selen

Selenium (Se) is one of the most important bioelements, necessary for the proper functioning of the body. The content of selenium in the organism of an adult man varies between 10 – 30mg. It occurs in whole human organism and the largest amount is found in the liver and muscles (about 30% of the total selenium pot in the body). In addition, significant quantities of this element are found in kidneys (about 15%), blood plasma (about 10%) and in the prostate and semen.

Organism daily requirement for this element is 150-200 µg. It increases during pregnancy and while breastfeeding. In turn, the correct concentration of selenium in blood serum, should be within 100 to 200 µg/l. Due to the low content of selenium in foods, supplementation is necessary.

It is believed that deficiency of selenium in the body is observed when its concentration in blood serum is less than 85 µg/l. It is due to limited bioavailability of mercury in foods and improper diet. The most common effects of selenium deficiency are:

  • enlargement of the heart muscle,
  • heart arrhythmias,
  • cardiovascular failure,
  • increased risk of having a heart attack,
  • reduced efficiency of the immune system,
  • articular cartilage dystrophy,
  • higher risk of cancer (in men- prostate cancer, in women- breast cancer),
  • increased risk of diabetes or stroke,
  • hypothyroidism,
  • depression, anxiety, fears.

The main functions of selenium, carried out in the human body are:

  • its contribution to the transmission of nerve impulses in the central nervous system,
  • binding and neutralizing toxins and heavy metals,
  • neutralizing reactive oxygen species, by increasing the activity of glutathione peroxidase,
  • impact on the correct metabolism of thyroid hormones (selenium is a part of enzyme responsible for the conversion of the inactive thyroxine- t4 into active thyroid hormone- triiodothyronine- t3),
  • to stimulate the immune system to produce antibodies,
  • anticancer activity, by preventing the proliferation and growth of cancer cells,
  • prevention of vascular diseases of the heart,
  • anti-inflammatory and antiviral activity,
  • together with vitamin e retards the aging process.

Selenium can be extracted from food both in the form of inorganic compounds (selenites, selenates) and organic (selenocysteines, selenomethionines). The absorption of this microelement takes place in the small intestine. To all tissues of the body it is delivered by personified elements of the blood- erythrocytes as well as blood plasma. The amount of absorbed selenium equals 85 to 95% of the pot of that element supplied in the diet. Selenium’s best absorption is in he form of organic compounds. Its bioavailability is greater in the case of food products of animal origin than vegetable. Favorable factor in its absorption is diet rich in vitamins A and E and low molecular weight proteins. However the sulphur compounds contained in food and vitamin C can help the reduction of the intensity of the absorption process of this microelement.

Due to the low concentration of selenium in the blood plasma of most people, it is recommended that the intake of that element should be in form of dietary supplements. Supplement of choice is selenium built to bakery yeast. When choosing the right product please note that preparation of selenium enriched was one of the vitamins A or E.

Sources:

  • Fitak E., Wagner L. 2009. Selen – rola biologiczna, znaczenie w medycynie i stomatologii na podstawie piśmiennictwa. Nowa stomatologia 3: 82 – 84.
  • Floriańczyk B. 1999. Selen i selenoproteiny w zdrowiu i w chorobie. Nowiny Lekarskie
    68 (2): 244 – 253.
  • Kuczyńska J., Biziuk M. 2007. Biogeochemia selenu i jego monitoring w materiałach biologicznych pochodzenia ludzkiego. Ecological chemistry and Engineering 14: 47-49.
  • Wojtasik A., Jarosz M., Stoś K. 2012. Składniki mineralne, [w]: Normy żywienia dla populacji polskiej – nowelizacja. Instytut Żywności i Żywienia, Warszawa.
  • Zwolak I., Zaporowska H. 2005. Rola selenu oraz wybranych Se-białek w organizmie człowieka. Annales 16: 457 – 460.