Vitamin A belongs to the group of fat-soluble compounds (lipovitamins). It is able to be deposited in the body, mainly in the liver.

According to the WHO, with hypovitaminosis in vitamin A, none of the food products can cover its deficiency, and therefore the intake of retinol in the form of pharmacological preparations is required.

Vitamin A is formed in the body from provitamins - "carotenoids" coming from outside. The term comes from carrot (carrot, English), since these precursor substances were first discovered in carrots. Related compounds are present in a wide range of vegetables and fruits (especially yellow, red and orange), as well as in algae and certain types of fungi.

Currently, more than half a thousand carotenoids are known to science.

The most common of these are:

• a-, b- and d-carotene;
• zeaxanthin;
• lutein;
• lycopene.

Beta-carotene undergoes oxidation in the human liver, and, splitting, forms vitamin A.

The unit of measurement for retinol is 1 ER, which corresponds to 1 µg of retinol, 6 µg of b-carotene, or 12 µg of other carotenoids.

1 mcg is 3.33 IU for retinol or 10 IU for b-carotene.

Important:it has been experimentally proven that beef, skimmed milk, and cereals contain insufficient amounts of carotene and retinol, i.e., they cannot serve as full-fledged sources of vitamin A.

Animal foods containing vitamin A:

• beef liver;
• Cod liver;
• fish fat;
• sea ​​fish caviar;
• whole milk;
• cream;
• egg yolk.

Plant Sources:

• carrot;
• tomatoes;
• pepper ("Bulgarian" and hot cayenne);
• spinach;
• broccoli;
• parsley;
• parsley;
• peas;
• soya beans;
• apples;
• (kelp seaweed).

Important:in large quantities, provitamin A is present in herbs such as alfalfa, horsetail, pepper, lemongrass, nettle, sage, hops, and plantain.

Vitamin A is involved in a number of metabolic processes in the human body. It plays an important role in the regulation of protein biosynthesis and ensures the stability of cell membranes. The connection is necessary for the formation of bone tissue, as well as enamel and dentin. Thanks to him, the fat reserves necessary for a person are formed.

Note:It has been known since ancient times that liver consumption improves visual acuity and helps prevent or cure night blindness.

Retinol is necessary for adequate photoreception (perception of light); it takes part in the biosynthesis of retinal pigment. The most important carotenoids prevent cataracts and significantly reduce the likelihood of developing macular degeneration, a pathology that is one of the main causes of blindness.

Vitamin A is one of the most effective natural antioxidants. It minimizes the damaging effects of free radicals, which allows the use of retinol and carotenoids for prevention and treatment (as part of complex therapy) oncological diseases. In clinical studies, it has been proven that b-carotene reduces the likelihood of recurrence of malignant neoplasms after surgery.

The antioxidant effect helps prevent the development of a number of serious pathologies of the heart and blood vessels.

Vitamin A is able to increase the serum concentration of high density lipoproteins necessary for the body.

The carotenoid lycopene, which is found in large quantities in tomatoes, prevents the deposition of cholesterol on the vascular walls, thus protecting a person from its dangerous consequences. This provitamin also reduces the likelihood of developing malignant and breast cancer, as well as prostate cancer.

The state of non-specific depends largely on vitamin A. The compound is able to increase the body's resistance against infectious agents of a bacterial and viral nature (the phagocytic activity of leukocytes is significantly increased).

Sufficient intake of vitamin A with food reduces the likelihood of developing colds, as well as infections of the genitourinary and respiratory systems and organs of the gastrointestinal tract.

Children who eat well and regularly receive retinol and carotenoids in the right amount are much easier to tolerate "" and.

The constant presence of a sufficiently high level of retinol in the serum significantly increases the life expectancy of patients suffering.

Vitamin A is actively involved in the process of regeneration of the epithelial layer of the skin and mucous membranes. Its preparations are widely used in the treatment of any (, etc.), as well as skin damage due to mechanical injuries or burns. Due to the stimulation of the collagen biosynthesis process, retinol ensures the fastest healing, greatly reducing the risk of developing secondary infectious complications. Vitamin A significantly improves the quality of tissue that is newly formed at the site of significant damage.

Note:many modern cosmetic preparations include retinoid substances, which are nothing more than synthetic analogues of vitamin A. Retinoid creams are very good for sunburn.

The beneficial effect of retinol on epithelial cells improves the functional activity of the bronchi and lungs. Receiving vitamin A preparations for patients can speed up recovery from such pathologies of the digestive tract as peptic ulcer and colitis (inflammation of the mucous membranes of the walls of the large intestine).

Retinol is one of the most important organic compounds needed for the normal intrauterine development of the unborn child.

Women who are preparing to become mothers are advised to consume sufficient amounts of vitamin A to improve the nutrition of the fetus and reduce the likelihood of having an underweight baby.

For pregnant women, the daily intake of retinol should be 750-770 micrograms. Recommended for breastfeeding mothers Russian doctors the norm is more - 1200-1300 mcg.

Important: during childbearing, you can not consume more than 6000 IU per day, because high doses have a teratogenic effect on the fetus. For the same reason, during pregnancy, women are categorically contraindicated in fish oil.

How much vitamin A is required per day?

The average intake of vitamin A for an adult is 3300 IU (1000 mcg) per day. Against the background of pathologies caused by hypovitaminosis A, it is recommended to increase consumption by 3 times (up to 10,000 IU).

Important:climatic conditions can affect the body's need for vitamin A. Cold weather has no effect on retinol metabolism, but a hot climate makes its own adjustments: the need for this vitamin increases significantly.

Babies in their first year of life need 400 micrograms of retinol per day. Children from 1 to 3 years old need 450 mcg of the vitamin, those aged 4 to 6 years need 500 mcg, and from 7 to 10 years old 700 mcg per day.

For teenagers, the rules are the same as for adults.

Note:the need is reduced in women who take birth control pills.

Hypovitaminosis: causes and symptoms

Plasma vitamin A levels are considered insufficient if they are below 0.35 µmol/L.

Even at a level of 0.70-1.22 µmol / l, the amount of retinol in its main “storage”, i.e., in the liver, is noticeably reduced.

The main reasons for the development of hypovitaminosis include:

For the full assimilation of vitamin A, it is necessary to consume a sufficient amount of fat and complete protein. It must be present in food, the absence of which makes it difficult to absorb retinol.

Important:hypovitaminosis A is often observed in vegetarians who do not replace animal products with the necessary amount of high-grade vegetable protein.

The characteristic manifestations of hypovitaminosis include:

• increased temperature sensitivity;
• lowering the pain threshold;
• early aging of the skin (the appearance of wrinkles);
• dryness and peeling of the skin;
• redness of the eyelids;
• feeling of "foreign body" or "sand" in the eyes;
• accumulation of mucus and the formation of crusts in the corners of the eyes;
• urinary incontinence (sphincter weakness);
• hyperesthesia (pathologically high degree of sensitivity) of tooth enamel;
• deterioration of erectile function;
• early ejaculation.

A very characteristic manifestation of retinol deficiency is hemeralopia - a significant deterioration in vision at dusk.

Consequences of vitamin A deficiency:

• xerophthalmia (dryness of the cornea of ​​​​the eyes);
• clouding of the cornea;
• precancerous pathologies and skin cancer;
• atrophic gastritis;
• intestinal inflammation;
• pancreatitis;
• decrease in sexual desire;
• mastopathy;
• malignant tumors of the mammary glands;
• gynecological diseases (etc.);
• cachexia (exhaustion);
• anemia (anemia);
• frequent respiratory infections;
• cystic formations of the liver;
• insomnia.

Indications for taking vitamin A

Vitamin A is prescribed orally, for injection (IM) or for topical application, if diagnosed:

• pathology of the skin and mucous membranes;
• inflammation of the cornea and conjunctiva of the eyes;
• burns, fractures and other injuries (to accelerate regeneration).

Mild and moderate hypovitaminosis require doses up to 33,000 IU for adult patients and from 1,000 to 5,000 for children. For skin diseases, the dosages are higher - 50000-100000 and 5000-10000 IU, respectively.

Hypervitaminosis

Important:vitamin A has a toxic effect on the body when consumed 25,000 IU per day.

Symptoms of hypervitaminosis:

• pain in the abdominal region;
• hepatosplenomegaly;
• alopecia;
• arthralgia;
• "Zaedy" in the corners of the mouth;
• delay of menstruation;
• dry skin;
• increased fragility and thickening of the nail plates.

Important:a lack of zinc leads to a violation of the absorption of retinol.

The combination of vitamin A and ethanol causes more significant liver damage than alcohol exposure.

In modern conditions, our visual organs are subject to a wide variety of loads. Prolonged work at the computer, and exposure to ultraviolet rays, and various stresses and depressive states that, perhaps, every person has encountered. All this has a very Negative influence. Like any other organ, they need vitamins that can not only prevent the development of many ophthalmic pathologies, but also have a rather positive effect on the entire body as a whole.

One of the most useful for our organs of vision is considered to be vitamin A, which is also called retinol, or carotene. It plays a huge role in the full-fledged work of our visual organs, as it promotes the processes of cell division and growth and improves immunity. Its deficiency leads to a violation of color perception and hemeralopia - a deterioration in vision in a dark room, also popularly called "night blindness". In addition, the lack of this substance in the human body can provoke the drying of the cells of the cornea, and also be expressed in increased tearing and a constant feeling of tired eyes.

