Mineral substances are involved in the regulation of acid-base balance in the body, regulate water-salt metabolism, maintain the necessary composition and concentration of salts in cells and intercellular fluids, which ensures the circulation of nutrients and metabolic products between them due to the difference in osmotic pressure. Without minerals, the normal function of the nervous, cardiovascular, digestive and other systems is impossible. Minerals, especially trace elements, are part of or activate the action of enzymes, hormones, vitamins and thus participate in all types of metabolism, and also affect the protective functions of the body. Their role is very important in the construction of body tissues, especially bones. The processes of hematopoiesis and blood clotting also cannot occur without the participation of iron, copper, manganese,
Mineral substances are an indispensable part of the diet, and their long-term deficiency or excess leads to metabolic disorders and various diseases. During heat treatment of plant products, the loss of minerals is about 10%, animals – 20%. With improper cooking (prolonged cooking of peeled vegetables, defrosting meat in water), the loss of minerals increases significantly.
Potassium in food
Potassium plays an important role in the most important metabolic reactions of the body, in the regulation of water-salt metabolism, osmotic pressure, acid-base balance. Minerals – potassium – is necessary for normal muscle activity, in particular the heart, promotes the excretion of water and sodium from the body. Most of all potassium enters the body with plant products, meat, sea fish. The average potassium content in food is 150-170 mg%. Sources of potassium in food are mainly found in dried fruits (dried apricots, raisins, prunes) – about 2000 mg%, that is, 2 g per 100 g. Much of it is found in legumes: beans – 1100 mg%, peas – 870 mg%; in potatoes – 570 mg%, in apples and grapes – 250 mg% each, a person’s daily need for potassium is 3-4 g.
Sodium and chlorine
Sodium and chlorine enter the body mainly in the form of sodium chloride (table salt). Sodium plays an important role in intracellular and interstitial metabolism, regulation of acid-base balance and osmotic pressure in cells, tissues and blood, promotes the accumulation of fluid in the body, and activates digestive enzymes. Chlorine is involved in the regulation of osmotic pressure and water exchange, the formation of hydrochloric acid in gastric juice. The saltier the foods, the more sodium and chlorine they contain.
Table salt content (in percent, or grams per 100 g of product): bread – about 1; salted butter – 1.5; cheeses – 1.5-3.5; boiled sausages, sausages – 2-2.5, smoked sausages – 3-3.5; fish: lightly salted – 5-8, medium-salted – 9-14, hot smoked – 2, cold smoked – 8-11; salmon caviar – 6, sturgeon – 4; canned food: fish – 1.5-2, meat and vegetable snacks – 1.5, for baby and diet food – 0.3-0.8. There is little sodium in vegetables, fruits and cereals.
The daily requirement for table salt is 10-12 g and is satisfied by ready-made food products and salt, which is used for cooking and added to ready-made meals during meals. Sodium and chlorine deficiency occurs mainly as a result of salt-free diets, which are prescribed for hypertension, kidney disease and other diseases. In the initial stage, it manifests itself as a loss of taste and appetite, nausea, lethargy, and muscle weakness. In these cases, it is necessary to introduce “salt days” into the diet (take 5-6 g of table salt during the day).
Calcium forms bone tissue, participates in the transmission of electrical impulses through the nervous system, muscle contraction and blood coagulation, and reduces vascular permeability. It is a necessary component of the nucleus and membranes of cells, cellular and tissue fluids, affects the acid-base balance of the body, activates a number of enzymes, has an anti-inflammatory effect and reduces allergies.
In terms of content and completeness of assimilation, dairy products are the best sources of calcium. They provide 4/5 of the total need for this element. Milk contains 120 mg% calcium, cheese – about 1000 mg%. The absorption of calcium depends on its ratio with other nutrients. With an excess of phosphorus in food, in particular in the form of phytins of cereals and legumes, insoluble, scrapped calcium compounds are formed in the intestine. A pronounced excess of phosphorus in food can lead to the excretion of calcium from the bones. Calcium is absorbed from the intestines in the form of a complex with fatty and bile lots. Both lack and excess of fat in food impairs the absorption of calcium. Magnesium is absorbed in the same way; its excess is able to bind in the intestine some of the fatty and bile acids necessary for the absorption of calcium. Oxalic acid, which is rich in spinach, sorrel, figs, and chocolate, impairs the absorption of calcium from the intestines. With a deficiency of vitamin D, the absorption of calcium in the intestine is sharply disrupted, and the body begins to use bone calcium. Both lack and excess of protein in the diet impairs calcium absorption. According to the standards adopted in Russia, the daily requirement for calcium for healthy adults 18-59 years old is 800 mg. In older people, pregnant and lactating women, the need for calcium increases to 1000-2000 mg. The daily requirement for calcium for healthy adults 18-59 years old is 800 mg. In older people, pregnant and lactating women, the need for calcium increases to 1000-2000 mg. The daily requirement for calcium for healthy adults 18-59 years old is 800 mg. In older people, pregnant and lactating women, the need for calcium increases to 1000-2000 mg.
