Not everyone knows what are the functions of vitamin A in the body and how it helps a child, a man and a woman, and who really needs it in injections. It is worth remembering that he is pricked only as directed by a doctor, as well as taken in a different form. Vitamin A helps stop skin flaking and does a lot more that will be beneficial even during pregnancy.

This article provides detailed introductory information on vitamin A and addresses a number of frequently asked questions related to its use, and the dosage is determined by the doctor, as well as the possibility of its use, because there are contraindications.

Vitamin A contraindications

Vitamin A is contraindicated:
- suffering from alcoholism;
- with liver diseases (cirrhosis, viral hepatitis, etc.);
- with renal failure;
- during pregnancy;
- Women who are breastfeeding.
In addition, vitamin A should be given with caution to the elderly and children.

Vitamin A for what it is useful and the body needs briefly and where it is contained

Vitamin A contributes to:
- improving visual acuity;
- maintaining skin tone;
- the development of bones and bone tissues;
- prevention of aging;
- wound healing;
- suppression of infections.
It is deservedly called the vitamin of health, beauty and youth.

Vitamin A is found in:
- red pepper;
- raspberries;
- carrots;
- parsley;
- fish liver and beef liver;
- butter;
- pumpkin;
- dill and green onions;
- citrus fruits;
- wild rose;
- egg yolk, etc.

Vitamin A for what it is needed in the body for women, adults, children

Vitamin A (retinol) improves immunity and protects against most colds and infectious diseases. With its deficiency, a person begins to see worse, especially at night, his skin becomes excessively dry, and his hair and nails brittle (which pretty much spoils women's nervous system). In addition, vitamin A increases the chance of successful conception and has a beneficial effect on the health of an already born child. It contributes to the proper formation of a growing organism, and prevents infection of the respiratory tract, gastrointestinal tract and genitourinary system.

Vitamin A for what is useful for the face, in ampoules, capsules and how to use, masks

Vitamin A or retinol is a universal remedy for the care of both dry and oily skin. In another article, read about. It is effective in the fight against acne, pimples and other rashes, as it eliminates foci of inflammation. In addition, the vitamin of this group has the ability to smooth wrinkles and discolor age spots, so that the skin acquires elasticity and a healthy color.

Retinol is available in capsules, ampoules, packaged in bottles, but for masks it is better to use it not in pure form, and combine with 1-2 tablespoons of sour cream, cottage cheese or honey. Additives allow you to dilute the vitamin, since it does not exist in nature in such a strong concentration, and enhance the healing effect of the mask due to other components.

Vitamin A for the face in its pure form, external use and for acne

Vitamin A has a beneficial effect on the skin and helps to get rid of acne. It will not be difficult to make a mask out of it - a clean face is wiped with a cotton swab dipped in a vitamin from a capsule or ampoule, diluted in half with vegetable oil, and after 15 minutes the mask is washed off. But do not rush to blindly follow these tips. Test your response to vitamin A by applying it to your wrist before having a cosmetic procedure. If there is reddening of the skin or itching, vitamin A is contraindicated for you or you need to make it less concentrated.

Vitamin A for the skin around the eyes, head, body

Vitamin A is undoubtedly good for the skin, but it can cause allergies and swelling, so before using it, you need to check your reaction to this substance. In order not to complain about swelling after applying a mask with vitamin A, you need to know the boundaries of its application. The area around the eyes - the upper and lower eyelids (to the bone), as well as the lips, are not affected by the mask. When applying a healing composition, you need to literally turn your face into a theatrical mask drawn in the pictures.

For the head and body, adding a few capsules or ampoules of vitamin A to the shower gel or shampoo will be beneficial, but this procedure is contraindicated for allergies and pregnancy.

Vitamin A for hair in shampoo

Vitamin A can be added to hair shampoo, but in order to achieve a positive result from this procedure, it is not necessary to wash off the foam from the shampoo immediately, but after 10-15 minutes. Vitamin A is popularly believed to prevent hair from turning gray.

Vitamin A and E content in foods and contained in which foods

Vitamins A and E are fat-soluble, meaning they do not dissolve in water. Vitamins of this group are found in the liver, eggs, milk, rose hips. Apart from vitamin A, vitamin E is abundant in sunflower oil, nuts, apples and greens.

Vitamin A oil solution what to use

Vitamin A is used internally and externally in cases where there is a lack of it in the body. Retinol is widely used to treat diseases of the eyes (xerophthalmia, retinitis pigmentosa) and skin (burns, frostbite, rashes). It is also prescribed for ulcers and various pathologies of the gastrointestinal tract.

What is Liquid Vitamin A for?

Most often, liquid vitamin A is used externally. It has a positive effect on the functioning of the endocrine glands, and is also one of the the best means to maintain skin tone.

Vitamin A for the growth of eyebrows, muscles, human eyelashes

Vitamin A is insoluble in water, but mixes well with castor oil. This property of the vitamin can be used to create a nutrient solution for eyebrows and eyelashes. To simplify the procedure for applying the resulting product for the growth of cilia and hair on the eyebrows, you can use a washed brush from the brush.

Vitamin A in balls, chocolate, Elevit, apples, berries

The course of treatment with vitamin A (in "balls" or the drug Elevit) should be followed by following the doctor's recommendations, and not advice from the Internet, no matter how tempting they may be. Chemistry is chemistry. You can also saturate your body with vitamin A at the expense of natural gifts - apples and berries, as well as processed foods, for example, butter, cream, fish oil or chocolate.

Content

Vitamin A is not just in the first place in the general alphabetical list of vitamins: it is involved in almost all the main functions of the body, improves vision, strengthens the immune system. Vitamin A is also important for the skin. Let's find out what functions vitamin A performs, how to take it and what are the contraindications to taking it.

