Continuing the series of articles on the role of micro and macro elements for runner health, Sergey Sorokin talks about such vital substances as iodine and selenium. To make the picture complete, you can read about zinc and iron and macronutrients .
Ongoing workout conditions encountered by runners cause the adrenal glands (adrenal glands) to work overtime to ensure metabolic needs. The thyroid gland produces tri-iodothyronine (T3), which facilitates the entry of nutrients into the cells and increases the production of energy within the mitochondria. This allows the body to meet energy needs. The thyroid and adrenal glands work together to neutralize the stress caused by constant training, infectious diseases, injuries, malnutrition, etc.
“Adrenaline fatigue” (reduced adrenal function) causes the thyroid gland to work with increased stress.Conversely, in the event of a malfunction of the thyroid, the adrenal glands are activated. For the normal functioning of the thyroid gland requires a sufficient amount of iodine and selenium (the basis of the formation of T3).
Iodine is a rare element on our planet, but is accumulated in large quantities by algae. For example, in the kelp concentration of iodine reaches 1%, which causes its high content in sea water. At the sea surface, iodides with evaporation rise into the atmosphere and are transferred by wind to the continents, where they precipitate. Due to the high volatility of iodine in coastal areas, up to half of the need for this trace element (150 µg / day) can enter the body through breathing, and as iraine is supplied with food, as it moves away from the sea. These circumstances cause a high iodine deficiency in the population in the center of large continents and in the highlands, where seafood is a rarity in the diet. Especially in Moscow.
The rate of iodine for athletes
It follows from the above that the need for iodine in athletes increases significantly, and the effects of iodine deficiency in this case are more dangerous and irreversible compared to iodine deficiency in ordinary, non-trained people. If an adult needs 100 micrograms of iodine per day, then in athletes the need increases to 200 micrograms.
To compensate for the iodine deficiency, its various sources are suitable: seafood (for example, seaweed), products artificially enriched with iodine (iodized edible salt), as well as preparations with organic and inorganic iodine compounds.
Iodine in foods
In this regard, it will be useful to know the list of products – iodine sources. Here the leading positions are occupied by seafood:
- sea kale – 300 mcg per 100 g of product;
- squid – 300 mcg per 100 g of the product;
- shrimp – 80 mcg per 100 g of product.
Sea fish is also considered a good source of iodine. Here is a list that shows the content of iodine per 100 g of product:
- hake – 160mkg;
- Pollock – 150 mcg;
- haddock – 150 mcg;
- cod – 135 mcg;
- capelin – 50 mcg;
- tuna – 50 mcg;
- pink salmon – 50 mcg;
- catfish – 50 mcg;
- Flounder – 50 mcg.
Slightly less iodine is found in river fish:
- perch – 60 mcg per 100 g of product;
- Som – 50 mcg per 100 g of the product.
The main leader of the energy metabolism of the cells of our body is the thyroid gland. It regulates the work of almost all human organs and systems and synthesizes a number of hormones for this regulation. Selenium is part of almost all enzymes and hormones. In all processes of formation of energy, immunity, hormones, selenium is present either as a substance or as an integral part of the enzymes involved in these actions.
Scientists estimate that about 200 enzymes contain selenium in their composition. Without it, these enzymes are simply not synthesized. Selenium is not – no enzyme. No enzyme – the hormone is not synthesized. A hormone is not synthesized – there is no energy in the cells. There is no energy in the cells – the thyroid gland “strains” and increases its size.
With the help of thyroid hormones and iodine, selenium skillfully controls our life, regulating immunity, metabolism, mental abilities and the quality of connective tissue.
Tissues and cells of our body are able to be built only from stable molecules. If the process of their oxidation starts, the process of tissue destruction starts accordingly. In order to restrain this process within certain limits, an antioxidant system exists in the body. These are vitamins A, E, C and trace element selenium. Selenium, as a peaceful warrior, is on guard to preserve the integrity of the cells. Only in the presence of selenium is synthesized GPO (glutathione peroxidase) – the main enzyme of antioxidant protection. That is why it is one of the most important trace elements for maintaining immunity and detoxification.
Selenium is an antagonist of mercury, arsenic, cadmium, it is able to protect the body from these elements; to a lesser extent, selenium protects against lead and thallium (in the latter case, vitamin E deficiency is of particular importance).
Selenium for the heart
Selenium not only protects our blood vessels from atherosclerosis, but also the heart muscle itself from the harmful effects of free radicals. Revealed a clear relationship between the level of selenium in the blood and the risk of coronary heart disease. In people with low selenium content, this “disease of civilization” is manifested 70 times more often!
Only in the presence of the optimal amount of selenium in our body is able to synthesize the important coenzyme Q10, which protects the heart muscle from oxygen deficiency and helps the heart muscle to recover from a heart attack. And all the runners know how important Q10 is for mitochondria to work.
Leading experts of our country understand the importance of selenium for human health. Here is what the General Director of the Cardiological Center of the Ministry of Health of Russia, Academician of the Russian Academy of Medical Sciences Ye.I. Chazov: “If the program of“ selenization ”of the population of Russia began to really work on a national scale, then in a year we could save 600,000 lives only of patients with cardiovascular diseases.”
Selenium in foods
Unfortunately, our body does not know how to synthesize selenium, and, therefore, it must come to us with food. The largest amount of selenium is found in Brazil nuts, garlic, onions. Well, if everything is clear with Brazil nuts, then regarding onions and garlic one should take into account the fact that the overwhelming majority of the territory of Russia is in the zone of natural deficiency of selenium in the soil. From this it follows that the plants grown on this soil do not contain enough of it. The widespread use of chemicals and fertilizers also reduces the level of this valuable trace element in the soil and in plant products, and even translates it into indigestible form.
Bad eating habits – the abuse of sweet foods, carbonated drinks – reduce the level of selenium in the body, as it is not absorbed in the presence of simple carbohydrates. Cereals lose about 70% selenium during the purification process. Selenium is contained in sufficient quantities in seafood and some meats, however, when cooked, its level is significantly reduced to 50%.
A deficiency of selenium in the body also occurs when taking fairly common medicines, for example, paracetamol, phenacetin, antimalarial drugs, sulfates.
Here are the champions in the content of selenium (per 100 g of product):
- mushrooms – 100-110 mcg;
- coconut – 80 mcg;
- seafood – 52 mcg;
- Brazil nut – 50 mcg;
- beef – 31 mcg;
- bacon – 30 mcg;
- cottage cheese – 30 mcg;
- beans – 25 mcg;
- garlic – 20-40 mcg;
- chicken fillet – 21 mcg;
- chicken eggs – 15 mcg;
- spinach – 11 mcg.
Norma selenium for athletes
The daily need for selenium according to who is 80-200 mcg. This is a very small dose. Subject to the daily intake of such an amount, for the whole life the total volume will not exceed half a teaspoon! And even this small amount, unfortunately, is very difficult to get with modern food. According to Russian epidemiologists, at present, about 80% of the country’s population suffers from selenium deficiency. It is estimated that, on average, a resident of Russia consumes only 25-30 μg of selenium per day with food.
Athletes in the period of serious stress need up to 200 micrograms of selenium. The main problem of lack of selenium is the predominance of refined food in the diet. Selenium, like most trace elements, is just in the shell of the grain. That is, the refined flour of the highest grade does not contain selenium, and in bran it is present in the amount of 12 micrograms per 100 grams.
In other words, regular nutrition based on refined products gradually leads to a lack of trace elements.And this can greatly affect the training process and overall health.