E-Mail: info@behrbonn.com
Dr. Behr GmbH
Königswinterer Str. 37 a - D-53227 Bonn
Tel. +49-228-976396-0 - +49-228-976396-12
Dietetic and Pharmaceutical Raw Materials
THE PHYSIOLOGOCAL ROLE OF THE TRACE ELEMENT SELENIUM
Selenium is an element
which is in traces essential for the human nutrition. Its essentiality is
explained by its occurrence in various human enzymes, e.g. in four different
gutathione peroxidases which act together with glutathione in the reduction of
H2O2 (and prevents thus indirectly the formation of hydroxyl radicals via the
Fenton reaction) and of lipid peroxides (FLOHE, 1971, HOEKSTRA, 1975; CHU,
1993). The pospholipid hydroxide glutathione peroxidase is the only enzyme
capable of reduction of peroxidized fatty acids in membrane phospholipids into
alcohols (KUKLINSKI, 1991). More recently Selenium was found in the
I-Iodinethyronine deiodase (BEHNE, 1990; BERRY, 1991). In the plasma protein
selenoprotein P (of still unknown function) seven to eight selenocysteines
exist per polypeptide chain (BURK, 1991). Selenoprotein P accounts for two
thirds of the Selenium present in the serum.
It is known that a too low
supply of Selenium leads to an increased risk of atherosclerosis (KIEM, 1982)
and cancer (SHAMBERGER, 1971; SCHRAUZER, 1977; BURNEY, 1989; HELZLSOUER, 1989).
Selenium does also play a role in the detoxification of the heavy metals
cadmium and mercury (PARIZEK, 1971; GASIEWICZ, 1976), in the function of the
immune system (BERENSHTEIN, 1972) and probably also in the biosynthesis of
cartilege (MÜLLER, 1991). Acute pancreatitis, an often lethal disease, is also
caused by selenium deficiency. After administration of selenium dramatic
recoveries have been observed (KUKLINSKI, 1991). SEO (2002) explains the cancer
chemopreventive effect of Selenium by a redox mechanism in which
Selenomethionin activates the p53 tumor suppressor protein.
The daily requirement of
selenium has been determined by LEVANDER and MORRIS (1984) by an equilibrium
regression study to be 80 mcg for adult males and 57 mcg for females. The
German Society for Nutrition recommends the following values as an adequate
intake of selenium (DEG, 1991):
Babies mcg/day
0 to 4 months 5-15
4 to 12 months 5-30
Infants
4-7 years 15-70
7 to 10 years 15-80
above 10 years 20-100
Adults and adolsescents
20-100
A too high intake of
Selenium has a toxic effect. According to COMBS (1986) the upper safe limit is
775 mcg (organically bound) selenium per adult person and day for a long term
consumption. The limit for inorganic selenium is 550 mcg per person and day.
According to various authors the selenium supply in many European countries is
suboptimal (ROEKENS, 1986; BRÜGGEMANN, 1989). The investigation of BRUEGGEMANN
(1989) showed that the daily consumption of 250 g of bread from grains
harvested in
References
BEHNE, D., et al., 1990:
Identification of Type I Iodothyronine 5'-Deiodinase as a Selenoenzyme.
Biochem. and Biophys. Res. Comm., Vol. 173, No. 3, 1143-1149, 31.12.90
BERENSHTEIN T.F., 1972: Effect of selenium and vitamin E on antibody formation in rabbits, Zdra Wookhr. Beloruss., 18, 34 BRÜGGEMANN, J. et al., 1989: 40. Tagung für Getreidechemie in Detmold, 8.-9.6.1989
BURK, R.F., 1991: Molecular
biology of selenium with implications for its metabolism. FASEB Journal, vol 5,
June 1991, 2274-2279
BURNEY, P.G. et al., 1989:
Serologic precursors of cancer: serum micronutrients and the subsequent risk of
pancreatic cancer. Am-J-Clin-Nutr. 1989 May; 49(5): 895-900
COMBS, G.F.; COMBS, St.B.,
1986: The role of Selenium in Nutrition, Academic Press 1986, S. 511
DEG, 1991: Deutsche Gesellschaft für Ernährung. Empfehlungen für die Nährstoffzufuhr. S. 75
FLOHÉ, L., 1971: Die Glutathionperoxidase: Enzymologie und biologische
Aspekte. Klinische Wochenschrift, 49. Jg., Heft 12, 15. Juni 1971
GASIEWICZ, T.A.; SMITH
J.C., 1976: Interactions of cadmium and selenium in rat plasma in vivo and in
vitro. Biochim. Biophys. Acta, 428, 113, 1976
HELZLSOUER, K.J. et al.,
1989: Selenium, lycopene, alpha-tocopherol, beta-carotene, retinol, and
subsequent bladder cancer. Cancer Res. 1989 Nov 1; 49(21): 6144-8
HOEKSTRA, W.G., 1975:
Biochemical function of selenium and its relation to vitamin E. Federation
Proceedings Vol. 34, No. 11, October 1975, 2083-2089
KIEM, J.; FEINENDEGEN, L.E., 1982: Die Beurteilung von Spurenelementen in
Nahrungsketten, AGF Veranstaltung Bonn, 4.-5.11.82 KUKLINSKI, B., 1991: Akute
Pankreatitis - eine "free radical desease". Letalitätssenkung durch
Natriumselenit-Therapie. Z. gesamte Inn. Med. 46 (1991) 5, 145-49
LEVANDER O.E.; MORRIS, V.C., 1984: Dietary selenium levels needed to maintain balance in North American adults consuming self-selected diets. The American Journal of Clinical Nutrition 39: May 1984, pp 809-815
MÜLLER, P., 1991: Materie und Prozesse, Tagungsbericht der Deutschen Gesellschaft für Naturforscher und Ärzte, WVA, Stuttgart, S. 251 (W. Gerok ed.)
PARIZEK J. et al., 1971:
The detoxifying effects of Selenium, in: Mertz, W. & Cornatzer, W.E., ed.,
Newer trace elements in nutrition, New York, Marcel Dekker, Inc., p. 85-122
ROEKENS E. J. et al., 1986:
Dietary selenium intake in
SEO, Y. R.. et al., 2002: Selenomethionin regulation of p53 by a
ref1-dependent redox mechanism. Proc. Natl. Acad. Sci.USA, Vol 99, Issue
22, 14548-14553, October 29, 2002
<hr