What is vitamin A good for the body

Vitamin A regulates the process of protein production by the body, contributes to the normalization of metabolism, strengthens the immune system, effectively resists viral infections, and helps with wound healing. In addition, it makes the skin of women and men elastic, smooth, relieves skin diseases. Retinol is also useful for vision, so people who spend a lot of time in front of the screen should include it in their diet. For example, a product such as carrots will protect the mucous membrane of the eye from drying out and relieve you of the feeling of "sand" in the eyes. And retinol will help you see better at night.

It must be present in the diet of infants and older children, because the components of the vitamin play an important role in the formation of bones, joints and teeth, accelerating cell growth. Retinol also has a positive effect on the functioning of the respiratory organs, digestive systems Therefore, for smokers, vitamin A is of particular importance.

For Women's Health

Retinol is of great importance for women. The breast, which consists primarily of adipose tissue, is highly dependent on the balance of fat-soluble vitamins. One of them is retinol. The work of the cells responsible for lactation is regulated by chemical processes occurring in the mammary glands. Numerous studies have proven that lactating and pregnant women need to take many additional vitamins, including retinol.

What vitamin A helps for is for the spectacular appearance of a woman. Retinol is directly involved in the normalization of the lipid balance of the body. This component improves the condition of hair, nails, skin, improves vision and strengthens the immune system. Retinol is an ingredient in professional skin care creams - it makes it supple, firm, smoothes fine wrinkles. Retinol can be a great alternative to many beauty products. At least, the reviews on the use of vitamin A for cosmetic purposes are entirely positive.

With vitamin A deficiency female body girls lose weight, have problematic dry skin, they are worried about bouts of depression, nausea, sleep problems. The mucous membrane of the eyes with a deficiency of retinol is not sufficiently moisturized, the eyes hurt. Subsequently, the development of cataracts is possible. A lack of retinol can make it difficult for a woman to get pregnant, and the gestation process will be difficult. The fetus will gain weight slowly, in the worst case, birth defects are possible. Finally, gynecological diseases may develop: cervical erosion, leukoplakia.

For kids

Vitamin deficiency in a child's body can lead to progressive blindness, conjunctivitis, reduced resistance to infectious (including colds) diseases, their frequent complications in the form of pneumonia or bronchitis, growth retardation, diseases of the digestive tract. A balanced diet and regular intake of vitamin A will help the body cope with such ailments. Retinol is good for the teeth and bones of newborns and young children - it accelerates their growth.

For weight loss

Vitamin A intake does not directly affect weight loss. On the other hand, experts recommend consuming the required dose of vitamin A orally for people involved in sports or fitness. Retinol speeds up metabolism, increases stamina and helps the body recover much faster from workout to workout. That is, you get the opportunity to practice more often and with maximum efficiency. And effective training will help to achieve quick results in losing weight, after which - to maintain the desired figure.

Why is vitamin A useful in cosmetology

The benefits of vitamin A are not only in healing the body from the inside, but also in a positive effect on the condition of the skin, nails, and hair. The widespread use of retinol by cosmetologists seems logical. The beneficial properties of vitamin A are known to millions of women who are trying to make their appearance flawless and use it both for the skin of the face and for the heels (for example, to heal cracks). Let's learn about the areas and features of the use of retinol in cosmetology.

Liquid vitamin for the face

Retinol has excellent efficacy in the treatment of various skin ailments, improves skin condition. If vitamin A is not enough in the body, wrinkles appear, the skin becomes dry, and the face looks unhealthy. Liquid retinol is used to treat:

• Chronic form of dermatosis.
• Psoriasis.
• Acne.
• Furunculosis.
• Psoriasis.
• seborrheic eczema.
• Inflammation of the oral mucosa.

Retinol has antioxidant properties, thanks to which the skin of the face becomes more resistant to sunlight and other adverse environmental factors. That is, liquid vitamin A keeps you young and makes you more attractive. This substance, included in the composition of masks, helps smooth wrinkles in a natural way, improve blood circulation, and natural skin regeneration. Beauticians claim that retinol is a great alternative to much more expensive cosmetic products, surpassing them in terms of effectiveness.

For eyelids and eyelashes

If you want to become the owner of beautiful, long, elastic and, most importantly, natural eyelashes, be sure to use products containing vitamin A. Retinol is needed for the synthesis of keratin, a substance that accelerates the growth of eyelashes, helping them recover faster from damage, increasing their elasticity. We offer an effective cosmetic recipe: mix vitamin A with castor oil (proportion 1:3) and apply the resulting mixture on the eyelashes every evening for 3-5 minutes. After this time, gently wipe them with a sponge.

The benefits of hair masks

Enrichment of hair with retinol, included in the masks, helps to improve their condition. Thanks to retinol, the curls are strengthened, become elastic, smooth, look healthy, alive. With a deficiency of this substance - brittle, dry, often fall out. To strengthen curls, you need to rub retinol and other useful vitamins fingertips into the roots of the hair or apply to their ends. Remember that masks should be applied to washed, slightly damp curls. The cap will ensure more effective absorption of useful components.

For hands and nails

Devoting a lot of time to facial skin care, the fair sex often make the mistake of forgetting about the skin of their hands. After all, it is also exposed to external influences (sudden temperature fluctuations, ultraviolet radiation, household chemicals), from which it begins to peel off, dry out, crack, and look unkempt. Diet, work, and the general condition of the body have a great influence on the appearance of the skin of the hands.

