The simultaneous intake of inorganic selenium (sodium selenite) and vitamin C should be avoided since the optimal availability of sodium selenite can be affected hereby. The reason: Sodium selenite is converted by vitamin C into a form which is not available for the body. An intake with a time lag, of one hour e.g., does, however, not have an influence.
The mode of action of selenium from sodium selenite or sodium selenite pentahydrate is identical. In sodium selenite pentahydrate, only so-called water of crystallisation is integrated into the molecular structure. The information pentahydrate stands for five water molecules. Nevertheless, sodium selenite pentahydrate is a solid matter such as sodium selenite.
Free radicals are particles which incur in the body by the normal metabolism. Free radicals are highly reactive particles that can attack other cell components or tissue. The human organism has established protective systems which dispose of surplus free radicals in due time, before they can do so-called oxidative damage. These protective systems contain the trace element selenium. Therefore, selenium is significant for the protection of the cells from oxidative damage.
In case of sufficient selenium supply, the body produces so-called selenoenzymes which exert various functions. Selenoenzymes are protein compounds which have their activity as biocatalysts only with selenium as a component. They are as well called selenoproteins. So far, the selenium research has discovered about 25 selenoenzymes. The protection for cells and cell components from oxidative damage – i.e. antioxidant and anti-inflammatory functions – are their most important functions. Furthermore, selenoenzymes regulate the hormonal activity of the thyroid. The discovery of additional functions and further enzymes is still subject of the selenium research.
In the international comparison, rather low selenium levels are measured in Germany.
53-79 µg selenium per litre (whole blood)
[Deutsche Gesundheitshilfe, 2001, Selen - Ein lebenswichtiges Spurenelement, Sill-Steffens R; Kraus-Rauch, C.; Repp, V.]
Recommendation for ideal selenium levels in blood:
101-139 µg selenium per litre (serum)
121-168 µg selenium per litre (whole blood)
[Gröber U, Mikronährstoffe, Wissenschaftliche Verlagsgesellschaft Stuttgart, , 3. Auflage 2011] and [RKI, Selen in der Umweltmedizin, 2006] und [Deutsche Gesundheitshilfe, 2001, Selen - Ein lebenswichtiges Spurenelement, Sill-Steffens R; Kraus-Rauch, C.; Repp, V.]
Toxic selenium levels:
> 400 µg selenium per litre
[RKI, Selen in der Umweltmedizin, 2006]
The concern that by means of additional 200 µg selenium daily through a food supplement one is oversupplied, is not given as it is currently as well documented by the German Society for Nutrition . The EU has assigned a quantity of 55 µg selenium to a 100% value of the recommended daily dose for the labelling on the packagings in the EU . This selenium quantity is an estimated value for an average, healthy human in order to avoid a selenium deficiency state. According to the knowledge of experts and as well to latest information of the European Food Safety Authority (EFSA), this value is, however, too low in order to be able to build the necessary selenoenzymes in the body sufficiently . Unfortunately, there haven't been any officially valid new daily supply quantities, yet. According to the German Federal Environmental Agency, the optimum supply quantity of selenium for humans is 1-2 µg selenium per body weight . The maximum safe supply quantity, which can be taken in from all sources in the long term, is 300-400 µg selenium per day . Only from dosages 1,200 µg selenium daily and more, side effects could appear . Moreover, selenium from sodium selenite, as in Cefasel®/Cefasel nutri®, is not accumulated in the body. Should the body not need all selenium, it can be excreted again. Thus, the daily supply of 200 µg selenium is not too much, least of all if there is an undersupply via nutrition or if there is a larger demand of selenium.
 DGE. Ausgewählte Fragen und Antworten zu Selen: Deutsche Gesellschaft für Ernährung e.V. (DGE); 2015 [cited 2015 Mar 6].
 LMIV, Lebensmittelinformationsverordnung, VERORDNUNG (EU) Nr. 1169/2011 DES EUROPÄISCHEN PARLAMENTS UND DES RATES vom 25. Oktober 2011
 EFSA, Scientific Opinion on Dietary Reference Values for Selenium, EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA), EFSA Journal 2014; 12(10):3846
 nach Umweltbundesamt. Selen und Human-Biomitoring. Bundesgesundheitsblatt-Gesundheitsforschung-Gesundheitsschutz 45 2002) 2, 190-195
 (European Commission, SCF, SCF/CS/NUT/UPPLEV/25 Final, 2000 (IOM. Dietary Reference Intakes Elements, National Academies Press, 2000, www.iom.edu, www.nap.edu)
In principle, selenium can as well be measured in hair or nails because selenium is deposited there. Nevertheless, a selenium analysis from these samples shall be assessed as critical since hair and nails are not actively involved in the metabolic process. The use of partly aggressive hair care products or nail polish may falsify such analyses additionally. Therefore, a determination of selenium is carried out in the laboratories as a matter of routine only from blood samples.