Today, few people know that it was retinol that became the first low molecular weight organic compound discovered by scientists at the beginning of the last century. Then the researchers came to the conclusion that the yolk of a chicken egg and butter contain a common substance that has a relationship with lipoids - fat-like components of natural origin. Based on this information, biologists were able to prove that in butter contains a unique active agent that cannot be destroyed under the influence of alkalis. It was then called "fat-soluble factor A", which was later changed to the well-known today - vitamin A.

Retinol is both a fat-soluble vitamin and an antioxidant. This suggests that it is perfectly soluble in fats, therefore it easily accumulates in our body. It is in connection with the possibility of such an operative accumulation that an overdose is possible. In addition, many people whose diet is unbalanced try in every possible way to replenish its amount through the use of special multivitamin complexes, which can be purchased today at any pharmacy. Unfortunately, most of them do not think that in the end this can have a very negative impact on health and even lead to general intoxication of the body.

Why is an overdose so dangerous? The fact is that a large accumulation of a certain component can provoke a malfunction of many organs and lead to such a dangerous disease as cirrhosis of the liver - a pathological condition of the organ, which is a consequence of impaired blood circulation in the hepatic vascular system and dysfunction of the bile ducts. According to doctors, the main symptoms of an overdose are an increase in the size of the liver and spleen, intestinal upset and nausea. In addition, drowsiness may increase, the work of the central nervous system may be disturbed. Some patients complain of severe joint pain, high blood pressure and bleeding gums.

Vitamin A is present today in two main forms. The first is, in fact, retinol itself, contained in animal products. The second is provitamin A, also called carotene, which comes from plant products. As a rule, the first group is easily absorbed in the digestive tract. The second, when it enters the intestines, is first transformed into retinol, and then absorbed by the body. Up to 90% of the total amount of this substance is usually absorbed into the blood, after which it combines with proteins and further enters the liver.

The importance of vitamin A for the human body is very difficult to underestimate. The spectrum of its action is very wide. So, for example, it is necessary for normal protein synthesis and metabolism, as well as the proper division of body fat. In addition, it slows down aging and promotes the growth of new cells. We have already spoken about the significance of the presented substance for the visual organs. It is authentically known that in ancient times, healers prescribed boiled liver to their patients to treat night blindness. Among other things, it plays a huge role in our perception of light. With its deficiency, the full functioning of the immune system and the protection of the body from certain infections are impossible. It increases the resistance of the mucous membrane to various viruses, and also protects the respiratory tract from dangerous infections.

Modern researchers note that in countries with a high standard of living, children easily tolerate diseases such as measles, rubella, chicken pox. In less developed countries where there is a shortage of the vitamin, these diseases can even cause deaths. In addition, it is simply necessary for pregnant women, as it is able to normalize the weight of a newborn baby. Accordingly, its quantity obtained in a particular region is one of the critical factors fertility and reduction of perinatal mortality. Among other things, not so long ago, scientists published data that retinol helps maintain the required level of glucose in the blood, thereby helping insulin to be absorbed as efficiently as possible. If, after the studies, these data are confirmed, then its use can have a significant impact on the treatment of such dangerous diseases as diabetes, obesity and hypertension.

What products contain this ingredient? This question is being asked today by many people who are concerned about their health. First of all, these are all products of plant origin. The source of a fairly large amount is the well-known parsley, peppermint, plantain leaves, sage, rose hips, nettle and sorrel. To replenish stocks, you can include carrots in your daily diet - the main source of carotene, as well as pumpkin, bell pepper, broccoli and green onions. Regular consumption of legumes, such as soy or peas, will not hurt. Fruits such as apples, peaches, apricots, melons, as well as berries, ranging from cherries to watermelons, are also rich in them.

A large amount of retinol can also be obtained from animal products: fish oil, liver (especially beef), caviar. As well as dairy products: butter, sour cream, margarine, cheese and cottage cheese. Regular consumption of the above products can not only replenish the reserves of this component in the human body to the required level, but also normalize health, generally preventing many different diseases.

At different periods of life, a person should consume a different amount of low molecular weight organic compounds per day. For example, for newborns daily allowance until they reach the age of six months is 400-600 mcg. In the next six months, the dose is slightly increased and the minimum amount should not be lower than 500 mcg. Children under eight years old should consume no more than 900 micrograms, and from nine to thirteen years old - from 600 to 1700 micrograms. Upon reaching the age of 14, daily consumption rates change significantly, which is explained by the peculiarities of the functioning of the body. The minimum dose for an adult should not be less than 6 mg. As a rule, doctors recommend consuming an average of 15 mg per day, since this is the amount that is necessary to maintain health.

Do not forget that any, even the most useful and seemingly safe substance should be used very carefully. So, for example, with long-term use of carotene, vitamins of group E should be taken at the same time, since a lack of the latter can interfere with normal absorption. Zinc contributes to the transformation of retinol into its active form, therefore it is important to maintain its normal amount in the body. When taking multivitamin complexes containing the above substance, you should stop drinking alcoholic beverages, since liver damage is very likely during the interaction. It is also worth avoiding the use of drugs that lower blood cholesterol levels, because they can interfere with the normal absorption of fats.

What to do if, for one reason or another, it is not possible to regularly consume a vitamin in a natural way? In what form is this substance presented in pharmacies? Most often, people who want to replenish its supply purchase oil solutions for intramuscular injections or for external use and ingestion. Also popular are capsules, which many consumers refer to as film-coated tablets. Multivitamin complexes can be in the form of a dragee, syrup or soluble powder.

Before you start using, you should consult with a qualified specialist and, ideally, be tested. This is important to do in order to avoid side effects. As you know, it is worth limiting yourself to people prone to allergic diseases, as they can suffer from asthma attacks and other asthmatic manifestations provoked by uncontrolled intake of drugs. People suffering from hypothyroidism, a disease of the endocrine system that occurs due to a lack of thyroid hormones in the thyroid gland, should also be careful.

Retinol, or vitamin A, is known in pharmacology as one of the most useful fat-soluble substances. But why does it have such a name, which means "vitamin A"?

Known in modern pharmacology, it got its name not by chance - this is the first vitamin discovered by man, and since the beginning of the last century it has been called in Latin the first letter of the alphabet. The properties and biochemical functions of retinol are so wide that it is probably easier to name those industries where it has not found its application than the areas of use. But still, we will try to tell as much as possible about the beneficial properties of the number one vitamin.

Discovery history

The history of the discovery of vitamin A dates back to 1909, when the German scientist Shtepp launched a series of experiments on mice. The animals were first fed bread mixed with milk, but as soon as food was added to the diet after extraction with alcohol and ether, the growth of the experimental animals stopped and they died. This made it possible to make a scientific discovery: the extraction of bread with organic solvents removed lipoids necessary for the life of animals from it.

In 1913, two more groups of researchers made a different conclusion: without lipoids (found in chicken yolks and butter), the development of mammals is impossible. A year later, after carefully studying the chemical structure of the oil, scientists found an element later called "fat-soluble factor A", or "growth factor". In short and in simple terms, the main conclusion of many years of experiments was that the body is able to absorb retinol only in the presence of fats. Other important discovery scientists: the substance that is part of carrots, pumpkins, persimmons and other yellow-orange fruits promotes the growth of mammals and resumes the development process. This pigment was named daucus carota, or carotene (which means "carrot" in Latin), then group A vitamins began to be called carotenoids. In 1916, the first chemical formula of a discovered substance became the subject of detailed study. Scientists were interested in what it consists of, where it is located, what it is useful for and how to remove the vitamin in the laboratory. After the Second World War, the process of industrial production of retinol started, the chemical nature and structural formula of the substance became known.

Today he is studying chemical and biological processes of obtaining vitamin A biotechnology. We will not touch on the narrow professional terminology and study what the coenzyme form is or recall the empirical name of the vitamin. Let's talk about the properties of retinol in a simpler and more accessible language, but based on facts from different sciences.

Interestingly, under the name "vitamins of group A" pharmacology means several substances:

• retinol, or, as vitamin A in oil is called, retinol acetate;
• dehydroretinol;
• retinoic acid;
• retinal (active form A1).

They are different forms of vitamin A from the general group - retinol. The functions of dehydroretinol and retinol are to promote the formation of tissues and the adequate functioning of the reproductive system. Retinal is indispensable for eye health, and retinoic acid improves the development of the epithelium. But more often, group A vitamins are not separated, and when used, the physicochemical properties characteristic of the entire group of substances are taken into account.

Vitamin A properties

1. Retinol in its pure form is a substance with a crystalline structure. Its color is light yellow. This is why fruits and vegetables with yellow pigments are known as foods rich in vitamin A.
2. It has the ability to dissolve in fats and does not dissolve in water.
3. There are different types of vitamins: natural and artificial. Manufacturers have made sure that the beneficial properties of retinol are more pronounced in synthetic isomers. But such, at first glance, a positive moment hides the main danger: an overdose when using pharmacy vitamins is not uncommon, since retinol in tablets or capsules is more concentrated than its natural counterpart.
4. When products containing retinol are heated, 15-20% of the vitamin is destroyed. The storage of food in the sun is detrimental to the "growth factor": the structure of the molecule is quickly destroyed under the influence of ultraviolet radiation and oxygen.