Retinol is a natural ingredient that helps to cope with the above problems. Note that it also has a positive effect on the nail plates, strengthening them, making them smoother, accelerating growth and preventing delamination. Eat more fresh vegetables that are rich in retinol, and foods that are a source of animal proteins - dairy products, sea fish. Proteins provide better absorption of retinol by the body. It is noteworthy that the rate of nail growth in vegetarians is very low.

We offer an effective method of hand skin care. Purchase oil solutions of vitamins A, E at the pharmacy and rub them in regularly. In parallel, take retinol in capsules or tablets (not exceeding the allowable dosage). Beauticians recommend another way, based on the enrichment of regular hand cream with retinol. It is not difficult to do this: just pour the hand cream into a clean empty container, add the oil solution there, mix. Use like a normal cream.

How to take vitamin A capsules correctly

When taking vitamin A capsules, it is important not to violate the dosage prescribed for you, because an excess of this substance in the body can be no less harmful than a lack of retinol. The average daily requirement for an adult in retinol is 1 mg, for a child - from 400 to 800 mcg. Note that vitamin A is available in capsules containing 33,000, 50,000 or 100,000 IU (international units).

Interestingly, simply consuming the right amount of capsules is not enough to eliminate the body's deficiency in vitamin A. You also need to know exactly how to use retinol. So, the capsules should be drunk 2 times a day - in the morning and in the evening, moreover, exactly 10 minutes after the end of the meal. The reason is that just after such a time, the stomach extracts components from food that promote the absorption of vitamin A. Without them, retinol will not be effectively absorbed.

Contraindications to the use of retinol

Retinol, according to the instructions, is not recommended if you have been diagnosed with gallstone disease, pancreatitis, hypersensitivity to the substance. A contraindication is also the period of pregnancy, especially the first 3 months after fertilization. You should be careful in chronic diseases of the heart, kidneys. Other contraindications for taking retinol: cirrhosis of the liver, hepatitis. Be sure to observe the daily norm for children, the elderly, nursing mothers.

Interaction of vitamin A with other substances

Vitamin E is known to protect retinol from rapid oxidation in the intestines and body tissues. That is, if your diet does not have enough foods containing vitamin E, the body will not effectively absorb retinol. The solution is a complex intake of both vitamins. Zinc deficiency also interferes with the conversion of vitamin A into active ingredients. Moreover, there is an inverse relationship. That is, these substances are interconnected.

Mineral oils are able to dissolve fat-soluble components: then vitamin A passes through the intestines, but is not absorbed by its walls. Therefore, the regular use of mineral oils leads to a deficiency of retinol in the body, even if there is plenty of this substance in the products you consume. The way out will be a temporary rejection of mineral oils.

Finally, it should be noted that for good absorption of retinol, the presence of a sufficient amount of fats and proteins in the daily diet is mandatory. The body normally extracts vitamin A dissolved in dietary fats. It should also be remembered that while taking retinol, it is necessary to exclude from your diet. alcoholic drinks. Neglect of this rule is fraught with the likelihood of liver damage.

Why is vitamin A good for women?

Retinol is necessary at all stages of life for good health and full functioning of the body. Benefits of vitamin A for women:

organism	Why do you need vitamin A
Pregnancy and breastfeeding	Retinol is essential for the normal development of the embryo. Participates in the synthesis of adipose tissue, normalizes the functioning of the mammary glands. Accelerates regeneration processes after childbirth
For weight loss	Vitamin A is especially useful for losing weight. It speeds up metabolic processes, protects cells from damage, and promotes speedy recovery. Makes the body more resilient, so weight loss workouts are carried out with maximum efficiency
For skin	Makes a woman's skin more elastic, accelerates the healing of cuts, rashes, fights dryness. Evens complexion, provides nutrition and hydration to the skin, excellent prevention of premature wrinkles. Retinol is involved in collagen synthesis
For hair	Normalizes the activity of the sebaceous glands, prevents the appearance of dandruff and dryness of the scalp. Makes hair more elastic and shiny, accelerates their growth. Protects against UV rays
For nails	Effectively fights delamination, promotes the growth of nail plates, eliminates dryness and ribbing of the nail, makes it more durable

The daily dosage for women is 2300-2500 IU. In diseases that are caused by vitamin A deficiency, the dosage can be increased up to 10,000 IU. The maximum dose for pregnant women is 6000 IU. Do not overuse retinol. It can cause birth defects in the fetus.

Natural sources of vitamin A

There are 2 forms of the vitamin:

• Active (retinol) - found in products of animal origin, well absorbed by the body. Sources: liver, meat, heart, fish. As well as seafood, dairy products, eggs.
• Passive (beta-carotene) - when ingested, it is converted into active, but absorbed more slowly. Sources: carrots, broccoli, persimmons, spinach, pumpkin. And also carrots bell pepper and tomatoes.

In addition to an unbalanced diet, hypovitaminosis may appear due to chronic diseases of the gastrointestinal tract (GIT), metabolic disorders, and taking medications. Signs of a retinol deficiency:

• Visual impairment (night blindness, conjunctivitis, reduced clarity).
• Dry skin, the appearance of sores, rashes.
• Decreased performance, chronic fatigue.
• Deterioration of immunity - a person gets sick more often and longer.
• The condition of hair and nails worsens.
• Libido decreases, the work of the reproductive system is disrupted.
• Decreased appetite.

Taking pharmaceutical drugs

The human body needs retinol all the time. In small amounts, it can accumulate in internal organs. This reserve is not enough for the normal functioning of all systems. Additional intake of vitamin preparations is recommended in the following cases:

• Seasonal hypovitaminosis.
• The period of rehabilitation after injuries, diseases.
• Change of scenery, stressful situations.
• During pregnancy and lactation (if indicated).
• For the complex treatment of diseases of the skin, hair and reproductive system.

