Selenium: functions in the human body, foods rich in selenium
Jul 08, 2018
You, probably, often had to read about useful and necessary microelements for the body.One such substance is the chemical element Se( selenium).As an independent element, it was discovered only two centuries ago, and its need for the body was proved much later.Contents: Facts about selenium Functions of selenium in the body Factors leading to excess or lack of selenium Risk of selenium deficiency Acute selenium poisoning Chronic excess of selenium - a threat to health How to make up the deficit?
Facts about selenium
Here are some interesting facts from the difficult and unusual history of acquaintance with selenium and its role in the human body:
- As an independent element in 1817, J. Ya. Berzelius was discovered.
- Industrial application begins in the middle of the XIX century.
- The first photocells were made on the basis of selenium.
- From 1900 to 1950, the use of selenium was extremely limited due to its proven toxicity.
- 1954 marked the first scientific article about the positive biological properties of selenium.
- Since the 1950s, a study has been made of the effect of selenium on the human and animal organism.
- The content of selenium in the body is 10-15 milligrams.
- The daily human need is 70-100 micrograms.
- Selenium is part of a whole group of enzymes.
- Both the deficiency and the excess of selenium negatively affect the state of the body.
Functions of selenium in the body
Despite the content in the body in very small quantities, selenium is important for all cells, tissues and organs of man, as it performs many important functions.This is due to its occurrence in the composition of a number of enzymes, as well as the presence in the nucleus of each of the cells.In order to understand what happens with an overabundance, or a lack of selenium, it is first necessary to describe its physiological effects.
The physiological functions of selenium are:
- Protection of the body against biological threats.In the composition of special proteins, united in the group of selenoproteins, this element plays an important role in the regulation of the body's immune system.With its help an adequate response of the organism to the introduction of bacteria, fungi, viruses, and also the simplest microorganisms is carried out.
- Protection of the body against chemical hazards.Both in the process of functioning, and getting from the external environment, the body constantly has aggressive compounds that damage and destroy cells.Their action is resisted by a special, nonspecific system of antioxidant-antiradical protection, which includes a number of enzymes, biologically active substances and some other factors, including cellular ones.Selenium is an integral part of a significant number of compounds from this system.
- Participation in the metabolism of fats, proteins and carbohydrates.Selenium is necessary for the regulation of the normal synthesis of thyroid hormones, and also promotes the complete absorption of an element such as iodine from food and water.Mediately, through these and other biologically active compounds, selenium affects all kinds of metabolism in the body.
- Regulation of cell division.Selenium, like some other elements, is an indispensable factor for normal cell division.The presence of selenium in cells prevents mutations and the development of tumor cells, and in already existing cancer cells - it triggers mechanisms for their destruction.
- Anti-inflammatory effect.It consists in the regulation of chemical reactions and the actions of biologically active molecules, which are responsible for the course of the inflammatory-protective reaction.These substances are called mediators of inflammation, and selenium helps normalize their release.Particularly important is the role of this substance in the relief of conditions characterized by an excessive response of the body, such as bronchial asthma, arthritis, psoriasis and chronic forms of colitis.
- Detoxification properties.Selenium has the property of reliably binding and facilitating the rapid removal of heavy metal ions from the body: cadmium, mercury, lead, synthetic drugs, a number of toxic compounds of a biological nature - toxins of bacteria, fungi, protozoa.
- Cytoprotective action.Thanks to selenium, the aging and damage processes of both individual cells and the whole organism are significantly inhibited.That is why the presence of this element in the necessary quantities contributes to the maximum long-term functioning of cells of the central nervous system, heart muscle, liver and bone marrow.
- Reproductive effect.Selenium is metabolically very closely related to substances such as ascorbic acid( Vitami "C") and tocopherol( Vitamin E), biotin( Vitamin H).All these substances and, in the first place, selenium are extremely necessary for the normal functioning of the human sexual system.The action of selenium extends both to the synthesis of sex hormones and to the process of formation of sex cells.
- Other effects.Selenium plays an important role in the exchange of other chemical elements in the body.This applies to iron, copper, iodine, zinc and others, and this influence is mutually and interrelated.