Phosphorus compounds take part in all life processes, but are especially necessary for the normal metabolism and functioning of the nervous and brain tissue, muscles, liver, kidneys, the formation of bones and teeth, which contain 85% of all phosphorus in the body, as well as enzymes and hormones. Phosphorus is a part of nucleic acids – carriers of heredity, and adenosine triphosphate – an energy store.
The daily requirement for phosphorus for adults is 1200 mg. Phosphorus in food is so widespread that its deficiency is very rare, only in those cases when a person eats exclusively vegetables, fruits and berries for a long time, in which there is little phosphorus. In addition, in plant products, phosphorus is contained mainly in the form of phytins, which are poorly absorbed by the human body. Phosphorus-rich foods include legumes and grains. Foods containing phosphorus: beans – 480 mg%, peas – 330 mg%, oatmeal, pearl barley, barley – 320-350 mg%, bread – about 200 mg%. However, only 40% of phosphorus is absorbed from plant products in the intestine, and 70% from animals. The best sources of phosphorus are animal products. Meat contains about 180 mg% phosphorus, fish – about 150 mg%.
Magnesium in nutrition is necessary for the production of energy, the metabolism of glucose, amino acids, fatty acids, vitamins of group B. It participates in the process of bone formation, normalizes the activity of the nervous system and the heart, has an antispastic and vasodilating effect, stimulates the motor function of the intestines and bile secretion. Plant foods are rich in magnesium.
The daily requirement for magnesium in food is 400 mg. Almost half of it is satisfied with bread – it contains 50 mg% magnesium. A lot of magnesium in nuts – 170-230 mg% and in legumes – about 100 mg%. Vegetables are poor in magnesium – 10-40 mg%, dairy products – 13-23 mg%. The absorption of magnesium can be impaired due to an excess of fats and calcium in food, the absorption of which in the intestine also occurs with the participation of bile acids.
Iron in foods is essential for normal blood formation and tissue respiration. It is part of the hemoglobin of erythrocytes, which delivers oxygen to organs and tissues, myoglobin – a protein that provides muscle contraction, enzymes involved in the processes of cellular respiration.
Iron in human food is partially absorbed from the intestines into the blood. The most fully absorbed iron is hemoglobin and myoglobin – blood and muscle proteins. Therefore, animal and bird meat, meat by-products are the best sources of iron. Iron is especially abundant in the liver and kidneys of animals and in legumes — 6–20 mg%. White bread made from premium flour is relatively poor in iron – 0.9 mg%.
The absorption of iron is facilitated by citric and ascorbic acids, as well as fructose, which are found in fruits, berries and their juices. Oxalic acid and tannins impair the absorption of iron, therefore, iron is practically not absorbed from spinach, sorrel, blueberries or quince, although it is contained in them in large quantities. Iron absorption is impaired in intestinal diseases and, to a lesser extent, with a decrease in the secretory function of the stomach.
The daily iron requirement for men is 10 mg, for women – 18 mg. The higher need for iron in women is due to its loss in blood during menstruation. For older women and men, the recommended intake of iron is the same: 10 mg per day.
With iron deficiency in the body, cellular respiration worsens, which leads to dystrophy (malnutrition) of tissues and organs and disruption of the body’s condition even before the development of anemia (anemia). Severe iron deficiency leads to hypochromic anemia. The development of iron deficiency states is facilitated by an insufficient intake of iron from food, in particular, the abundance of animal proteins in the diet and the creation of vitamins and minerals participating in the blood. Iron deficiency conditions, including anemia, are widespread, especially in women of childbearing age.
Iodine is involved in the formation of thyroid hormones, which have a versatile effect on the metabolism and the state of organs and systems of the body as a whole. In regions with a natural lack of iodine in soil, water and local food products, iodine deficiency conditions, decreased functions and diseases of the thyroid gland, including endemic (common in a certain area) goiter occur. The development of these diseases is to some extent promoted mainly by carbohydrate nutrition, lack of animal proteins, some trace elements (copper, manganese, cobalt, etc.), vitamins C and A.
All over the world, the best way to prevent iodine deficiency diseases is the massive use of iodized table salt, but iodine is also found in products. In Russia, iodine deficiency is observed in a significant part of the population, which is also facilitated by a decrease in the consumption of sea fish and seafood rich in iodine (squid, shrimp, mussels, seaweed and others). In the late 1990s, the Government and the Ministry of Health of the Russian Federation recognized the fight against iodine deficiency diseases in the country as a top priority. Over the past 2-3 years, the production of iodized salt in Russia has increased more than 10 times, but the demand for it is still satisfied by only 20%, so do not forget about iodine-rich foods.