The most popular vitamin A preparations

A drug	Why is a drug with vitamin A useful for women?	Reception features
Retinol Acetate	Vitamin A in drops, available in ampoules or vials. It is mainly used to enrich cosmetics, but can also be added to food.	Add 1-2 drops to food. Better taken with fatty foods
AEvit	The composition of the drug includes vitamins A and in equal proportions. Available in light yellow jelly capsules	Take 1 capsule 2 times a day with meals
AEcol	Vitamins in capsules, contain tocopherol and retinol. Well absorbed by the body	Drink 1 capsule 2 times a day before meals
Multivitamins	Retinol is part of most vitamin complexes: Vitrum, Multi-Tabs, Duovit, Pikovit, Supradin, etc.	If a person takes a multivitamin, he should not drink drugs with retinol at the same time

Features of taking vitamins

Vitamins are recommended to be taken during or after meals. It is preferable to drink clean water. The best period for taking drugs is the first half of the day, since retinol has a tonic effect on the body. In most cases, drugs with retinol are well accepted by the body, but there are also contraindications:

• Hypervitaminosis.
• Cholelithiasis.
• Pancreatitis, pyelonephritis.
• Hepatitis, cirrhosis of the liver.
• Chronic heart disease.
• First trimester of pregnancy.
• Individual sensitivity to components.

For normal absorption, retinol is best taken with vitamin E - it protects vitamin A from rapid oxidation. Zinc is also needed, which converts retinol to its active form. The main obstacle to the absorption of fat-soluble vitamins is mineral oils - they must be excluded from the diet.

Questions such as the benefits and harms of retinol are still being investigated by scientists. An overdose of vitamin A can cause intoxication of the body. High doses are especially dangerous for pregnant women. They have a teratogenic effect on the fetus and can cause developmental pathologies. Hypervitaminosis is manifested by the following symptoms:

• Weakness, nausea, vomiting.
• Yellowing of the skin.
• Allergic skin rashes, itching.
• Pain in the abdomen and joints.
• Strong sweating.
• Peeling of the skin, the appearance of jamming in the corners of the mouth.

If such symptoms appear, the drug should be stopped and consult a doctor.

Healthy Vitamin A Beauty Recipes

Mask for the face. To prepare it, you will need an ampoule of retinol and tocopherol, a tablespoon of almond oil, 1 yolk. All ingredients must be mixed and applied with a brush to the skin. Keep for 20-30 minutes and rinse with warm water and cleanser.

Hair Mask. Ingredients: a tablespoon of castor and burdock oil, 1 yolk, 10 drops of vitamin A and 10 drops of vitamin E. Mix all components well, apply to the roots and along the entire length of the hair. Wrap your head in a plastic cap and a towel and keep it for 1-1.5 hours. Wash off with warm water and shampoo.

Expert advice! Vitamin A can be enriched with shampoos, masks, creams and other ready-made cosmetics. Before use, you need to do an allergy test by applying the composition to the wrist or bend of the elbow. If redness or itching does not appear within 5-10 minutes, the composition can be used.

What do vitamins A and E need for a woman's body? Recipes useful masks and advice from beauticians in the video below.

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

Thanks

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 Cyrillic letter 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.

In principle, different forms of vitamin A perform different functions 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 the supply of vitamin A 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 entrenched, 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

Man in various age periods should consume different amounts of vitamin A per day. Daily intake of vitamin A for children different ages regardless of gender:

• 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 a person needs 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 the following animal products:

• 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 vegetables and fruits of red-orange color. 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 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) can lead to congenital malformations 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 an effective method of preventing 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 and inflammatory diseases of the respiratory system, 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, persistent 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 growth retardation, 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 pregnancy a complex preparation "Aevit", 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 beriberi A or 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 urinary organs, as well as infectious-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).

International name - Vitamin A, in the form of a dietary supplement is also called retinol.

A fat-soluble vitamin, an essential component for healthy growth, bone and tooth tissue formation, and cell structure. It is of great importance for night vision, it is necessary to protect against infections of the tissues of the respiratory, digestive and urinary tracts. Responsible for the beauty and youthfulness of the skin, the health of hair and nails, visual acuity. Vitamin A is absorbed in the body in the form of retinol, which is found in liver, fish oil, egg yolk, dairy products and added to margarine. Carotene, which is converted into retinol in the body, is found in many fruits and vegetables.

Discovery history

The first prerequisites for the discovery of Vitamin A and the consequences of its deficiency appeared as early as 1819, when the French physiologist and psychologist Magendie noticed that dogs that receive poor nutrition are more likely to get corneal ulcers and have a higher mortality rate.

In 1912, British biochemist Frederick Gowland Hopkins discovered hitherto unknown substances in milk that did not look like fats, carbohydrates, or proteins. Upon closer examination, it turned out that they contributed to the growth of laboratory mice. Hopkins received the Nobel Prize in 1929 for his discovery. In 1917, Elmer McCollum, Lafayette Mendel, and Thomas Burr Osborne also saw similar substances when studying the role of dietary fats. In 1918, these "additional substances" were found to be fat-soluble, and in 1920 they were finally given the name Vitamin A.

Foods rich in vitamin A

Estimated availability in 100 g of product

Daily requirement for vitamin A

Recommendations for daily intake of vitamin A are based on the amount needed to provide a supply of retinol for several months in advance. This reserve maintains the normal functioning of the body and ensures the healthy functioning of the reproductive system, immunity, vision and gene activity.

