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Hygienic importance of minerals and vitamins in the diet of the population
Minerals and vitamins play a very important and at the same time peculiar role in the vital activity of the organism. First of all, they are not used as energy materials, which is a specific feature for proteins, fats and carbohydrates. Another distinctive feature of these nutrients is the relatively very insignificant quantitative need for them in the body. Suffice it to say that the daily intake of all mineral elements and their compounds does not exceed 20-25 g, and the corresponding figure for vitamins is expressed even in milligrams.
As already mentioned, mineral substances are vital components of nutrition, ensuring the development and normal functional state of the body. According to their content in food products, they are conventionally divided into two groups. The first includes the so-called macronutrients contained in relatively large quantities (calcium, phosphorus, magnesium, potassium, sulfur, chlorine, etc.). The second includes trace elements found in products in small quantities (iron, cobalt, manganese, iodine, fluorine, zinc, strontium, etc.). Some researchers also distinguish a group of ultramicroelements, the concentration of which corresponds to gamma percentages (gold, lead, mercury, radium, etc.).
It can be considered established that the participation of mineral substances along with other components of food in all biochemical processes occurring in the body. It is also proven that these substances have pronounced activity and can be considered true bio-elements. At the same time, being in the blood plasma and other body fluids, they are of great importance in the regulation of the main vital functions. This is due to their influence on the state of colloids of tissues, which determine the degree of dispersion, hydration and solubility of intracellular and extracellular proteins.
At the same time, a sufficiently high and stable content of some macroelements contributes to maintaining the saline composition of blood and osmotic pressure at a constant level, on which the amount of water retained in the tissues largely depends. So, sodium ions enhance the ability of tissue proteins to bind water, and reduce potassium and calcium ions. As a result, an excess of table salt will ultimately hamper the activity of the heart and kidneys and adversely affect the status of the respective categories of patients.
A very important role is played by mineral substances for the formation of buffer systems of the body and maintaining its acid-base state at the proper level. At the same time, the prevalence of potassium, sodium, magnesium and calcium in food products causes their alkaline orientation, and sulfur, phosphorus and chlorine - acid. In the usual mixed diet food rations are often characterized by a high content of acidic substances, which can lead to the occurrence of acidosis.
The established value is the trace elements for the endocrine apparatus, the activity of hormones and enzymatic processes. This is evidenced by the participation of iodine in the activity of the thyroid gland, the effect of copper and cobalt ”And the action of adrenaline, zinc and cadmium — insulin, etc.
A large physiological role is played by mineral substances in plastic processes, in the construction and formation of body tissues, especially the skeleton. In this regard, the importance of calcium, phosphorus, magnesium, strontium and fluorine is well known, and their inadequate intake with food inevitably leads to impaired growth and calcification of bones.
The existence of biogeochemical provinces, that is, areas where the number of certain trace elements in the soil has been dramatically increased or decreased, indicates the biological activity of the mineral components of nutrition, which affects the composition of the plants growing on it, the composition of water, milk and animal meat. If people live in such areas for a long time, then this may entail the development of peculiar pathological conditions, such as endemic goiter or fluorosis.
When characterizing individual microelements, it is necessary, first of all, to focus on the physiological role of calcium, the compounds of which significantly affect the metabolism, cell growth and activity, the excitability of the nervous system and muscle contractility. It is particularly important in the formation of skeletal bones as one of the main structural components. However, only at a certain ratio in the blood of phosphorus and calcium, the deposition of the latter in the bone tissue proceeds normally. If the number of these elements is not balanced, then there is a violation of the processes of ossification, expressed in the occurrence of rickets in children, osteoporosis and other bone changes in adults. It was established that their optimal ratio is 1: 1.5 - 1: 2. Due to the fact that in the diet, this ratio is usually far from optimal, then for the normalization of the relevant processes, the regulating role of vitamin O, which promotes the absorption of calcium and its retention in the body, is necessary. It should also be noted that it is very difficult to assimilate the macro element due to the extremely low solubility in water. Only the action of bile acids, accompanied by the formation of complex compounds, allows us to transfer calcium to an assimilable state.