Important: selenium is essential for the body, since it participates in almost all processes in the human body.By itself, it is quite toxic, so it is important that it is necessary to receive it in the body - within 70 - 100 micrograms per day.Deficiency of selenium in the body, just like its overabundance, leads to pronounced negative changes.
Factors leading to excess or deficiency of selenium
The main factors contributing to the deficiency of selenium in the body include:
- living in regions with a low content of selenium in the soil;
- diseases of the gastrointestinal tract with a violation of the absorption process;
- practiced vegetarianism, starvation, excessive diets;
- smoking and drinking alcohol;
- reception of some pharmacological preparations - oral contraceptives, laxatives, statins, adsorbents.
- advanced age;
- excessive consumption of selenium during pregnancy, chronic intoxication, for example, pollutants, in an unfavorable ecological setting;
A rare condition is the excessive intake of selenium into the body and is mainly associated with:
- features food with an abundance of products rich in selenium - mainly seafood;
- unreasonable or excessive intake of selenium medications;
- by random rapid intake of significant doses of selenium;
- chronic excess intake of selenium, for example, with a low level of safety in certain chemical industries.
Risk of selenium deficiency
With an abnormally low intake of selenium with water and food, a number of adverse events have been observed for a long time that can occur independently, mask for other diseases, or weight the picture already present.For the convenience of describing such states, we shall cite them in the same sequence in which the physiological effects of this element were expounded.
As a result of a lack of selenium, suffers:
- Immunity.Its protective properties are greatly weakened.And all components of the immune system are subject to negative influence - from leukocytes to antibodies.With prolonged and severe deficiency of selenium, conditions of almost complete immune deficiency can arise.This is manifested by the susceptibility of the body to infections of any type.Any infectious diseases are severe, with frequent complications, poorly amenable to medical correction.Recovery with a deficiency of selenium maximally stretched in time and rarely when it is complete.
- Antioxidant protection.Deficiency of selenium leads to rapid and massive damage to individual cells and rapid wear of tissues and organs.The patient has various types of dystrophy of the tissues, atherosclerotic and not only vessel changes.Rapid degeneration of the tissues of the central nervous system, bone marrow, muscle fibers.The result of selenium deficiency are various nonspecific diseases, and also that the most important weighting of the current of already existing diseases, such as ischemic heart disease, bronchial asthma, endocrine pathology and many others.This manifests itself in more frequent exacerbations, maximum manifestation of clinical manifestations, more difficult recovery and short duration of remissions.
- Exchange of substances.Disturbances are manifested in weighting the course of the existing endocrine disorders, as well as excessive or in contrast with insufficient weight, which is not actively corrected with the help of diets.Often there are violations of water and salt metabolism, the metabolism of other important macro- and microelements, which cascade leads to even more profound negative changes in the body.
- Normal cell division.This condition is one of the risk factors for the development of tumorous tumors, both malignant and benign.If there is a situation when selenium-deficiency conditions occur with already existing neoplasms in the body, this leads to a sharp increase in the growth and progression of tumors, the occurrence of relapses and the appearance of multiple metastases in malignant tumors.
- Anti-inflammatory function.Inflammatory reactions and processes associated with inflammatory mediators, such as bronchial asthma, allergic reactions of various types are more pronounced and difficult.They are much less amenable to drug correction in this case.
- Cell Protection.Protection of cells from biological toxins, organic and inorganic compounds, especially heavy metal ions, as well as toxic metabolic products of the body itself, decreases sharply, which manifests itself both in decreasing the general resistance of the organism and in the appearance of a variety of diseases.
- Reproductive function.She suffers from one of the very first, especially in men.This is not only in most cases the cause of male infertility, but also leads to a decrease in the intensity of desire and sexual activity.If the deficiency of selenium develops in women during pregnancy and this deficit remains without correction - this can lead to various pathologies of fetal development.In some cases, the catastrophic shortage of selenium causes spontaneous interruption of pregnancy and miscarriage.
Acute selenium poisoning
Please note! Selenium is a fairly toxic substance!
Acute intoxication with selenium is extremely rare and is observed when large doses of inorganic selenium enter the body at once, which is usually associated with accidental overdoses of drugs and technogenic causes - accidents in the production or processing of selenium.In this case, the clinical manifestations directly correlate with the amount of the dose that has entered the body.