Before starting to talk about natural sources of vitamin A, to study which food has the most of it, it is important to emphasize that there are two forms of "growth factor". The first is retinol itself, so to speak, a true “ready-made” vitamin. His body receives from animal products. The second form is beta-carotene, or the so-called provitamin A, and retinol is produced from it in the liver as a result of an oxidative cleavage reaction. Sources in nature for beta-carotene - plant foods.

By the way, oversaturation or poisoning with a vitamin is almost impossible if its reserves are replenished exclusively from fruits and vegetables.

With this basic knowledge, it is possible to study in more detail which foods contain substances of group A.

Foods rich in retinol

As already noted, most natural retinol is in food of animal origin. Have a great vitamin value:

• fish fat;
• caviar;
• liver (beef), heart, brain;
• fatty milk, cream, cottage cheese, cheese;
• chicken yolk.

Foods Containing Beta Carotene

Vitamin A is a part of such plants:

• yellow, green vegetables;
• fruits are yellow, red;
• spicy greens;
• herbs (nettle, plantain, dandelion, horsetail, sage, hops, mint, bearberry, clover, alfalfa);
• burdock root;
• violet leaves, raspberries;
• rose hips, hawthorn.

If you create a rating of products that contain vitamin A, then the first place, unconditionally, will be taken by food of animal origin. Find out which foods contain the highest amount of retinol, perhaps by studying chemical composition food.

So to say, a shock dose of natural vitamin A is found in the liver, caviar, quail and chicken eggs. Among the products of plant origin, the champions are hawthorn and dandelion, 100 g of which can provide the body with 160 percent of the daily requirement of beta-carotene. The daily requirement of provitamin will be provided by 100 g of fresh carrots or 200 g of wild garlic. Also, do not forget about the presence of carotenoids in brightly colored vegetables and fruits.

Daily rate

Except natural sources, synthetic derivatives of vitamin A are capable of providing the body with retinol. It would seem that in the heyday of pharmacology, biochemistry will take care of human health: he took a complex of vitamins, the chemical properties of which correspond to natural analogues, and you can not be afraid of beriberi, forget about the need to think over the diet. But before you drink vitamin A capsules, it is important to realize that in reality everything is not so simple. For full-fledged work, the body must receive vitamins and microelements in its main share from natural sources, and only for “pulling up” daily indicators is it allowed to use a synthetic analogue from time to time.

It is logical that the daily requirement of a vitamin for men, women and children is not the same. For people of different age categories, the vitamin norm is also different. Moreover, the daily allowance in mg is determined differently for residents of different climatic zones working in different conditions. The comparative table contains information on the daily requirement of the vitamin for residents of our latitudes.

The figures collected in the table show how much vitamin A is needed per day at certain periods of body development. The traditional daily norm in some cases may vary. For example, the dosage is adjusted for people with obesity, diseases of the gastrointestinal tract and liver, patients with viral and bacterial diseases. A doctor may prescribe an increased dose of retinol for people who regularly spend several hours a day at a computer, working mentally or in darkened rooms, as well as with increased physical activity. Climatic conditions can influence the indications for the use of the vitamin and its dosage. A temperate and cold climate usually does not require correction of the daily vitamin dose (of course, if we are talking about healthy people). But residents of sunny, hot regions should take care of increasing the consumption of retinol.

Another important note regarding dosages. Experts from the World Health Organization convince that the source of ¾ of the consumed vitamins of group A should be food of animal origin, the rest - from plants.

The fact that the balanced use of a complex of vitamins is of great importance for the body is known to everyone. But still, what is vitamin A for, what is it responsible for and what does it affect? In order to understand how important the function of vitamin A in the human body is, it is necessary to understand what processes retinol regulates.

The biological role of the vitamin consists of several aspects. Carotenoids have no equal when it comes to restoring the skin, treating the eyes, and preventing cancer. This antioxidant vitamin is involved in the process of activating the immune system, has a beneficial effect on bone tissue, and its positive effect on the reproductive system has been proven. The versatility and beneficial properties of retinol have made it one of the best known and most used vitamins.

Where and how is retinol used?

1. Vitamins of group A take part in metabolism, regulate metabolism.
2. Retinol promotes the formation of proteins and the growth of new cells. Indispensable for babies during the formation of bones and teeth, for the growth of a teenager. In sports, it is known as a substance that has a beneficial effect on muscles (accelerates growth).
3. Important for the eyes - prevents a number of ophthalmic diseases, helps maintain sharp vision in poorly lit rooms.
4. Anti-infectious vitamin improves immunity, protects against colds and viruses, is used to prevent acute respiratory infections.
5. It is well known for its beneficial properties for the treatment of acne and pimples. Vitamin A is an excellent medicine for psoriasis, it quickly heals wounds, including post-burn ones. Eliminates wrinkles and stretch marks of the skin after a sharp change in weight. In cosmetology, vitamin A has found application as a universal beauty remedy.
6. It is part of comprehensive programs for the treatment of infertility, prevention of cancer, indispensable for the gastrointestinal tract - a good medicine for the gastric mucosa in gastritis.
7. An antioxidant vitamin is an important component of drugs for blood vessels and heart disease.
8. Found practical application in veterinary medicine.

When a vitamin is low...

Lack of retinol can cause many diseases. To find out the real amount of vitamin A in the human body, laboratory diagnostics, such as a routine blood test, will help. Although in most cases, especially if vitamin deficiency is "neglected", the symptoms of the disease, as they say, are on the face. So, what occurs in the absence of vitamin A in the body, what are the signs of hypovitaminosis?

The consequences of a lack of vitamins of group A are more than serious. In particular, retinol deficiency leads to a disease known as night blindness.

Poor vision, drying of the mucous membrane of the eyeball, clouding of the cornea, a feeling of "sand" in the eyes and discomfort in dark rooms - such symptoms in adults and children are caused by a lack of carotenoids. If you do not use eye drops, the unpleasant effects of the disease will only progress.

Hypovitaminosis A and neuralgic problems also go together. The most common disorder is insomnia.

The lack of an adequate dose of retinol affects the quality of the skin (early appearance of wrinkles, follicular hyperkeratosis - “toad skin”, acne), teeth (enamel is destroyed), hair (dry and lifeless), dandruff appears, the genitourinary and digestive systems suffer.

In gynecology, signs of vitamin A deficiency are considered in such manifestations as erosion, polyps, mastopathy and even cancer. Also, the male reproductive system suffers from a lack of carotenoids: potency decreases, erection weakens, spermatozoa are not viable, and the risk of oncological ailments increases.

When there is not enough vitamin A, the immune system weakens, the body becomes more sensitive to viral diseases, colds. In children, in addition to a tendency to frequent acute respiratory infections, there are signs of a slowdown in physical and mental development, growth stops.

At the first sign of a decrease in the level of vitamin A in the body, it is better to immediately adjust your diet than to replace natural retinol with its chemical analogue.

Causes of Vitamin Deficiency

But what are the reasons for the lack of carotenoids in the body and how to protect yourself from such unpleasant consequences? The most common reason for the occurrence of hypovitaminosis A is poor nutrition (insufficient intake of protein and fatty foods). In second place - ailments digestive system(improper functioning of the organs, in particular, the altered structure of the liver prevents the absorption of the vitamin). The third equally important reason is marriage, which also affects the absorption of retinol. At risk - adhering to a low-calorie diet for weight loss. Usually the diet is a food devoid of fat, and with a deficiency of lipoids, the absorption of carotene is impossible.

Realizing the incorrectness of the diet, you can take a complex of synthetic vitamins - pharmacy analogues of retinol as your “helpers”. It would seem that this is bad? But, trying to compensate for the lack of a vitamin with the help of medications, it is easy to go to the other extreme - to provoke an excess of the substance. In addition, this can be achieved quite quickly: pharmacy retinol accumulates in the body several times faster than organic.

Hypervitaminosis disrupts the functioning of most systems, and a disease with an excess of vitamin is as dangerous as beriberi.

There are two forms of hypervitaminosis A - acute and chronic. The first form is the result of a single dose of the vitamin before meals or after meals in a particularly large dose.

Symptoms of acute hypervitaminosis:

• pain in the joints, bones, abdomen;
• corners of the mouth in cracks;
• hair loss and destruction of the structure of the nail plates;
• weakness, sweating (mainly at night), irritability;
• headache accompanied by vomiting;
• violation in women menstrual cycle;
• deterioration of the digestive system, enlargement of the liver and spleen.

But is it possible to achieve hypervitaminosis exclusively with food? Answer: No, it's practically impossible. The exception is the inhabitants of the polar latitudes. Only regular consumption of the liver of northern animals, which contains a large amount of vitamin A, can cause a natural overabundance of retinol.

Chronic excess is a consequence of its systematic use in excessive doses. This form of hypervitaminosis is more common. You can understand that vitamin A in the body is in excess by different symptoms. The intensity of their manifestation depends on the amount of accumulated substance.

Signs of excess (chronic form): allergic reactions (itching, redness), peeling of the skin, pigmentation, insomnia, or vice versa - drowsiness, confusion, irritability, swelling along the bones, sores in the mouth, bleeding gums, irregular periods, indigestion, nausea, pseudojaundice, double vision, hair loss, dandruff. Newborns with hypervitaminosis are threatened by hydrocephalus. An excess of the maximum daily dose of the vitamin, consumed daily for several years, is the key to cirrhosis of the liver.