The content of phosphates in food is very important for the body, since organic phosphorus compounds are genuine energy accumulators (adenosine triphosphate, phosphoryl cretinine). It is these compounds that are used by the body during muscle contraction and biochemical processes occurring in the brain, liver, kidneys and other organs. At the same time, phosphoric acid is involved in the construction of molecules of numerous enzymes of catalysts for the decomposition of food substances, which create conditions for the use of their potential energy. Finally, phosphorus is widely represented in plastic processes, especially occurring in the skeletal system of an animal organism.
When characterizing the physiological role of magnesium, it should be noted that it is important for normalizing the excitability of the nervous system, has antispasmodic and vasodilating properties and has an effect on lowering blood cholesterol levels. It was also noted that with its deficiency, the calcium content in the muscles and walls of arteries increases. There is evidence that magnesium salts inhibit the growth of malignant neoplasms and, thus, have antiblastome action. Finally, it is known that it participates in the processes of carbohydrate, phosphoric and calcium metabolism, and its excess adversely affects the assimilation of the latter. Speaking of macronutrients that make up food, it is necessary to note the importance of potassium, sodium, chlorine and sulfur. The first of them plays an important role in intracellular metabolism, some enzymatic processes, the formation of acetylcholine and contributes to the removal of fluid from the body.
Sodium ions are to a certain extent physiological antagonists of potassium, and its compounds (bicarbonates and phosphates) are directly involved in the formation of buffer systems that provide an acid-base state and a constant osmotic pressure. As for chlorine, it in the composition of sodium chloride serves as one of the regulators of water metabolism and is used for the synthesis of hydrochloric acid by the glands of the stomach.
Finally, sulfur is an important structural component of some amino acids, vitamins and enzymes, as well as part of insulin.
Turning to a brief biological description of microelements, it is necessary to emphasize that their content in food products of plant and animal origin is subject to large fluctuations, since it depends on the geochemical features of the area. One of the most striking examples in this regard is the change in the concentration in the soil of iodine and fluorine, which is the cause of the appearance of peculiar endemic diseases. It is interesting to note that at present, of the elements included in the periodic table, more than 60 have already been found in the composition of living organisms. However, it is sometimes very difficult to say which of these elements seem vital and which ones accidentally fall from the surrounding environment. Nevertheless, what we know allows us to conclude that they play a huge role in our body, which was first suggested by the prominent Russian biochemist TA Bunge.
Iron is one of the most studied trace elements, the main importance of which is its participation in the process of blood formation. In addition, it is an integral part of protoplasm and cell nuclei, is part of oxidative enzymes, etc. Copper and cobalt take part in the synthesis of hemoglobin and other gedesoporphyrins along with iron, the latter also affects the formation of reticulocytes and their transformation into mature red blood cells.
As for manganese, it is obviously an activator of oxidation processes, has a pronounced lipotropic effect, and also serves as one of the ossification factors that determine the state of the bone tissue. However, it has a stimulating effect on the processes of growth and activity of the endocrine apparatus.
Of the other microelements, zinc attracts attention, and, according to some researchers, its role in the body is no less important than iron. In particular, there is evidence of the participation of this element in the blood, the activity of the pituitary, pancreas and sex glands, as well as its importance as a growth factor. Finally, zinc affects the content of vitamins in food products, and the enrichment of soils with them contributes to the synthesis of ascorbic acid and thiamine by plants.
Everything said about the role of macro-and micronutrients makes it necessary to ration them in the diet of the population. In this regard, the average adult's need for a number of mineral substances is more or less determined.
However, the currently accepted official recommendations include, for the time being, the relevant standards for only the three most important trace elements. At the same time, relatively detailed differentiation of these standards is available for children, adolescents, pregnant and lactating women, and adults.
The number of mineral vital substances must be attributed, and water, the lack and excess of which in our diet is harmful to the body.