In 1993, the European Scientific Committee on Nutrition published data on the recommended intake of vitamin A:

Many European nutritional committees, such as the German Nutrition Society (DGE), recommend 0.8 mg (800 mcg) of vitamin A (retinol) for women and 1 mg (1000 mcg) for men per day. Since vitamin A plays a significant role in the normal development of the embryo and newborn, pregnant women are advised to take 1.1 mg of vitamin A starting from the 4th month of pregnancy. Women who are breastfeeding should receive 1.5 mg of vitamin A per day.

In 2015, the European Food Safety Authority (EFSA) established that the daily intake of vitamin A should be 750 mcg for men, 650 mcg for women, for newborns and children - from 250 to 750 mcg of the vitamin per day, taking into account age . During pregnancy and lactation, the additional amount of the vitamin that should be ingested due to the accumulation of retinol in the tissues of the fetus and mother, as well as the intake of retinol in breast milk, was indicated at 700 and 1,300 mcg per day, respectively.

In 2001, the American Food and Nutrition Council also set the recommended intake for vitamin A:

As we can see, although the amount varies according to different organizations, the approximate daily intake of vitamin A remains at the same level.

The need for vitamin A increases with:

1. 1 weight gain;
2. 2 strenuous physical labor;
3. 3 work in night shifts;
4. 4 participation in sports competitions;
5. 5 stressful situations;
6. 6 work in conditions of improper lighting;
7. 7 additional eye strain from monitors;
8. 8 pregnancy, breastfeeding;
9. 9 problems with the gastrointestinal tract;
10. 10 SARS.

Physical and chemical properties

Vitamin A is a fat-soluble vitamin that is part of a group of molecules with a similar structure - retinoids - and occurs in several chemical forms: aldehydes (retinal), alcohol (retinol) and acid (retinoic acid). In animal products, the most abundant form of vitamin A is an ester, primarily retinyl palmitate, which is synthesized to retinol in the small intestine. Provitamins - biochemical precursors of vitamin A - are present in plant products, they are components of the carotenoids group. Carotenoids are organic pigments found naturally in plant chromoplasts. Less than 10% of 563 known to science carotenoids can be synthesized into vitamin A in the body.

Vitamin A is a fat-soluble vitamin. This is the name of a group of vitamins, for the assimilation of which the body needs the intake of dietary fats, oils or lipids. These include, for example, cooking oils, nuts, fish, meat, avocados.

Vitamin A dietary supplements are often available as oil-filled capsules to ensure that the vitamin is fully absorbed by the body. People who don't eat enough dietary fat are more likely to be deficient in fat-soluble vitamins. Similar problems can occur in people with poor absorption of fats. Fortunately, fat-soluble vitamins naturally occur naturally in foods that contain fat. Thus, with a good diet, the lack of such vitamins is rare.

In order for vitamin A or carotene to enter the bloodstream in the small intestine, it is necessary that they, however, like other fat-soluble vitamins, are combined with bile. If the food at this moment contains little fat, then little bile is secreted, which leads to malabsorption and loss of up to 90 percent of carotene and vitamin A with feces.

Approximately 30% of beta-carotene is absorbed from plant foods, about half of beta-carotene is converted into vitamin A. From 6 mg of carotene, 1 mg of vitamin A is formed in the body, so the conversion ratio of the amount of carotene to the amount of vitamin A is 1:6.

Useful properties of vitamin A

Vitamin A performs several functions in the body. The most famous is its effect on vision. Retinyl ester is transported to the retina, which is located inside the eye, where it is processed into a substance called 11-cis-retinal. Further, 11-cis-retinal is in the rods (one of the photoreceptors), where it combines with the protein opsin and forms the visual pigment "rhodopsin". Rods containing rhodopsin can detect even very small amounts of light, making them essential for night vision. The absorption of a photon of light catalyzes the transformation of 11-cis-retinal back to all-trans-retinal and results in its release from the protein. This sets off a chain of events leading to the generation of an electrochemical signal to the optic nerve, which is processed and interpreted by the brain. Lack of retinol available to the retina leads to impaired dark adaptation, known as night blindness.

Vitamin A in the form of retinoic acid plays an important role in the regulation of gene expression. Once retinol is taken up by the cell, it can be oxidized to retinal, which is oxidized to retinoic acid. Retinoic acid is a very powerful molecule that binds to various nuclear receptors to initiate or inhibit gene expression. Through the regulation of the expression of specific genes, retinoic acid plays an important role in cell differentiation, one of the most important physiological functions.

Vitamin A is needed for the normal functioning of the immune system. Retinol and its metabolites are needed to maintain the integrity and function of skin cells and mucous membranes (respiratory, digestive and urinary systems). These tissues serve as a barrier and are the body's first line of defense against infections. Vitamin A plays a central role in the development and differentiation of white blood cells, lymphocytes, which are key agents in the immune system's response.

Vitamin A is indispensable for embryonic development, being directly involved in the growth of limbs, the formation of the heart, eyes and ears of the fetus. In addition to this, retinoic acid affects the expression of the gene responsible for growth hormone. Both deficiency and excess of vitamin A can cause birth defects.

Vitamin A is used for the normal development of stem cells into red blood cells. In addition, vitamin A probably improves the mobilization of iron from reserves in the body, directing it to the developing red blood cell. There, iron is incorporated into hemoglobin, the oxygen carrier in red blood cells. Vitamin A metabolism is thought to interact with zinc and iron in several ways. Zinc deficiency can lead to a decrease in the amount of transported retinol, a decrease in the release of retinol in the liver, and a decrease in the conversion of retinol to the retina. Vitamin A supplements have a beneficial effect on iron deficiency (anemia) and improve iron absorption in children and pregnant women. The combination of vitamin A and iron appears to treat anemia more effectively than supplemental iron or vitamin A alone.