It is extremely dangerous to exceed the allowable rate of retinol for pregnant women. Regular receipt of more than a daily dose leads to improper formation of the genitourinary system of the fetus, slows down its growth, the child can be born with serious defects. Correction of the daily dose of vitamins is carried out even when planning pregnancy. The method of application of the drug is exactly according to the instructions.

Compatibility with other substances

The pharmacy assortment offers a variety of multivitamin combinations that promise to restore the reserves of all useful substances for the body. But resorting to the help of tableted vitamins is the second step. The first is to adjust the diet, replenish the menu with foods rich in retinol. This is easiest to do in the summer when beta-carotene containing plants are available.

However, one often has to deal with a situation that seems strange at first glance: the daily diet is varied, full of products valuable for the body, but blood tests are still not the best. So why is vitamin A not absorbed?

First, as already noted, it is important to know what retinol is best absorbed with. And the regulation of this indicator depends to a large extent on fats. The absence of sebaceous food in the diet eliminates all attempts to replenish carotenoids. That's why even pharmacy counters have fish oil with vitamin A.

Secondly, when compiling a menu, combining products, it is important to know how to drink vitamins correctly, that is, the principles of their combination. As for carotenoids, they are best absorbed in combination with vitamin E or else. A good combination option is vitamin A and iron, in which case the body will get the maximum benefit from both substances. But with acetylsalicylic and hydrochloric acids, retinol should be taken separately. And you should not think about whether it is possible to drink with sorbents - with such a combination, carotene will not be absorbed.

For Women's Health

Retinol, along with vitamin E, is indispensable for women's health. By creating a positive effect on the hormonal balance, it contributes to the normal functioning of the gonads, regulates the menstrual cycle. Vitamin A is necessary for the breast with mastopathy, and is also important in the fight against benign formations in the mammary glands. Retinol in combination with folic acid is an effective remedy for eliminating menopausal symptoms.

During pregnancy

Pregnancy planning is a crucial stage for the expectant mother and child. Even six months before conception, it is worth taking care of the balance of vitamins, because for the next 9 months, the female body will have to provide itself and the fetus with the necessary trace elements. At this stage, it is important that the daily dose of vitamin A for the woman was calculated by the doctor and in no case should the dose be adjusted independently. It is better if vitamins and microelements important for conception are accumulated with food, and pharmacy medications and dietary supplements should be taken if there are no contraindications. Nevertheless, in order to exclude the negative effect of vitamin A on the fetus, synthetic substances should be avoided.

Benefits of retinol during pregnancy:

• promotes the formation of rhodopsin (visual pigment), the development of the placenta and fetus;
• strengthens the immune system;
• beneficial effect on sleep, heart function;
• strengthens nails and hair, improves skin condition.

During lactation

Studies show that beriberi is main reason reduction in lactation. For a nursing mother, rule number one is to monitor the level of vitamins in the body: the quality of milk depends on this indicator as the main measure. It is especially important for infants, whose body develops and grows rapidly, to receive a sufficient daily dose of vitamins during feeding, in particular the “growth factor” - vitamin A.

But taking the vitamin by mouth is not the only use of retinol by breastfeeding mothers. It is also applied externally. Many women during lactation and feeding the baby faced such a nuisance as cracked nipples. And again, vitamin A will come to the rescue - its oil solution. Using it for nipples breastfeeding, you can almost get rid of the problem: it is enough to treat the injured area 5-6 times a day with vitamin oil, the chemical name of which is retinol acetate.

For kids

You can talk a lot about how retinol is useful for babies. In the first years of life, when there are active processes of development of the body, the structure of the skeleton, vitamins of group A are important in the diet for the growth and proper development of bone tissues. But when there is a child in the house, vitamin A should be present not only on the plate in the form of food.

Parents should take care that retinol in liquid form does not disappear from the family first aid kit, as it can more than once come to the rescue faster than any ambulance, replacing ointments and nose drops.

For example, with stomatitis, retinol in oil will quickly relieve pain, medicinal properties vitamins will help heal wounds on the lips or palate, liquid retinol is indispensable for a runny nose in babies (drip 1-2 drops into the nose of a child twice a day).

Why do children need retinol?

• for the growth and development of the skeleton;
• for the formation of organs of the reproductive system;
• to protect the mucous membranes from microbes;
• for the prevention of diseases of the respiratory system;
• for sharp vision;
• acne in teenagers.

There is a need to take pharmacy retinol - it is better to ask the pediatrician which course of taking vitamin A capsules is best for the child.

For eyes

Even children know about the role of carotenoids for vision. From a very young age, we were told what it meant for eye health. However, the beta-carotene found in plants is only good for prevention. When the disease comes to the full, another form of vitamin A comes to the rescue - retinol drops. Moisturizing eye drops with vitamin A (antixerophthalmic vitamin) are good not only for treatment, but also for prevention, in particular for people whose work is connected with a computer.

Interestingly, it is the lack of retinol that causes the distortion of color perception, drying of the cells of the cornea and conjunctiva. The participation of vitamin A in the process of light perception has also been proven.

The consequence of vitamin deficiency - the visual analyzer loses the ability to perceive and distinguish light brightness. The distortion of light perception is the cause of the weakening of other possibilities of the visual apparatus.

Therefore, it is important to consult a doctor at the first symptoms of the disease and discomfort, and always have eye drops with vitamin A on hand.

Impact on the endocrine system

Recent studies have revealed interesting facts about the effect of vitamin A on the body of patients diagnosed with diabetes. Under the influence of retinol, the production of insulin in diabetes increases, as a result of which the blood sugar level stabilizes. This helps, if not completely cancel insulin injections, then at least reduce the dosage of the drug.

The lack of vitamin A and magnesium adversely affects the functioning of the thyroid gland: it loses its protective properties, and disruptions in the endocrine system cause metabolic disorders, decreased immunity.

When they talk about how dangerous hypovitaminosis A is for the body, leukemia is called among the most serious problems - a disease that often develops against the background of thyroid disease. The best disease prevention is proper nutrition. It is important to include in your daily diet a list of foods rich in vegetable beta-carotene and animal retinol.

Oncology and retinol

Useful properties of vitamin A modern medicine uses often and effectively. One of the latest revolutionary discoveries beneficial effect retinol for the treatment of cancer patients. Experiments have shown that daily use of retinol throughout the year slows down the formation of metastases in the postoperative period. A course of taking a vitamin as a prophylaxis can protect against the formation of malignant tumors. Retinol acetate is known as a drug that treats skin cancer.

Speaking of cancer. It has been proven that smokers are 25 times more likely to get cancer than people who healthy lifestyle life. Smoking can cause cancer of the throat, lips, larynx, palate, and even pancreas and bladder. And even children know about the dangers of tobacco smoke for the lungs. Therefore, it is especially important for smokers to monitor the level of vitamin A in the body. Daily use of retinol for six months will relieve such a disease as leukoplakia (it is caused by chewing tobacco).

For teeth and bones

Retinol, synthesized in bone and cartilage tissue, is indispensable during the growth period of children and teenagers. Vitamin is important for teeth (makes them strong, even, snow-white) and for gums (strengthens, makes smooth, healthy Pink colour). Hypovitaminosis becomes the cause of stomatitis, periodontal disease (alarm signal - bleeding gums), destruction of tooth enamel.

There are two ways to make up for the lack of retinol in the child's body: by resorting to synthetic analogs of the vitamin and by adjusting the diet. Eggs, fish liver, caviar, carrots, fatty milk, broccoli, bell peppers, that is, everything related to vitamin A, should be present on a children's plate.

For infectious diseases

The anti-infective properties of vitamin A were known long before vitamin C, and there is no way to fight infections without immune-boosting retinol. The argument in favor of vitamin A is the results of studies that have shown that in more developed countries, children do not die from banal infectious diseases, such as measles, and regular use of retinol can eliminate complications in case of chickenpox. Undoubtedly, resistance to infections is achieved in different ways: this is vaccination, and personal hygiene. But it is also the maintenance of vitamin and mineral balance.

Speaking about the anti-infectious and immunostimulating properties of vitamin A, one cannot but recall AIDS. The description of scientific experiments convinces that even a slight but regular use of retinol can slow down the development of the disease. You can get vitamin A for HIV-infected people with food, but this will not be enough. AIDS is the disease when you can not do without the additional intake of retinol in the form of pharmaceutical preparations or dietary supplements. At the same time, it is important to regularly measure the level of the vitamin in the patient's body in order to avoid overdoses.

in sports nutrition

Regular restoration of energy reserves is essential for the full and high-quality functioning of the body. Especially when it comes to people who are intensively engaged in physical activity. Special nutrition for athletes usually consists of carefully calculated proportions of proteins, vitamins and trace elements that contribute to muscle growth.

And since retinol is an important part of sports nutrition, there is an opinion that they get better from vitamin A. In fact this is not true.

Vitamin A in bodybuilding is indeed a revered substance used in weight gain complexes, but in this case, the change in body weight is not due to body fat, but due to muscle growth. Sports nutritionists, knowing about the ability of retinol to accelerate the formation of new cells, used this function to build muscle tissue. In addition, vitamin A is an indispensable substance in the process of protein synthesis.

