerable upper intake level for long-term intake at 300 micrograms per day. This limit applies to the sum of all sources, including what ordinary meals provide.
The following three statements appear in the Union list exactly as reproduced here. Each results from its own assessment and stands on its own.
In accordance with Regulation (EU) No 432/2012
In accordance with Regulation (EU) No 432/2012
In accordance with Regulation (EU) No 432/2012
These claims may not be merged, shortened, or reworded. The authorized text is the text, and the condition for its use is the presence of a minimum amount of the substance in the product.
Because the two were assessed separately and only formation resulted in an authorized wording. Each assessment concerns a specific relationship, backed by a specific body of data; if the review of another relationship is negative or was never requested, no entry is created. The absence of a claim implies neither the opposite nor an open question.
No. The wording refers to a physiological process, not a life situation. Authorized claims are addressed to the general population, without a medical diagnosis. Any question about a specific situation belongs in a doctor’s office — this page cannot and does not intend to replace that.
The register text mentions no age group. Use of the claim depends on a minimum amount in the product, not on the reader’s age. The intakes in the table above follow a different logic: they are graded by age and sex because they answer an entirely different question — the amount considered appropriate within a group.
The Union list contains other entries for selenium, notably on hair, nails, and the immune system. This page limits itself to the three wordings relevant to its subject and cites them in full. Making a selection is permitted; what would not be permitted is reproducing any of the entries in shortened or reworded form.
No. Laboratory parameters such as thyroid-stimulating hormone or the two thyroid hormones are measures that belong to medical diagnosis. The authorized claim, by contrast, describes a nutrient’s contribution to a normal function and says nothing about how a result changes in a given person.
The printed section picks up where this page leaves off: with the individual values. It expands the content table to more than sixty foods, details the calculation of four sample days in micrograms, compares the reference intakes of several bodies, and gives the source and year for every figure.
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