Recent studies have shown that vitamin A, carotenoids, and provitamin A carotenoids may be effective antioxidants in preventing heart disease. The antioxidant activity of vitamin A and carotenoids is provided by the hydrophobic chain of polyene units, which can quench singlet oxygen (molecular oxygen with higher activity), neutralize thiyl radicals, and stabilize peroxyl radicals. In short, the longer the polyene chain, the higher the stability of the peroxyl radical. Due to their structure, vitamin A and carotenoids can be oxidized with increasing O2 tension and thus are the most effective antioxidants at low oxygen tensions, which are characteristic of the physiological levels found in tissues. Overall, epidemiological evidence suggests that vitamin A and carotenoids are important dietary factors in reducing the incidence of heart disease.

The European Food Safety Authority (EFSA), which provides scientific advice to policy makers, has confirmed that the following health benefits have been seen with vitamin A intake:

• normal cell division;
• normal development and functioning of the immune system;
• maintaining the normal condition of the skin and mucous membranes;
• maintaining vision;
• normal iron metabolism.

Vitamin A has a high compatibility with vitamins C and E and the minerals iron and zinc. Vitamins C and E protect vitamin A from oxidation. Vitamin E increases the absorption of vitamin A, but only in cases where vitamin E is consumed in a small amount. A high content of vitamin E in the diet, in turn, impairs the absorption of vitamin A. Zinc helps the absorption of vitamin A, taking part in its conversion to retinol. Vitamin A enhances the absorption of iron and influences the utilization of the iron reserve present in the liver.

Vitamin A also pairs well with vitamins D and K2, magnesium, and dietary fat. Vitamins A, D and K2 work synergistically to support immune health, promote adequate growth, maintain bone and dental health, and protect soft tissues from calcification. Magnesium is essential for the production of all proteins, including those that interact with vitamins A and D. Many of the proteins involved in vitamin A metabolism and the receptors for both vitamins A and D only function properly in the presence of zinc.

Vitamins A and D also work together to regulate the production of certain vitamin dependent proteins. Once vitamin K activates these proteins, they help mineralize bones and teeth, protect arteries and other soft tissues from abnormal calcification, and protect against cell death.

Foods containing vitamin A are best consumed with foods that contain “healthy” fat. For example, spinach, which contains a high content of vitamin A and lutein, is recommended to be combined with avocado. The same goes for lettuce and carrots, which pair well with avocados in salads. As a rule, animal products rich in vitamin A already contain a certain amount of fat, sufficient for its normal absorption. As for vegetables and fruits, it is recommended to add a small amount vegetable oil in a salad or freshly squeezed juice - this way we will be sure that the body will receive the necessary vitamin in full.

It is worth noting that the best source of vitamin A in particular, as well as other useful substances, is a balanced diet and natural products, and not dietary supplements. When using vitamins in medicinal form, it is very easy to make a mistake with the dosage and get more than the body needs. And an excess of one or another vitamin or mineral in the body can have very serious consequences. The risk of developing oncological diseases may increase, the general condition of the body may worsen, metabolism and the functioning of organ systems may be disturbed. Therefore, the use of vitamins in tablets should be carried out only if necessary and after consulting a doctor.

Application in medicine

Intake of a large amount of vitamin A is prescribed in such cases:

• with vitamin A deficiency, which can occur in people with protein deficiency, diabetes, an overactive thyroid gland, fever, liver disease, cystic fibrosis, or an inherited disorder called abelatipoproteinemia.
• in breast cancer. Premenopausal women with a family history of breast cancer who consume high levels of vitamin A in their diet are thought to reduce their risk of developing breast cancer. It is not known whether taking vitamin A as a dietary supplement has a similar effect.
• with cataracts. Studies show that a high intake of vitamin A in the diet leads to a reduced risk of developing cataracts.
• with diarrhea caused by HIV. Taking vitamin A along with conventional medications appears to reduce the risk of death from diarrhea in HIV-infected children with vitamin A deficiency.
• with malaria. Taking vitamin A by mouth reduces the symptoms of malaria in children under 3 years of age in areas where malaria is common.
• with measles. Taking vitamin A by mouth reduces the risk of complications or death from measles in children who have measles and are deficient in vitamin A.
• with precancerous lesions in the mouth (oral leukoplakia). Research shows that taking vitamin A can help treat precancerous lesions in the mouth.
• in recovery after laser eye surgery. Taking vitamin A orally along with vitamin E improves healing after laser eye surgery.
• with complications after pregnancy. Taking vitamin A reduces the risk of diarrhea and fever after pregnancy in malnourished women.
• with complications during pregnancy. Oral vitamin A supplementation reduces the risk of death and night blindness during pregnancy in malnourished women.
• in eye diseases affecting the retina (retinitis pigmentosa). Studies show that vitamin A supplementation can slow the progression of eye diseases that cause damage to the retina.

The pharmacological form of vitamin A can be different. In medicine, it is found in the form of dragees, drops for oral administration, drops for oral administration in oil form, capsules, oily solution for intramuscular administration, oily solution for oral administration, in the form of coated tablets. Vitamin A is taken for prevention and for medicinal purposes, as a rule, 10-15 minutes after eating. Oil solutions are taken in case of malabsorption in the gastrointestinal tract or in severe illness. In cases where long-term treatment is necessary, the solution for intramuscular injection is combined with capsules. In pharmacology, the amount of vitamin A is often indicated in International Units. With mild to moderate beriberi, adults are prescribed 33 thousand International Units per day; with hemeralopia, xerophthalmia - 50-100 thousand IU / day; children - 1-5 thousand IU / day, depending on age; for skin diseases in adults - 50-100 thousand IU / day; children - 5-20 thousand IU / day.