But novice athletes should know: during a period of intense exercise, it is important to use retinol regularly and in large doses - with food (when making a menu for a week, take into account which foods have vitamin A in them), drink its pharmacy counterpart. You can not be afraid of overdoses, since with intensive calorie burning, the absorption of vitamin A worsens.

A sports menu rich in vitamins of group A should consist of milk, eggs, spinach, carrots, fish, liver, tomatoes, peppers, apricots, parsley, dill.

In cosmetology and skin problems

In cosmetology, vitamin A has found its application as a rejuvenating component. Due to its low molecular weight, it is able to penetrate deep into the skin, protecting and restoring its structure.

Retinol acetate for the skin is used as a remedy for age spots and stretch marks.

AT cosmetic purposes Vitamin A is used in creams:

• for the body (tones, relieves irritation);
• for hands (softens, nourishes);
• for legs (from cracks in the heels);
• for the face (for acne).

Also in cosmetics, the properties of retinol are used in hair masks (improves the structure, treats dandruff), in cuticle and nail products, eyelashes, eyebrows, lips.

Use for cosmetic purposes, involves the combination of vitamin A with other useful components. The most popular mix is ​​a complex of vitamins A and E. If you add a few drops of vitamins to an oil base (for example, from wheat germ), you get an excellent tool for eyelash growth. The same mixture can be used for eyebrow growth. To prepare creams, add vitamins A, E, B in liquid form (in ampoules or in the form of an oil solution) to the finished base. The finished mixture can be equally effectively used both for heels - retinol acetate heals cracks and microdamages of the skin, and for the face - it will provide acne treatment. Also, zinc oxide can be added to the composition of the cream fortified with retinol - suitable for oily skin, dry up acne. But it is worth remembering the school curriculum, for example, what the reaction of vitamin A with sulfuric acid looks like in order to understand: retinol is absolutely incompatible with acids.

Vitaminizing the cream, introduce retinol into it (especially if the drug is prepared for sensitive skin) in minimal portions - no more than 0.1-0.5% of the total volume. As the skin adapts, the amount of vitamin can be slightly increased.

A liquid solution of retinol is also good for soap making. But, so that the substance does not lose its useful properties during cooking, add it to the already prepared soap mixture.

Recently, mesotherapy is gaining popularity - rejuvenating injections of vitamin A.

For nails and cuticles

Well-groomed hands are a visiting card of a woman. Do you want to be proud of healthy and beautiful nails? Then, among cosmetics, take the main place for vitamin A. Retinol in combination with vegetable oils contributes to rapid growth nails, restores and protects them, moisturizes and softens the cuticle. It is enough to rub a few drops of the oil mixture into the fingertips in the evenings, and in the morning to compare how the nail looks - the result will exceed all expectations. Not sure how to choose an effective nail care product? Why not cook it yourself?

Recipe number 1 for nails and cuticles

Mix oils:

• vegetable (almond, coconut, grape seed, apricot or other);
• essential (lemon, rosemary, orange or tea tree);
• vitamins E and A in oil form.

Mix ingredients thoroughly. Store in the refrigerator in a dark bottle. Rub daily for a month.

Recipe number 2

Mix in a bottle (glass, dark color) 1 ml of vitamin A and E, add 3 ml of apricot oil and 6 ml of jojoba oil. Mix. Pour in 2 drops of lemon essential oil and 4 drops of rosemary essential oil. Rub daily into the cuticle and nail with massaging movements. The product creates a firming effect, regular use will ensure healthy nails, relieve plate delamination, cuticle dryness, and stains on the nails.

Retinol for peeling

The active form of vitamin A, or as retinoic acid is called in chemistry, has found its application in cosmetology as an effective peeling drug. Retinoic yellow peeling is a procedure that stimulates the process of epidermal cell renewal and skin rejuvenation.

How does vitamin A peeling help?

Indications for peeling: uneven skin color on the face, acne, sagging cheeks. It has proven itself in dermatitis, accelerates the treatment of acne. The frequency of procedures is 1-2 for a month and a half. Depending on the additional components, the peeling mixture is left on the skin for different periods: sometimes no longer than an hour, in other cases - at night. The result of an improper procedure is allergy and intoxication.

Useful properties of yellow peeling:

• rejuvenates;
• enhances the protective functions of the skin;
• strengthens local immunity (creates a barrier to bacteria);
• reduces the risk of pustules;
• accelerates wound healing;
• brightens the skin (in places of age spots);
• promotes cleansing of dead cells.

But in addition to many positive aspects, peeling with vitamin A in some cases can cause side effects. In particular, the procedure is prohibited for pregnant women, given the mild toxicity of auxiliary cosmetics.

From warts

The dosage form of vitamin A (retinol acetate) is an effective remedy for combating warts. The course of treatment is from several weeks to six months, and the procedure itself cannot be easier: daily rub oil-vitamin into warts. It is enough to do it once a day, preferably at night.

In veterinary medicine

Only two of the known 13 vitamins in excess can become dangerous to the health of both humans and animals. We are talking about vitamins A and D. It is important for pet owners to remember this if they decide to artificially fortify the animal's menu.

For the normal development of a cat or dog, a very small dose of retinol is enough, but a deficiency or excess of the vitamin causes serious disorders, in particular bone diseases. For animals, vitamin A is an excellent protection against infections, a substance to increase immunity, improve vision, and restore the epithelium; necessary for the normal development of embryos. In a word, the application in veterinary medicine is as wide as in medicine.

The course of treatment for dogs and cats is different. In particular, cats replenish their vitamin A reserves from substances of animal origin, that is, the “ready-made” vitamin retinol. Dogs are able to synthesize the necessary substance from beta-carotene. These features are explained by the difference in the metabolism of different groups of animals. But the course of vitaminization should be determined by a veterinarian, because hypervitaminosis is extremely dangerous for animals, therefore, the rate of consumption of synthetic retinol should be carefully observed.

Symptoms of hypovitaminosis in animals: impaired coordination, xerophthalmia, clouding of the cornea, epithelial damage.

Hypervitaminosis leads to diseases of the musculoskeletal system (lameness, fragility of the paws, tooth loss).

The use of various dosage forms

The pharmaceutical analogue of retinol is prescribed as a therapeutic agent and for prevention, it is taken externally, intramuscularly and orally. The release form of retinol is determined by the purpose for which the drug will be used.

What is sold in pharmacies?

Release forms:

• capsules;
• tablets of different dosages, including effervescent ones;
• dragee;
• solutions for injections;
• oily solutions for oral administration;
• oil extract (yellow liquid with a specific smell - like a fish smells);
• vitamin A concentrate;
• ointment;
• powder (in granules).

How to use different forms of vitamin?

• oil solution. Outwardly. For dressings, lotions for eczema, ulcers, burns, frostbite, for healing wounds. Clean the wounded surface, apply an oil solution on it and cover the treated area with sterile gauze folded in 2 layers. Repeat the procedure 6 times a day. It is also possible to take an oil solution inside, but it is important to know how to use the drug correctly. To do this, you need to drip 10-20 drops of oil on a piece of black bread. Take three times a day after meals. Course duration - from 2 weeks to 4 months;
• tablets, dragee. For the prevention and treatment of beriberi and in cardiovascular diseases. Take 3-5 tablets after meals for a month. Then a 2-month break and repeat. The reception scheme is the same;
• ointment with vitamin A. Apply to wounds, problem areas of the skin, with gout. In parallel with the external use of retinol, to enhance its action, take it orally (in the form of tablets, dragees or capsules);
• syrup containing vitamin A - with hypovitaminosis in babies;
• capsules - for diseases of the digestive, genitourinary, respiratory systems;
• injections intramuscularly - only in a hospital under the supervision of a doctor (with night blindness, severe beriberi).

How to store and use correctly?

The biochemical properties of synthetic vitamin A can be preserved for a long time only with proper storage of the drug. For each medication or dietary supplement, instructions for use are provided, which indicate how to take and save. Here we list the general rules for all.

1. Store the oil solution in a cool place.
2. Do not apply retinol and creams containing vitamin A at night - swelling may occur.
3. Remove excess cream or oil from the skin with a tissue.
4. Do not use an oil solution before visiting the solarium: such a tan can turn into a burn.
5. Do not use drugs that have expired.
6. Take a break between courses of application.
7. Using a retinol cream for the first time? Test it on a small patch of skin to rule out allergic reactions.

Vitamin A is a fat-soluble element that:

• improves vision and helps us see in the dark;
• participates in the differentiation of skin cells and mucous membranes;
• helps the body fight infection and support the immune system;
• stimulates bone growth and remodeling.

In addition, vitamin A in the form of beta-carotene (an antioxidant) may reduce the risk of certain types of cancer. Normal intake of vitamin A is essential for human health.

Why do you need vitamin A

Vitamin A deficiency can lead to night blindness (inability to see in the dark or recover vision quickly after exposure to a flash of bright light in the dark) and xerophthalmia (progressive blindness that becomes irreversible if left untreated).

Vitamin A deficiency can also impair the health and integrity of the skin and other epithelial tissues. Vitamin A deficiency can lead to dry skin and hyperkeratosis (development of skin clots around hair follicles).