The daily requirement for iodine for healthy adults is 150-200 mcg. 1 g of iodized salt contains an average of 40 mcg of iodine. The average daily intake of salt in different people is from 5 to 10 g. Therefore, the intake of iodine when using only iodized salt (taking into account the loss of about half of iodine during storage and cooking) is 100-200 μg per day. A dose of iodine up to 500 mcg per day is considered safe (physiological). Doses in excess of 1000 mcg per day are pharmacological (therapeutic).
Products containing iodine – sea fish and seafood, it contains about 80-100 mcg% iodine, in seaweed – 500-800 mcg%. There is little iodine in freshwater fish, meat, and vegetable products. It should be borne in mind that during the culinary processing of animal products, from 35 to 75% of iodine is lost. When baking bread, losses reach 80%, when cooking cereals and legumes – 50-65%, vegetables – 30-60%, meat – 50%.
Fluorine, together with calcium and phosphorus, is involved in the construction of bones and teeth and ensures their hardness and strength. Lack of fluoride in water and food contributes to the development of dental caries and a decrease in bone strength; its excess leads to the occurrence of fluorosis (damage to bones, tooth enamel, fragility of the teeth).
The daily requirement for fluoride is 0.5-1.0 mg. About 65% of fluoride enters the body with water, 35% – with food, from which fluoride is absorbed worse than from water. There is a lot of fluoride in sea fish (on average 700 mg%) and in seafood, as well as in tea – a cup of tea may contain 0.1-0.2 mg of fluorine. Dairy products, fruits, berries, and most vegetables are low in fluoride. In many countries, tap water is fluoridated if the fluoride content in it is below hygienic standards.
Zinc is part of more than 200 enzymes involved in a wide variety of metabolic reactions. It is necessary for the processes of hematopoiesis and bone formation, the activity of the male gonads, pituitary gland, adrenal glands, pancreas. Insulin is 0.36% zinc.
Algae and other seafood, meat and internal organs of animals, eggs of birds are rich in highly assimilable zinc. Fruits, berries and vegetables are poor in zinc; zinc, found in cereals and legumes, is poorly absorbed in the intestines. In children, zinc deficiency leads to impaired growth, underdevelopment of the gonads. In adults, zinc deficiency rarely leads to severe manifestations. Lack of zinc can be the cause of skin diseases and dysfunction of the male sex glands, increases the likelihood of developing prostate adenoma. There is evidence of impaired wound healing with a lack of zinc in the diet. The daily requirement for zinc for adults is 15 mg.
Copper participates in the formation of hemoglobin, bone formation and synthesis of hair pigments, is a part of or activates enzymes involved in tissue respiration.
The daily requirement of an adult for copper is about 2 mg. Copper is found in foods, for example, meat and liver of animals, sea and freshwater fish, non-fish seafood, cereals, potatoes, nuts, many fruits, berries and vegetables. Dairy products are poor in copper, and it is poorly absorbed from egg yolks.
Due to the variety of food sources of copper, its deficiency in the body in adults is rare – only with severe protein deficiency and severe intestinal diseases. The need for copper may increase with anemia (anemia).
Selenium, along with vitamins E and C, as well as carotenoids, is an antioxidant – it prevents the harmful effects of free radicals on cellular and intracellular structures. Selenium has a positive effect on the immune system, increases resistance to radiation.
Good sources of selenium are sea fish and seafood, liver, meat, eggs. Yeast is the best source of selenium in terms of quantity and good absorption. The amount of selenium in cereals and legumes depends on its content in the soil. Diseases caused by selenium deficiency have been identified in those places where the predominant nutrition of the population with grain products is combined with a low content of it in the soil.
The daily requirement for selenium for healthy adults is 50-100 mcg. Exceeding this norm is dangerous, since even with a small excess of selenium, its toxic effect manifests itself.
Chromium: vitamins and minerals
Chromium is part of enzymes that, along with insulin, regulate carbohydrate metabolism. The approximate daily requirement for chromium in an adult is 200 mcg. Good sources of chromium are wholemeal bread, legumes, liver, meat, fish, and yeast. There is little chromium in fruits, berries and most vegetables. Chromium deficiency develops as a result of gross eating disorders – a prolonged excess of easily digestible carbohydrates in the diet. With a pronounced lack of chromium, cholesterol metabolism is disturbed, and the body’s resistance to glucose decreases and a condition similar to diabetes develops. The use of chromium in the treatment of atherosclerosis and diabetes mellitus has yielded conflicting and so far unconvincing results.
For the normal metabolism and vital activity of the body, minerals are needed, such as manganese, molybdenum, cobalt and such conditionally irreplaceable trace elements as silicon, vanadium, boron, nickel. As a rule, foodstuffs contain a sufficient amount of these microelements, and diseases caused by their deficiency practically do not occur in humans.