Traditional medicine advises the use of vitamin A as a remedy for flaky and unhealthy skin. To do this, it is recommended to consume fish oil, liver, butter and eggs, as well as vegetables rich in vitamin A - pumpkin, apricot, carrots. good remedy make up for the deficiency is freshly squeezed carrot juice with the addition of cream or vegetable oil. Another folk remedy obtaining a vitamin is considered a decoction of tubers high - it is used as a tonic, tonic and antirheumatic agent. Also a valuable source of vitamin A, as well as other useful substances, are flax seeds, which are consumed orally and as part of external masks, ointments and decoctions. According to some reports, a high amount of vitamin A is contained in the tops of carrots, even more than in the fruit itself. It can be used in cooking, as well as making a decoction, which is used internally as a course for a month.

Latest scientific research on vitamin A:

Researchers at the Case Western Reserve University School of Medicine have discovered that an uncontrolled metabolism of vitamin A in the gut can cause dangerous inflammation. The discovery establishes a link between dietary composition and inflammatory diseases such as Crohn's disease and irritable bowel syndrome.

Researchers have found a branch point in the vitamin A metabolic pathway that depends on a specific protein called ISX. The beginning of the journey is beta-carotene, a pigmented, highly nutritious substance, thanks to which the color of sweet potatoes and carrots is formed. Beta-carotene is converted to vitamin A in the digestive tract. From there, the largest proportion of vitamin A is delivered to other tissues, providing good vision and other important functions. When studying mice that had had ISX removed, scientists noticed that this protein helps the body balance this process. Protein helps the small intestine determine how much beta-carotene it needs to meet the body's need for vitamin A. Immune cells rely on this control mechanism to properly respond to foods entering the small intestine. This provides an effective barrier against potential food hazards. Researchers have found that when ISX is absent, immune system cells in the digestive tract overreact to the beta-carotene-rich diet. Their results prove that ISX is the main link between what we eat and gut immunity. The scientists concluded that removing the ISX protein speeds up the expression of the gene that converts beta-carotene to vitamin A by 200 times. Because of this, ISX-deleted mice received an excess of vitamin A and began to convert it into retinoic acid, a molecule that regulates the activity of many genes, including those that form immunity. This caused localized inflammation as immune cells filled the area in the gut between the stomach and colon and began to multiply. This severe inflammation spread to the pancreas and caused the mice to become immunodeficient.

A recent study shows that vitamin A increases the activity of insulin-producing β-cells. Scientists have found that insulin-producing beta cells have a high number of receptors on their surface that are sensitive to vitamin A. Researchers believe that the reason for this is that vitamin A plays an important role in the development of beta cells in the early stages of life. , as well as for correct and functioning during the rest of life, especially during pathophysiological conditions - that is, with certain inflammatory diseases.

To study the importance of vitamin A in diabetes, the researchers worked with insulin cells from mice, healthy people, and people with type 2 diabetes. The scientists fragmentarily blocked the receptors and gave the patients some sugar. They saw that the cells' ability to secrete insulin was deteriorating. The same trend could be observed when comparing insulin cells from donors with type 2 diabetes. The cells of patients with type 2 diabetes were less able to produce insulin compared to those of people without diabetes. Scientists have also discovered that the resistance of beta cells to inflammation is reduced in the absence of vitamin A. When it is completely absent, the cells die. This study may also be relevant for some types of type 1 diabetes, where beta cells are poorly developed in the early stages of life. “As it became clear after research with animals, newborn mice need vitamin A for the full development of their beta cells. We are pretty sure that the same thing happens in humans. Children, in their diet, need to receive required amount vitamin A,” said Albert Salehi, senior research fellow at the Center for Diabetes at Lund University in Sweden.

Scientists at the University of Lund in Sweden have discovered a previously unexplored effect of vitamin A on human embryonic development. Their research demonstrates that vitamin A has an effect on the formation of blood cells. The signaling molecule known as retinoic acid is a vitamin A derivative that helps determine how different types tissues in the growing fetus.

An unprecedented study by Prof. Niels-Bjarn Woods' laboratory at the Lund Stam Cell Center in Sweden showed the effect of retinoic acid on the development of red blood cells, white blood cells and platelets from stem cells. Under laboratory conditions, stem cells were influenced by certain signaling molecules, transforming into hematopoietic cells. Scientists have noticed that high levels of retinoic acid rapidly lower the number of blood cells produced. The decrease in retinoic acid, in turn, increased the production of blood cells by 300%. Despite the fact that vitamin A is needed for the normal course of pregnancy, it has been found that an excess of vitamin A harms the embryo, introducing the risk of developing a malformation or stopping the pregnancy. In view of this, pregnant women are strongly advised to control the intake of foods containing a large amount of vitamin A in the form of retinoids, such as, for example, liver. “The results of our study show that vitamin A in in large numbers negatively affects hematopoiesis. This suggests that pregnant women should additionally avoid excessive intake of vitamin A,” says Niels-Bjarn Woods.

This is one of the main components that provide a healthy and toned skin. With the intake of a sufficient amount of vitamin, you can forget about such problems as skin laxity, age spots, acne, acne, dryness.