Vitamin A deficiency in epithelial tissues can adversely affect digestion and nutrient absorption and cause infections of major systems and their organs (i.e., gastrointestinal tract, nervous/muscular, respiratory and genitourinary systems).

In addition, bone growth and remodeling can simply stop, which leads to a weakened immune system.

What happens from an overdose of vitamin A

Despite its benefits, too much vitamin A in the body can cause high toxicity, the effects of which can vary depending on its source. Excessive intake of vitamin A in food is not harmful, but causes yellow skin. Large doses (10-15 times the RDA) of vitamin A (retinol) per day are harmful and can lead to:

• development of fatty degeneration of the liver (hepatomegaly),
• dry skin,
• nausea, vomiting,
• fatigue,
• weakness,
• headaches,
• anorexia,
• increased risk of birth defects in the fetus of a pregnant woman.

• liver,
• fish fat,
• oils,
• milk,
• dairy,
• eggs.

The liver is a particularly rich source of vitamin A, since vitamin A is primarily stored in the liver of animals and humans. Vitamin A is also found in a variety of dark green and dark orange fruits and vegetables such as carrots, sweet potatoes, pumpkin, spinach, turnips, Chinese cabbage, and mustard.

Cooking (but not burning) increases the bioavailability of carotenoids in plant foods, and absorption of dietary vitamin A is improved when consumed along with certain fats in the same meal.

Vitamin A (Retinol) - role in the body, content in foods, deficiency symptoms. Instructions for use of vitamin A

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The site provides background information for informational purposes only. Diagnosis and treatment of diseases should be carried out under the supervision of a specialist. All drugs have contraindications. Expert advice is required!

vitamins are bioorganic low molecular weight compounds that are necessary for normal metabolism in all organs and tissues of the human body. Vitamins enter the human body from the outside and are not synthesized in the cells of its organs. Most often, vitamins are synthesized by plants, less often by microorganisms. That is why a person should regularly eat fresh plant foods, such as vegetables, fruits, cereals, herbs, etc. The source of vitamins synthesized by microorganisms are the bacteria of normal intestinal microflora. Thus, the importance of the normal composition of the intestinal microflora is obvious.

Depending on the structure and functions, each bioorganic compound is a separate vitamin, which has a traditional name and designation in the form of a letter of the Cyrillic or Latin alphabet. For example, the vitamin is denoted by the letter D and has the traditional name cholecalciferol. In medical and popular science literature, both options can be used - both the designation and the traditional name of the vitamin, which are synonyms. Each vitamin performs certain physiological functions in the body, and with its deficiency, various disorders in the functioning of organs and systems occur. Let's take a look at the different aspects of vitamin A.

What vitamins are referred to under the general designation "vitamin A"?

Vitamin A is the common name for three bioorganic compounds belonging to the group of retinoids. That is, vitamin A is a group of the four following chemicals:
1. A 1 - retinol (retinol acetate);
2. A 2 - dehydroretinol;
3. Retinoic acid;
4. The active form A 1 is retinal.

All of these substances are different forms of vitamin A. Therefore, when talking about vitamin A, they mean either any of the above substances, or all of them together. The common name for all forms of vitamin A is retinol, which we will use in the rest of this article.

However, in the instructions for biologically active additives (BAA), manufacturers describe in detail which chemical compound is included in their composition, not limited to the simple mention of "vitamin A". This is usually due to the fact that manufacturers indicate the name of the compound, for example, retinoic acid, after which they describe in great detail all its physiological effects and positive effects on the human body.

Basically, various forms Vitamin A plays a variety of roles in the human body. So, retinol and dehydroretinol are necessary for the growth and formation of normal structures of any tissue and the proper functioning of the genital organs. Retinoic acid is necessary for the formation of normal epithelium. Retinal is necessary for the normal functioning of the retina, as it is part of the visual pigment rhodopsin. However, usually all these functions are not separated by form, but are described together, as inherent in vitamin A. In the following text, in order to avoid confusion, we will also describe the functions of all forms of vitamin A without separating them. We will indicate that any function is inherent in a certain form of vitamin A only if necessary.

General characteristics of vitamin A

Vitamin A is fat-soluble, that is, it dissolves well in fats, and therefore easily accumulates in the human body. It is precisely because of the possibility of accumulation that fat-soluble vitamins, including A, are capable of causing an overdose with prolonged use in large quantities (more than 180 - 430 mcg per day, depending on age). An overdose, as well as a deficiency of vitamin A, leads to serious disruptions in the normal functioning of various organs and systems, primarily the eyes and the reproductive tract.

Vitamin A exists in two main forms:
1. Vitamin A itself retinol) contained in products of animal origin;
2. Provitamin A ( carotene) found in plant foods.

Retinol from animal products is immediately absorbed by the human body in the digestive tract. And carotene (provitamin A), getting into the intestines, first turns into retinol, after which it is absorbed by the body.

After entering the intestine, from 50 to 90% of the total amount of retinol is absorbed into the blood. In the blood, retinol combines with proteins and in this form is transported to the liver, where it is deposited in the reserve, forming a depot, which, if vitamin A intake from the outside is stopped, can be enough for at least a year. If necessary, retinol from the liver enters the bloodstream and, together with its current, enters various organs, where cells, using special receptors, capture the vitamin, transport it inside and use it for their needs. Retinol is constantly released from the liver, maintaining its normal concentration in the blood, equal to 0.7 µmol / l. When vitamin A is taken from food, it first enters the liver, replenishing the depleted reserves, and the remaining amount remains circulating in the blood. Retinal and retinoic acid in the blood are contained in trace amounts (less than 0.35 µmol / l), since in these forms vitamin A is present mainly in the tissues of various organs.

Getting into the cells of various organs, retinol turns into its active forms - retinal or retinoic acid, and in this form is integrated into various enzymes and other biological structures that perform vital functions. Without active forms of vitamin A, these biological structures are not able to perform their physiological functions, as a result of which various disorders and diseases develop.

Vitamin A enhances its action and is better absorbed in combination with vitamin E and the trace element zinc.

Biological functions of vitamin A (role in the body)

Vitamin A in the human body performs the following biological functions:

• Improve the growth and development of cells of all organs and tissues;
• Necessary for normal growth and bone formation;
• Necessary for the normal functioning of all mucous membranes and skin epithelium, as it prevents hyperkeratosis, excessive desquamation and metaplasia (cancerous degeneration of epithelial cells);
• Provide good vision in low or low light conditions (so-called twilight vision). The fact is that retinol is part of the visual pigment rhodopsin, which is located in the cells of the retina of the eye, called rods for a certain shape. It is the presence of rhodopsin that provides good visibility in conditions of weak, not bright lighting;
• Improves the condition of hair, teeth and gums;
• Improves the growth of the embryo, promotes the proper formation and development of various organs and tissues of the fetus;
• Enhances the formation of glycogen in the liver and muscles;
• Increases the concentration of cholesterol in the blood;
• Takes part in the synthesis of steroid hormones (testosterone, estrogens, progesterone, etc.);
• Prevents the development of malignant tumors of various organs;
• Regulates immunity. Vitamin A is essential for the complete process of phagocytosis. In addition, retinol enhances the synthesis of immunoglobulins (antibodies) of all classes, as well as T-killers and T-helpers;
• Antioxidant. Vitamin A has powerful antioxidant properties.

The list lists the effects of vitamin A at the level of organs and tissues. At the cellular level of biochemical reactions, vitamin A has the following effects:
1. Activation of the following substances:

• Chondroitinsulfuric acid (a component of connective tissue);
• Sulfoglycans (components of cartilage, bones and connective tissue);
• Hyaluronic acid (the main substance of the intercellular fluid);
• Heparin (thinns the blood, reduces its clotting and thrombosis);
• Taurine (a stimulant for the synthesis of somatotropic hormone, as well as a necessary link in the transmission of a nerve impulse from a neuron to organ tissues);
• Liver enzymes that ensure the transformation of various exogenous and endogenous substances;

2. Synthesis of special substances called somatimedins of classes A 1 , A 2 , B and C, which enhance and improve the formation of muscle proteins and collagen;
3. Synthesis of female and male sex hormones;
4. Synthesis of substances necessary for the functioning of the immune system, such as lysozyme, immunoglobulin A and interferon;
5. Synthesis of epithelial enzymes, which prevent premature keratinization and desquamation;
6. Activation of receptors for vitamin D;
7. Ensuring timely inhibition of cell growth, which is necessary for the prevention of malignant tumors;
8. Ensuring the completion of phagocytosis (destruction of a pathogenic microbe);
9. The formation of visual pigment - rhodopsin, which provides normal vision in low light conditions.

As you can see, vitamin A, in addition to providing good vision, has a fairly wide range of different effects in the human body. Traditionally, however, vitamin A has been associated only with effects on the eyes. This is due to the fact that the role of vitamin A for vision was studied earlier than all others, and this was done in great detail, while other effects and functions were identified later. In this regard, the idea that vitamin A is a substance necessary for normal vision has become fixed, which, in principle, is true, but does not fully reflect it, since in fact retinol also performs other, no less important functions.

Daily intake of vitamin A for people of different ages

A person in different age periods should consume different amounts of vitamin A per day. The daily intake of vitamin A for children of different ages, regardless of gender, is as follows:

• Newborns up to six months - 400 - 600 mcg;
• Children from 7 to 12 months - 500 - 600 mcg;
• Children from 1 to 3 years old - 300 - 600 mcg;
• Children from 4 to 8 years old - 400 - 900 mcg;
• Children 9 - 13 years old - 600 - 1700 mcg.

