The vital trace element selenium is ingested from food. The FSVO regularly checks whether the population is supplied with sufficient selenium. The current monitoring focuses particularly on the supply to the population group with a vegan or vegetarian diet.
The importance of selenium for humans
Selenium is an essential trace element for humans and animals. As a building block for the amino acid selenocysteine, a constituent of many selenoproteins and enzymes, it plays a key role in numerous processes in the organism. Selenium, as a component of antioxidative enzymes, plays an important role, for example, in protecting the organism against radical-induced cell damage.
Other selenoproteins and enzymes contribute significantly to the regulation of thyroid hormones in the synthesis of the hereditary material DNA and in the reproductive system. Although a selenium deficiency occurs very rarely with normal diets it may result in an impaired immune system, dysfunctional muscle function and sperm formation. A correct selenium status also reduces the risk of cardiovascular diseases.
Selenium in foodstuffs
Foodstuffs represent the primary source of selenium; sufficient amounts must be ingested from food. Selenium occurs naturally in the soil, from there it reaches plants and through them attains animals and humans. Consequently, the amount of selenium in foodstuffs is strongly dependent on the selenium content of the soil and may vary considerably.
In Europe and in Switzerland the selenium contents of the soils are much poorer than in North America. Thus, the selenium contents in most vegetal foodstuffs of Swiss origin, such as cereals, are rather low. However, selenium is added to animal feed and consequently animal foodstuffs such as meat, eggs, milk and dairy products as well as fish are reliable sources of selenium. Mushrooms and certain vegetal foodstuffs, such as Brazil nuts, or to a certain extent cabbage vegetables, also represent valuable sources of selenium.
Observation system for the supply of selenium to the population
The FSVO monitors the supply of selenium to the population by means of periodic surveys. Recommendations to the population and health related measures can thus be adapted as needed. Studies in 1993 and 2005/2006 showed that the supply of selenium to the Swiss population was adequate at these times. However, since then, modifications to the flow of goods and new dietary habits could have affected the selenium consumption.
Consequently, the FSVO is currently carrying out a monitoring program in order to determine the selenium status of the adult population in Switzerland. The current monitoring focuses particularly on the selenium supply to the population group with a vegan or vegetarian diet. The intention is to determine whether this group runs the risk of an inadequate consumption of this trace element because meat and fish are the main sources of selenium in the diet.
Study design of the current monitoring program
In cooperation with Swiss Transfusion SRC and regional blood transfusion services in the cantons Neuchatel/Jura, Aargau/Solothurn, Zurich and Tessin, serum samples were collected from 700 blood donors. The samples were processed in the FSVO laboratories and the selenium content was determined by mass spectroscopy. A statistical analysis of these results of the representative samples can then enable conclusions to be drawn on the selenium consumption of the total adult population of Switzerland.
In a sub-project, blood samples will be taken from ca. 100 people with a vegan or vegetarian diet. These people will be recruited by the medical centre Unisanté Lausanne in the context of a pilot study for a national Swiss human biomonitoring project. The laboratories of the FSVO will carry out trace analyses for selenium in these blood samples. For further information on the pilot study: Human biomonitoring projects in Switzerland).
Timetable for this work
The samples from blood donors have already been collected and measured and the data are at present being evaluated. However, some delays have been encountered with people having a vegan or vegetarian diet. Due to the Covid-19 pandemic the recruitment of the participants has been suspended for the time being.
Therefore the conclusion for both sub-projects will probably not be made before the end of 2021. The FSVO will publish the results in the form of scientific publications and on the FSVO web site.
Last modification 31.05.2021