Vitamin A in its pure, concentrated form can be easily found in pharmacies, in the form of capsules, oil solutions and ampoules. It is worth remembering that this is a fairly active component, so it should be used with caution, and preferably after 35 years. Cosmetologists advise making masks containing vitamin A during the cold season and once a month. If there are contraindications to the use of pharmacy vitamin A as part of masks, you can replace it with natural products that are rich in this vitamin - viburnum, parsley, spinach, egg yolks, dairy products, pumpkin, carrots, fish oil, algae.

There are many recipes for masks with vitamin A. They often contain fat-containing substances - olive oil, fat sour cream, burdock oil. Vitamin A (oil solution and retinol acetate) has good compatibility with aloe juice, oatmeal and honey. To eliminate mimic wrinkles and bruises under the eyes, you can use a mixture of vitamin A and any vegetable oil, or Aevit, which already contains both vitamin A and vitamin E. Good preventive and remedy from acne - a mask with ground lentils, vitamin A in an ampoule or a small amount of zinc ointment, applied 2 times a month. In the presence of allergic reactions, open wounds and skin lesions, any of its diseases should refrain from using such masks.

Vitamin A is also good for nail health when mixed with other ingredients. For example, you can prepare a hand mask with liquid vitamins A, B, and D, oily hand cream, coconut oil, lemon juice, and a drop of iodine. This mixture should be applied to the skin of the hands and nail plates, massaged for 20 minutes and left to be absorbed. Regular implementation of this procedure will improve the condition of nails and hands.

The impact of vitamin A on the health and beauty of hair should not be underestimated. It can be added to shampoos (immediately before each procedure, in order to avoid oxidation of the substance when added to a whole package of shampoo), to masks - to increase shine, softness and strength of the hair. As in face masks, vitamin A is recommended to be combined with other ingredients - vitamin E, various oils, decoctions (chamomile, horsetail), starch (for softness), mustard or pepper (to accelerate hair growth). These products should be used with caution for those who are allergic to pharmacy vitamin A and for those whose hair is prone to increased oiliness.

Vitamin A in animal, crop and industry

Found in green grass, alfalfa, and some fish oils, vitamin A, otherwise known as retinol, is one of the nutrients essential for poultry health. Vitamin A deficiency leads to poor plumage along with weakness, eye and beak problems, up to and including damage. Another important factor for production is that lack of vitamin A can slow down growth.

Vitamin A has a relatively short shelf life and, as a result, dry foods stored for extended periods of time may not contain sufficient amounts of the vitamin. After illness or stress, the immune system of birds is very weak. By adding a short course of vitamin A to feed or water, further illness can be prevented, as without sufficient vitamin A, birds are susceptible to a number of harmful pathogens.

Vitamin A is also essential for the healthy growth of mammals, to maintain a good appetite, coat condition and immunity.

• it is the first vitamin discovered by man;
• polar bear liver is so rich in vitamin A that eating a whole liver can be fatal to humans;
• approximately 259 to 500 million children lose their sight every year due to vitamin A deficiency;
• in cosmetics, vitamin A is most often found under the names retinol acetate, retinyl linoleate and retinyl palmitate;
• rice fortified with vitamin A, developed about 15 years ago, could prevent hundreds of thousands of cases of blindness in children. But due to concerns about genetically modified products, it was never put into production.

Dangerous properties of vitamin A, its contraindications and warnings

Vitamin A is sufficiently resistant to high temperatures, but is destroyed by direct sunlight. Therefore, it is necessary to store vitamin-rich foods, as well as medical nutritional supplements, in a dark place.

Signs of Vitamin A Deficiency

Vitamin A deficiency usually results from inadequate intake of foods high in vitamin A, beta-carotene, or other provitamin A carotenoids; which are metabolized into vitamin A in the body. In addition to dietary problems, excess alcohol intake and malabsorption can be the cause of vitamin A deficiency.

The earliest sign of vitamin A deficiency is blurred vision in the dark, or night blindness. Severe or prolonged vitamin A deficiency causes changes in corneal cells that eventually lead to corneal ulcers. Vitamin A deficiency among children in developing countries is the leading cause of blindness.

Vitamin A deficiency is also associated with immunodeficiency, decreasing the ability to fight infections. Even children with mild vitamin A deficiency have a higher incidence of respiratory disease and diarrhea, as well as a higher mortality rate from infectious diseases (especially measles) compared to children with adequate vitamin A intake. In addition, vitamin A deficiency can cause impaired growth and bone formation in children and adolescents. In smokers, vitamin A deficiency can contribute to chronic obstructive pulmonary disease (COPD) and emphysema, both of which are thought to increase the risk of lung cancer.

Signs of Too Much Vitamin A

Acute vitamin A hypervitaminosis caused by very high doses of retinol, which is rapidly absorbed and slowly excreted from the body, is relatively rare. Symptoms include nausea, headache, fatigue, loss of appetite, dizziness, dry skin, and swelling of the brain. There are studies that prove that prolonged excess of vitamin A in the body can lead to the development of osteoporosis. Some synthetic retinol derivatives (eg, tretinate, isotretinoin, tretinoin) may cause fetal defects and therefore should not be used during pregnancy or when trying to conceive. In such cases, beta-carotene is considered the safest source of vitamin A.

Results from the Beta-Carotene and Retinol Efficacy Study (CARET) suggest that long-term vitamin A (retinol) and beta-carotene supplementation should be avoided in the long term in people at high risk of developing lung cancer, such as smokers and people exposed to asbestos.

Interaction with other drugs

Vitamin A, which has already entered the bloodstream, begins to quickly break down if the body lacks vitamin E. And if there is a lack of vitamin B4 (choline), then vitamin A is not stored for future use. Antibiotics are thought to reduce the effects of vitamin A somewhat. In addition, vitamin A can increase the effects of a substance called isotretinoin and lead to severe side effects.

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