Plants absorb selenium from the soil. Selenium reaches the meat through herbivorous animals,. However, since the soils in Germany contain little selenium, a vegetarian diet is rather insufficient for humans and animals for the selenium supply. Therefore, for the maintenance of health, selenium has been added to the feeding stuff of farm animals for decades. Hence, meat and innards, especially from chicken and pork, contain a relatively large amount of selenium.
Likewise, some fish species contain more selenium because selenium accumulates there through the food chain.
Indeed, Brazil nuts and coconuts come into question as vegetable selenium source. However, depending on the condition of the soil, the selenium content can be very high or as well very low.
Depending on the origin of the Brazil nut tree and the selenium content in the soil, the selenium quantities in the Brazil nuts fluctuate very much. According to bibliographical references, ca. 100 µg or just under 2,000 µg selenium can be contained in 100 g Brazil nuts. The range of measured values varies even between 3 and 51,200 µg selenium per 100 g fresh weight. Hence, it is not known if one should eat only a small piece or a handful Brazil nuts daily in order to take in 100 µg selenium. However, 100 g Brazil nuts supply as well on average 670 calories and just under 67 g fat. Brazil nuts take also a special position among the foodstuffs due to their exceptionally high radium contents. They can show up to 1,000 fold higher radium contents than the entire nutrition in Germany. Moreover, nuts are often contaminated by molds. Thus, Brazil nuts are not suitable for the specific selenium supply.
[Die große GU Nährwert Kalorien Tabelle, Elmadfa I, Aign W, Muskat E, Fritzsche D, Gräfe und Unzer Verlag, Ausgabe 2014/2015]
[BfR, verwendung_von_mineralstoffen_in_lebensmitteln_bfr_wissenschaft_4_2004.pdf, S266]
[Bundesamt für Strahlenschutz. Natürliche Radioaktivität in der Nahrung; Stand 21.04.2016]
[Fairweather-Tait S, Bao Y, Broadley M, Collings R, Ford D, Hesketh J et al. Selenium in Human Health and Disease. Antioxidants & redox signaling 2011:1337–83.]
The danger of an accumulation of selenium in the body does not exist for selenium as sodium selenite.
If too much selenium as sodium selenite had been taken in, the surplus selenium is excreted mainly via urine and stool but as well via the lung. Therefore, a garlic-like breath can be a reference to an oversupply with selenium.
An oversupply with selenium is very unlikely. According to individual case reports from literature, the following symptoms can appear but can degenerate again after stopping the selenium supply: garlic-like breath, exhaustion, tiredness, gastrointestinal complaints, hair loss, brittle hair, changes in nails (spotted, streaky, fragile), changes in skin.
[Ernährungsmedizin, Biesalski K, Bischoff SC, Puchstein C, Thieme-Verlag, 4. Auflage 2010]
Since selenium is involved in the maintenance of normal hair and nails, in the normal production of sperm and supports a normal function of the immune system and the thyroid, an undersupply with selenium can lead to functional disorders there.
An undersupply or a selenium deficiency can be proven by a measurement of the selenium level in blood.
Since the body cannot produce selenium, it is dependent on the daily supply. At best, this should be realised via foodstuffs containing sufficient selenium. If the supply via nutrition is not adequate, selenium can be taken in additionally every day. If a cure application is preferred, selenium can be taken in as well e.g. over 3 months daily as cure twice per year.
Studies show that in Germany and Europe the selenium supply on average is not sufficient in order get supplied sufficiently with selenium and to reach optimum selenium levels*. If the selenium deficits cannot be balanced via nutrition, a daily selenium supply, additionally to nutrition, is recommendable in order to supply the body with sufficient selenium. A blood examination can give an indication if the selenium supply is adequate.
[*Umweltbundesamt. Selen und Human-Biomitoring. Bundesgesundheitsblatt-Gesundheitsforschung-Gesundheitsschutz 45 (2002) 2, 190-195]