At the same time, water starvation is most heavily tolerated by man and it is much more dangerous than food starvation, leading to death in a few days. However, its excessive consumption contributes to a large load on the heart, increases the processes of protein breakdown and increases fat formation. It is established that the daily need for water is determined by the conditions of the external environment, the nature of the work and the amount of food taken. Thus, the water balance of an adult person on average is determined by the following values: soups 500–600 g, drinking water 800–1000 g, contained in solid products 700 g and formed in the organism itself 300–400 g
Vitamins are low molecular weight organic compounds that are biologically active in insignificant concentrations. Their value for the body is extremely large, as they are necessary for the normal course of all biochemical reactions, the assimilation of other nutrients, growth and repair of cells and tissues. As catabolic factors, vitamins serve as catalysts for metabolic processes, playing the role of coenzymes, participating in the formation and functions of enzyme systems. Their anabolic significance has also been established, which consists in the organization and development of tissues, organs and structural formations of the organism. This applies to the development of the embryo, the formation of the skeleton, skin and mucous membranes, visual purpura, the synthesis of amino acids, purine and pyrimidine bases, the formation of acetylcholine, steroids, etc.
An important role is played by vitamins to maintain a person’s high resistance to the effects of adverse environmental factors and infectious onset, so that they can be used as a prophylactic agent when exposed to chemicals, ionizing radiation and other occupational hazards.
Vitamin preparations are becoming more widely used in the treatment of infectious diseases, after surgical operations, to eliminate the side effects of antibiotics, sulfonamides, etc. As a result, the principle of balance of vitamins in the diet becomes one of the essential requirements of therapeutic dietology.
With a certain degree of vitamin deficiency, a known gap between assimilative and dissimilatory processes can occur and dysfunction of systems and organs may appear. Ultimately, this should lead to the onset of dystrophic changes, and, according to a fair opinion of V. A. Engelhart, some vitamin deficiencies can be likened to afermentosis.
If during more or less long time the amount of vitamins in the diet is insufficient, then a peculiar pathological state develops. Usually this condition, called hypovitaminosis, is manifested by a sharp drop in the body's resistance to infectious onset, a pronounced decrease in performance, weakening of memory, etc. Early diagnosis of hypovitaminosis can be quite difficult due to non-specific symptoms, but is facilitated by appropriate laboratory studies. For example, C-hypovitaminosis can be established by reducing the concentration of ascorbic acid in the blood and reducing its excretion in the urine.
In the case of a significant deficiency of certain vitamins may develop avitaminosis, i.e., elementary diseases, accompanied by more severe and characteristic manifestations.
It should be noted that from the moment of transition to malnutrition to the pronounced manifestation of the disease often takes several weeks and even months. This is due to the presence in the body of stocks of these substances, which are particularly significant for fat-soluble vitamins. Sometimes, avitaminosis and especially hypovitaminosis develop rapidly, which is usually associated with past infectious diseases, debilitating physical exertion, and other causes of the depletion of the body's vitamin depot.
Perhaps the emergence of so-called subhypovitaminosis states, the development of which is explained by the ingestion into the human body of not optimal, but minimally sufficient doses of vitamins over a long period. As a result, complex and important biochemical processes are disturbed, state of health worsens, performance decreases, and resistance to harmful external influences decreases. Moreover, in conditions of limited vitamin nutrition, obviously, such potential possibilities in the development and functioning of the organism, such as its longevity, the duration of the blooming age and the ability to reproduce offspring, cannot be achieved.
The main cause of avitaminosis and hypovitaminosis is the lack of vitamins in food. However, these pathological and pre-pathological conditions can also develop with an ample content of these nutrients in the diet as a result of the deterioration of their absorption, increased destruction and accelerated elimination from the body. Thus, all diseases associated with impaired vitamin nutrition can be divided according to their etiology into two groups: primary, or exogenous, caused by a lack of vitamins in the diet, and secondary, or endogenous, associated with their absorption.