Starting from the age of 14, the norms of vitamin A intake for women and men differ, which is associated with the peculiarities of the functioning of organisms. Daily norms of vitamin A for men and women of different ages are presented in the table.

The table and the list show two numbers, the first of which indicates the optimal amount of vitamin A, necessary for man per day. The second number indicates the maximum allowable amount of vitamin A per day. According to the recommendations of the World Health Organization, only 25% of the daily requirement for vitamin A should be provided by plant foods. The remaining 75% of the daily requirement for vitamin A should be provided by animal products.

Insufficient intake of vitamin A leads to its deficiency, which is manifested by a number of disorders from various organs. However, an excess intake of a vitamin in the body can also provoke serious health disorders due to an overabundance or hypervitaminosis A. Hypervitaminosis A is possible due to the fact that retinol can accumulate in tissues and be slowly excreted from the body. Therefore, vitamin A should not be consumed in large quantities, believing that there will be nothing bad from such a useful substance. You should adhere to the recommended doses of vitamin A and do not exceed the maximum allowable daily dosage.

What foods contain vitamin A

Vitamin A in the form of retinol is found in following products animal origin:

• Chicken, beef and pork liver;
• canned cod liver;
• Beluga caviar is grainy;
• Egg yolk;
• Butter;
• hard cheeses;
• Fatty meats and fish.

Vitamin A in the form of carotenoids is found in the following plant foods:

• Cheremsha;
• Red bell pepper;

For a clear and quick understanding of whether this particular plant has vitamin A, you can use a simple rule - carotenes are found in all red-orange vegetables and fruits. Therefore, if a vegetable or fruit is painted in such a bright Orange color, then it definitely contains vitamin A in the form of carotenoids.

The content of vitamin A in various foods, the need for vitamin A - video

Symptoms of deficiency and hypervitaminosis of vitamin A

Vitamin A deficiency in the body leads to the development of the following clinical manifestations:

• Hyperkeratosis on the knees and elbows (severe peeling and dry skin);
• Follicular hyperkeratosis (toadskin syndrome);
• Acne;
• Pustules on the skin;
• Dry and dull hair;
• Brittle and striated nails;
• Disorder of twilight vision (night blindness);
• xerophthalmia;
• Corneal perforation followed by blindness;
• Deterioration of the activity of the immune system;
• Tendency to frequent infectious diseases;
• Weakened erection in men;
• Poor sperm quality;
• Increased risk of developing malignant tumors.

Hypervitaminosis A can be acute or chronic. Acute hypervitaminosis develops when a large amount of vitamin A is taken simultaneously. Acute hypervitaminosis A is most often observed when the liver of polar animals is used in food, which contains a lot of retinol. Due to the excessive amount of vitamin A, the inhabitants of the Far North (Eskimos, Khanty, Mansi, Kamchadals, etc.) have a taboo on the use of the liver of polar mammals. Acute hypervitaminosis A is manifested by the following symptoms that occur after consuming a large amount of retinol:

• Pain in the abdomen, bones and joints;
• General weakness;
• Malaise;
• Sweating at night;
• Headache associated with nausea and vomiting;
• Hair loss;
• Violation of the menstrual cycle;
• Violation of the digestive tract;
• Cracks in the corners of the mouth;
• Brittle nails;
• Itching of the whole body.

Chronic hypervitaminosis A is more common than acute and is associated with long-term use of retinol in doses slightly exceeding the maximum allowable. Clinical manifestations of chronic hypervitaminosis A are as follows:

• Itching and redness of the skin;
• Peeling of the skin on the palms, soles and other areas;
• Hair loss;
• Pain and swelling of soft tissues located along the long bones of the body (bones of the thigh, lower leg, shoulder, forearm, fingers, ribs, collarbone, etc.);
• Ligament calcification;
• Headache;
• Irritability;
• Excitation;
• confusion;
• double vision;
• Hydrocephalus in newborns;
• Increased intracranial pressure;
• Nausea and vomiting;
• Enlargement of the liver and spleen;
• Pseudojaundice.

The severity of symptoms of chronic hypervitaminosis varies depending on the concentration of vitamin A in the blood.

If a pregnant woman consumes vitamin A in a dosage above 5000 IU (1500 mcg) daily for a long time, this can cause a slowdown in fetal growth and improper formation of the urinary tract. Consumption of vitamin A during pregnancy in excess of 4,000 mcg (13,400 IU) may lead to congenital defects development in the fetus.

Vitamin A: benefits, deficiency symptoms, contraindications and signs of overdose - video

The use of vitamin A

The most widespread use of vitamin A is in cosmetology, the treatment of skin diseases, and also in the treatment of vascular diseases. In recent years, vitamin A has been widely used by gynecologists, andrologists and reproductologists in complex programs for the treatment of infertility and preparation for pregnancy. However, the complex scope of this vitamin is much wider.

So, vitamin A improves the growth and development of various organs and tissues, so it is recommended to give it to children to normalize the formation of bones, muscles and ligaments. In addition, retinol ensures the normal functioning of the childbearing process, so the vitamin is successfully used during pregnancy, during puberty and in women or men of reproductive age in order to improve the functioning of the reproductive system.

Vitamin A during pregnancy contributes to the normal growth of the fetus, preventing a delay in its development. In adolescents, vitamin A normalizes the development and formation of the genital organs, and also helps to adjust reproductive functions (maintains sperm quality, normal menstrual cycle, etc.), optimally preparing the bodies of girls and boys for future childbearing. In adults, vitamin A ensures the optimal functioning of the reproductive organs, which significantly increases the chances of conceiving, bearing and giving birth to a healthy baby. The most pronounced positive effect of vitamin A on reproductive function is observed when it is used in combination with vitamin E. Therefore, vitamins A and E are considered the key to the normal ability of men and women to bear children.

The function of vitamin A in providing good vision in low light conditions is widely known. With a lack of vitamin A, a person develops night blindness - a visual impairment in which he sees poorly at dusk or in low light. Regular intake of vitamin A is effective method prevention of night blindness and other visual impairments.

Also, vitamin A in people of any age and gender ensures the normal functioning of the skin and mucous membranes of various organs, increasing their resistance to infectious lesions. It is because of the huge role in maintaining the normal structure and functions of the skin that it is called the "beauty vitamin". Due to its positive effect on the skin, hair and nails, vitamin A is very often included in various cosmetic preparations - creams, masks, shower gels, shampoos, etc. The role of the beauty vitamin is given to retinol also because of its ability to reduce the rate of aging, maintaining the natural youth of women and men. In addition, retinoic acid is successfully used in the treatment of inflammatory and wound diseases of the skin, such as psoriasis, acne, leukoplakia, eczema, lichen, pruritus, pyoderma, furunculosis, urticaria, premature graying of hair, etc. Vitamin A accelerates the healing of wounds and sunburn. burns, and also reduces the risk of infection of wound surfaces.

Since vitamin A increases the resistance of mucous membranes to infections, its regular use prevents colds of the respiratory tract and inflammatory processes in the organs of the digestive tract and genitourinary system. Vitamin A is used in the complex treatment of erosions and ulcers of the intestine, chronic gastritis, gastric ulcer, hepatitis, cirrhosis of the liver, tracheitis, bronchitis and catarrh of the nasopharynx.

The antioxidant properties of vitamin A predetermine its ability to destroy cancer cells, preventing the development of malignant neoplasms of various organs. Vitamin A has a particularly strong preventive anti-oncogenic effect in relation to pancreatic and breast cancer. Therefore, vitamin A is used in the practice of oncologists as part of the complex treatment and prevention of recurrence of various tumors.

As an antioxidant, vitamin A increases the content of high-density lipoproteins (HDL) in the blood, which is very important for the prevention of cardiovascular diseases such as hypertension, coronary artery disease, heart attacks, etc. Therefore, large doses of vitamin A are currently used to treat vascular diseases.

Vitamins A for pregnant women

Vitamin A is very important for the normal course of pregnancy and the proper and full development of the fetus. From the point of view of a pregnant woman, vitamin A has the following positive effects on her body:

• Improves immunity, which prevents colds and other infectious and inflammatory diseases that pregnant women are susceptible to;
• Reduces the risk of developing infectious inflammatory diseases respiratory organs, digestive tract and genitourinary system, thereby preventing numerous recurrences of thrush, bronchitis, rhinitis and other pathologies that often develop in pregnant women;
• Maintains the normal condition of the skin, preventing the appearance of stretch marks (stretch marks);
• Maintains the normal condition of hair and nails, preventing their loss, brittleness and dullness;
• Helps ensure normal growth of the uterus;
• Maintains normal vision in pregnant women, and also prevents its deterioration;
• Supports the continuation of pregnancy, preventing preterm birth.

The listed effects of vitamin A favorably affect the general well-being of a pregnant woman, and, therefore, increase her quality of life and the likelihood of a favorable outcome. In addition, vitamin A relieves women from common problems associated with pregnancy, such as dull and falling hair, dry and flaky skin, cracking and exfoliating nails, stretch marks, constant colds and vaginal thrush, etc.