Usually, the symptoms are manifested by common toxic effects.The patient is observed:
- abdominal pain and rapid chair;The gradual fading of this symptom is characteristic for several days;
- nausea is constant, vomiting, not bringing relief, but also uninvolved;
- sharp enough, pronounced garlicky smell from the mouth;
- severe headache, especially with movements, muscle pain;
- occasionally there may be photophobia and lacrimation in bright indoor lighting;
- weakness, increased fatigue, drowsiness without full sleep.
Carrying out general detoxification activities in intensive care units is enough to help the body to recover the field of acute selenium poisoning without any special consequences.
Important! There is no specific antidote for acute selenium poisoning.
Chronic excess of selenium - a health hazard
Chronic intoxication with selenium is not so common, and it is mainly related to living in regions containing excess selenium in soil, water and products.Also, chronic intoxication with selenium may occur in industrially undeveloped countries among employees of enterprises for the extraction or processing of selenium, when due to poverty no one cares about the safety and health of workers.
The main symptoms of chronic excess intake of selenium into the body are:
- Behavior change.Patients often have mood changes in the direction of depressive disorders, irritability, depression, increased fatigue.In addition, the intellectual component suffers, the overall efficiency decreases.A dream is broken, insomnia appears.
- Changes in skin and appendages.It consists in increased peeling of the skin, fragility and hair loss, the formation of abundant dandruff or seborrhea.In addition, nails change - they break and break off.There is an expansion of the capillaries of the skin, as a result of which the skin is hyperemic, as after burning in the sun.
- Indigestion.Mainly it is manifested by a decrease in appetite against a background of constant nausea, a slight odor of garlic from the mouth, spontaneous diarrhea, regardless of diet.
- . Oncological diseases.Despite the fact that selenium is necessary for normal cell division and protects the body from the appearance of tumor cells, its excess over a long time provokes the appearance of benign and malignant tumors.
Please note! The result of all of the above is the following conclusion.Both the excess and the lack of selenium in the body leads to the appearance of various pathologies or aggravates the course of already existing diseases.That is why it is necessary to ensure the intake of the strictly necessary dose of selenium.
How to make up the deficit?
Selenium has a remarkable feature - its disadvantage is simple enough to correct with the help of power.For this, it is necessary to add to the daily diet products rich in this element.
Three important features should be taken into account:
- When heat-treated, the amount of selenium is reduced on average by about half of the original level.
- Food rich in simple carbohydrates( sugars), alcohol, excessively fatty food reduces the level of assimilated selenium by almost 4 times.
- The average daily body requirement in selenium is 70 - 100 micrograms.
Below is a list of products containing selenium per 100 grams of raw product in descending order:
Note: is the champion in selenium content, it is bertholecium, or the Brazilian nut - one of its fetuses can cover the daily requirement of the organism in this element.A certain disadvantage may be the exotic nature and low prevalence of the product for ordinary Russians.
Our usual products containing selenium are:
- poultry meat( turkey, duck, chicken) 70-55 μg and animals( pork, lamb, beef) - 55-40 μg ,And in poultry meat selenium contains more;
- seafood( fish, shrimp, squid and more exotic lobsters, octopus, crabs) - 50-35 μg ;
- chicken eggs - 32 μg ;
- cereals and legumes - corn, rice, beans, lentils - 30-20 μg ;
- pistachios - 19 μg ;
- peas - 13 μg ;
- the usual nuts - peanuts, walnuts, hazel, almonds - 7-2.5 μg ;
- Vegetables and fruits - maximum to 2 mcg.
As you can see, a variety of food, even without special correction, can fill the body's needs for selenium.Moreover, it is very simple to calculate the number of necessary products.
The state of deficiency or excess of selenium can be established with suspicion of violations and confirmation by appropriate special biochemical analyzes.If the element is deficient, the diet is corrected and, in the case of a proven laboratory ineffectiveness of the diet, preparations containing selenium can be prescribed.
Important! Self-medication, independently taking selenium preparations without prescriptions or exceeding the dosage( in order to recover quickly) is extremely dangerous and is strictly prohibited .
For more information on the function of selenium in the body, the consequences of its excess and deficiency, you will get by watching this video review:
Therapist doctor, Sovinskaya Elena Nikolaevna