It should be emphasized that beriberi is completely eliminated as a mass disease in all regions of the Soviet Union. This, unfortunately, does not apply to hypovitaminosis, the prevention of which is an important task for the doctor of any profile. The latter is all the more important because the lack of certain vitamins in the diet is able to contribute to the development of a very dangerous age-related pathology. Thus, over-nutrition, combined with a deficit of ascorbic acid, may be one of the causes of early atherosclerosis and premature aging of the body. A certain value in the occurrence of cerebral hemorrhage has a lack of vitamin P, which also has a hypotensive effect. It is also assumed that choline deficiency plays a role in the pathogenesis of alimentary cirrhosis of the liver. Finally, a violation of the use of vitamin B 12 in the digestive tract causes pernicious anemia.
It is established that the vitamin requirement of the body depends on very many conditions relating to its physiological state, professional characteristics of work, the impact of external factors, etc. Thus, the relevant standards increase with physical activity and mental stress (C, PP, B1), exposure to high temperature (C, B1, PP), underground work (C, B1, D), toxic exposure (C, B1, etc.), in conditions of the Far North (C, B1, B2, D) and a number of other factors. It is enough, for example, to say that increased water intake and increased perspiration in hot workshops will contribute to the washing out of water-soluble vitamins. At the same time, vitamin metabolism increases significantly with infectious diseases, endocrine disorders, after surgical operations and long-term treatment with certain drugs (sulfonamides, antibiotics).
Особого внимания заслуживает повышенная потребность в витаминах беременных женщин, кормящих матерей и детей всех возрастов. Несколько возрастает эта потребность и в старческом возрасте, что, очевидно, можно связать с нарушениями пищеварительных и обменных процессов. Следовательно, нормативы витаминного питания должны полностью соответствовать нуждам человека, учитывая половые и возрастные различия, особенности труда и быта, климатические условия и др. Важное значение имеет не только предупреждение недостаточности витаминов в пище, но и обеспечение оптимального их количества. Это повышает созидательные силы организма, способствует росту и восстановлению тканей, благоприятствует течению процессов метаболизма, поддерживая их на более высоком уровне. Вместе с тем при построении любого рациона питания необходимо сбалансирование содержания витаминов, как между собой, так и по отношению к другим компонентам пищи. Нарушение данного принципа может отрицательно сказаться на общем метаболизме и не дать ожидаемого положительного эффекта.
Как известно, витамины главным образом синтезируются в растениях, причем человек их получает либо непосредственно с растительной пищей, либо через продукты животного происхождения. Кроме того, в образовании некоторых из них (например, витаминов группы В) играет роль микрофлора кишечника. Наконец, витамин D может синтезироваться при воздействии ультрафиолетовых лучей на содержащийся в кожных покровах 7,8-дегидрохолестерин, являющийся естественным провитамином.
Ценность основных носителей витаминов — фруктов и овощей — в значительной мере зависит от условий произрастания, способов хранения и кулинарной обработки. Естественно, что в весенне-зимний период полноценность питания может понижаться благодаря ограниченному ассортименту данных продуктов и уменьшению их витаминной активности. Это в первую очередь относится к содержанию аскорбиновой кислоты, наиболее легко разрушающейся при воздействии кислорода, особенно при повышенной температуре. Возникающий витаминный дефицит может быть восполнен за счет специальной витаминизации продуктов питания и готовых блюд, а также приема витаминных препаратов. Необходимо, однако, подчеркнуть, что проведение указанных мероприятий требует определенной осторожности и должно осуществляться под медицинским контролем. Нельзя забывать о том, что введение в организм повышенного количества витаминов может привести к тяжелым последствиям — развитию витаминной интоксикации (гипервитаминоз). Классическим примером гипервитаминоза могут служить случаи гибели людей, отравившихся печенью белого медведя, содержащей огромные дозы витамина А. Известны также опасные последствия передозировки витамина D в педиатрической практике при профилактике и лечении рахита. Более легкие формы гипервитаминозов наблюдаются при приеме водорастворимых витаминов. Так, введение в течение суток нескольких сот миллиграммов тиамина вызывает возбуждение, бессонницу, головную боль, сердцебиение и ряд других симптомов.
Следует отметить, что в последнее время накопились данные о том, что принятые в большинстве стран нормативы витаминного питания, в том числе и для аскорбиновой кислоты, несколько повышены и недостаточно сбалансированы.
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