Vitamin A intake by a pregnant woman has the following positive effects on the fetus:

• Improves the growth and development of the skeletal system of the fetus;
• Normalizes the growth of the fetus;
• Prevents fetal growth retardation;
• Ensures the normal formation of the organs of the genitourinary tract in the fetus;
• Prevents fetal hydrocephalus;
• Prevents fetal malformations;
• Prevents premature births or miscarriages;
• Prevents infection with various infections that can cross the placenta.

Thus, vitamin A has a positive effect on both the pregnant woman and the fetus, so its use in therapeutic dosages is justified.

However, since an excess of vitamin A can adversely affect the course of pregnancy, causing miscarriages and fetal developmental delays, it should be taken only under the supervision of a doctor, strictly observing the prescribed dosages. The optimal daily dosage of vitamin A for a pregnant woman is no more than 5000 IU (1500 mcg or 1.5 mg).

Currently, in the countries of the former USSR, gynecologists often prescribe to pregnant women and women planning a pregnancy the Aevit complex preparation, which simultaneously contains vitamins A and E. Aevit is prescribed precisely because of the positive effects of vitamins A and E on reproductive function. However, this drug should not be taken by either pregnant women or women planning pregnancy, since it contains a huge dose of vitamin A (100,000 IU), which exceeds the optimal and recommended by WHO by 20 times! Therefore, Aevit is dangerous for pregnant women, as it can cause miscarriages, malformations and other disorders in the fetus.

Pregnant women without harm to the fetus can take complex preparations that contain no more than 5000 IU of vitamin A, for example, Vitrum, Elevit, etc. However, since vitamin A is not a completely harmless drug, it is recommended to do a blood test for the content of this substance before using it . Then, based on the concentration of vitamin A, determine the individual dosage that is optimal for this pregnant woman.

Vitamin A for children

Vitamin A is very important for the normal growth and development of the musculoskeletal system in children. That is why it is recommended to give it to children during periods of intensive growth, when the intake of the vitamin with food may not meet the increased needs of the body. In addition, vitamin A is very important for the proper formation of the reproductive organs during puberty, both in boys and girls. In girls, vitamin A contributes to the early establishment of a normal menstrual cycle and the formation of resistance of the vaginal mucosa to various infections. In boys, vitamin A contributes to the formation of a normal erection and the development of testicles with the formation of good quality sperm, which is necessary for future conception.

In addition, by increasing the resistance of the mucous membranes to various pathogenic microorganisms, vitamin A prevents frequent infectious and inflammatory diseases of the respiratory organs in children. Vitamin A also supports normal vision in a child. In adolescents, vitamin A is able to reduce the number of acne and pimples, which has a positive effect on the quality of life of the child.

It is because of the pronounced positive effect on the body that it is recommended to give the child vitamin A in preventive dosages of 3300 IU per day in short, periodically repeated courses. To do this, it is recommended to purchase either multivitamin preparations or special vitamin tablets with a prophylactic dosage of 3300 IU.

Preparations containing vitamin A

Currently, the following dosage forms are used as preparations containing vitamin A:
1. Natural plant extracts (included in dietary supplements).
2. Synthetic vitamins that completely imitate the structure of natural chemical compounds (included in one-component vitamin preparations and multivitamins).
Pharmacological preparations containing synthetic vitamin A include the following:

• Retinol acetate or retinol palmitate - tablets containing 30 mg (30,000 mcg or 100,000 IU of retinol);
• Retinol acetate or retinol palmitate - dragees containing 1 mg (1000 mcg or 3300 IU of retinol);
• Axeromalt - vitamin A concentrate in fish oil (1 ml of fat contains 100,000 or 170,000 IU of retinol) in vials;
• Oil solution of carotene;
• Aevit;
• Alphabet;
• Biovital-gel;
• Biorhythm;
• Vita Mishki;
• Vitasharm;
• Vitrum;
• Multi-Tabs baby and classic;
• Multifort;
• Pikovit;
• Polivit baby and classic;
• Sana Sol;

An oily solution of carotene is used externally in the form of dressings and lotions. The solution is applied to chronic eczema, long-term and poorly healing ulcers, burns, frostbite and other wounds of the skin.

Tablets containing 30 mg of retinol and Aevit are used only for medicinal purposes, for example, to eliminate vitamin A deficiency or to treat vascular and skin diseases. These tablets and Aevit cannot be used for prophylactic purposes in people of any age, since this can provoke hypervitaminosis, as well as hypovitaminosis, which is manifested by severe violations of the functioning of various organs and systems. All other drugs are vitamins used to prevent hypovitaminosis. Accordingly, they can be given to people of any age, including children and pregnant women.

Dietary supplements containing vitamin A in the form of natural extracts and extracts include the following:

• ABC Spectrum;
• Antioxidant capsules and dragees;
• Artromax;
• Viardot and Viardot forte;
• Wheat germ oil ;
• Metovit;
• Will direct;
• Nutricap;
• Oksilik;
• Blueberry forte.

All of the listed dietary supplements contain a prophylactic dosage of vitamin A, so they can be used periodically for short courses in people of different ages.

Vitamin A in a vitamin complex

Vitamin A is currently part of many complex preparations. Moreover, the absorption of vitamin A from complex preparations is no worse than from monocomponent agents. However, the use of multivitamins is very convenient for a person, because it allows him to take only one tablet. Complex multivitamins contain various vitamin compounds in the required preventive dosage, which is also very convenient for use. However, in these preparations there is a different dosage of vitamin A, therefore, when choosing a particular multivitamin, it is necessary to take into account the age and general condition of the person who will take it.

For example, for children of different ages and adults, the following complex preparations containing vitamins A are recommended:

• Children under one year old - Multi-Tabs Baby, Polivit baby;
• Children from 1 to 3 years old - Sana-Sol, Biovital-gel, Pikovit, Alphabet "Our baby";
• Children from 3 to 12 years old - Multi-Tabs classic, Vita bears, Alphabet "Kindergarten";
• Children over 12 years old and adults - Vitrum, Centrum and any dietary supplements (dietary supplements).

The best vitamins A

The best vitamins A do not exist, since each medicinal pharmacological preparation or dietary supplement has a spectrum of indications and its own dosage of retinol. In addition, each drug has an optimal effect for specific, individual disorders or for the prevention of well-defined diseases and conditions. Therefore, in the treatment of one disease, for example, a vitamin A preparation called "Aevit" will be the best, in the case of another pathology - Centrum vitamins, etc. Thus, for each case, a different drug containing vitamin A will be the best. That is why in medicine there is no concept of the "best" drug, but only the definition of "optimal", which in each case may be different.

However, one can very arbitrarily single out the "best" vitamins A for various conditions. So, relatively speaking, for the prevention of hypovitaminosis A in children, men, women and pregnant women, various multivitamin complexes will be the best. To eliminate an existing vitamin A deficiency or a general strengthening effect on the body, single-component tablets or dragees containing at least 5000 IU of retinol acetate or palmitate will be the best. For the treatment of vascular diseases, inflammatory processes on the mucous membranes of the respiratory, digestive and genitourinary organs, as well as infectious and inflammatory, wound and ulcerative lesions of the skin, monocomponent preparations containing at least 100,000 IU of vitamin A (for example, Aevit, fish oil concentrate, etc.) will be the best. For the treatment of wounds on the skin and mucous membranes, the best external preparation of vitamin A is an oily solution of carotene.

Vitamin A - instructions for use

Any preparations of vitamin A can be taken orally in the form of tablets, dragees, powders and solutions, injected intramuscularly or used externally in the form of applications, dressings, lotions, etc. Intramuscular administration of vitamin A is used only in hospitals in the treatment of severe beriberi, severe night blindness, as well as severe inflammatory diseases of the digestive tract, genitourinary and respiratory organs. Externally, vitamin A is used in the form of an oily solution to treat ulcers, inflammation, wounds, eczema, frostbite, burns and other skin lesions. Inside vitamin A is taken for preventive purposes and for the treatment of mild hypovitaminosis.

Inside, you need to take 3-5 tablets or tablets per day after meals. An oil solution of vitamin A is taken 10-20 drops three times a day after meals on a piece of black bread. The duration of the course of application ranges from 2 weeks to 4 months and depends on the purpose for which vitamin A is used. Long-term courses for at least one month. After a monthly intake of vitamin A, it is necessary to take a break for 2-3 months, after which the course can be repeated.

Intramuscularly, a solution of vitamin A is administered every other day for adults at 10,000 - 100,000 IU and for children at 5,000 - 10,000 IU. The course of treatment is 20 - 30 injections.

The maximum allowable single dose of vitamin A when taken orally and intramuscularly is 50,000 IU (15,000 mcg or 15 mg), and the daily dose is 100,000 IU (30,000 mcg or 30 mg).

Locally, an oil solution of vitamin A is used to treat various wounds and inflammations of the skin (ulcers, frostbite, burns, non-healing wounds, eczema, boils, pustules, etc.), applying it to a previously cleaned affected surface. The wound surface is simply lubricated with an oil solution of 5 - 6 times a day and cover with 1 - 2 layers of sterile gauze. If it is impossible to leave the wound open, then an ointment with vitamin A is applied to it and a sterile bandage is applied on top. With topical application of vitamin A, it is also mandatory to prescribe it orally in prophylactic dosages (5000 - 10,000 IU per day).