In the absence of vitamin a, it develops. Eyes and vision
- This condition is caused by prolonged insufficient intake of vitamin A from food, especially if rice is a staple food (does not contain carotene).
- Vitamin A deficiency occurs when there is a lack of protein in the diet (marasmus or kwashiorkor), mainly due to food deficiencies (but storage and transport of vitamin A is also impaired).
Secondary vitamin A deficiency
- This condition occurs when there is a problem converting carotene to vitamin A, or when absorption, storage, or transport of vitamin A is reduced.
- Occurs in celiac disease, tropical sprue, giardiasis, cystic fibrosis, other pancreatic diseases, cirrhosis, shunting duodenum and obstruction of the bile ducts.
Epidemiology
The following segments of the population are most susceptible to the occurrence of vitamin A deficiency:
- Vitamin A deficiency is rare in developed countries, but extremely common in developing countries especially in sub-Saharan Africa and South Asia.
- Globally, vitamin A deficiency affects 100-140 million children, of which 4.4 million have xerophthalmia.
- Recent immigrants or refugees from developing countries.
- Toddlers and children preschool age living below the poverty line.
- In pregnant women, vitamin A deficiency occurs especially in the last trimester (the need for the fetus and mother in vitamin A is highest during this period). Read more - Vitamin A during pregnancy: dosage, effect on the fetus, norm.
Other risk factors for vitamin A deficiency include:
- Fat malabsorption, cholestasis, inflammatory disease bowel disease (IBD), cystic fibrosis (cystic fibrosis), pancreatic insufficiency, or after small bowel transplant surgery.
- Vegan diet.
- Alcoholism.
Vitamin A deficiency symptoms
Mild forms of vitamin A deficiency may not cause any symptoms. However, there may still be an increased risk of developing respiratory infections and gastroenteritis, as well as growth retardation and bone development. There is also a risk of infertility secondary to impaired spermatogenesis and an increased risk of miscarriage.
Eyes and vision
Pathognomonic changes occur in the eye (usually bilateral, although they can be of varying degrees):
- Poor adaptation to the dark - night blindness.
- Keratomalacia (thinning and, ultimately, ulceration of the cornea - colliquative necrosis).
- Dryness of the conjunctiva, dryness of the cornea, xerophthalmia.
- Bitot's spots (areas of abnormal squamous cell proliferation and keratinization of the conjunctiva, causing oval and triangular foamy patches on the periphery of the albuginea).
- Corneal perforation.
- Blindness due to structural damage to the retina.
- Decreased levels of vitamin A increase the risk of blindness in children, virus-infected measles.
Changes in the eye
Early symptoms begin with itching, burning, and inflammation of the eyelids, followed by various diseases eye.
Prolonged vitamin A deficiency leads to a condition known as nyctalopia, or blindness, in which a person is unable to see well in dim light, especially after exposure to bright light. The "blindness" is due to the fact that vitamin A combines with a protein in the retina of the eye to form a pigment called rhodopsin (visual purple). Rhodopsin is formed by a combination of vitamin A-aldehyde (retinone) and a protein (opsin). It bleaches in strong light. During the photochemical reaction, some vitamin A is lost. If there is enough vitamin A, the eyes quickly adjust to the low light, and you can see almost immediately.
Night blindness is more common in poor people. Men suffer more than women. A pregnant woman often suffers from night blindness, partly due to underlying medical conditions and partly due to increased need in vitamin A during this period. Night blindness sometimes occurs due to a physical defect in the eyes or in other cases. This condition associated with vitamin A deficiency is called Functional Night Blindness.
Xerophthalmia
This condition occurs when vitamin A deficiency is severe and prolonged. Xerophthalmia occurs due to changes in epithelial tissues eyes. The cornea becomes dry, wrinkled, dull, cloudy and pigmented. The tear glands stop producing tears that normally keep the eye moist by flushing away bacteria and other foreign matter, leading to dryness and inflammation. eyelids and loss of eye luster. Inflammation leads to ulceration. The final stage is keratomalacia - softening and destruction eyeball leading to blindness.
Xerophthalmia is sometimes associated with Bitot's spots, which are well-demarcated foamy white or grayish irregular areas present in the periphery of the cornea of the eye. These spots do not interfere with vision. Keratomalacia usually affects children between the ages of 1 and 5 due to a lack of vitamin A in their diet.
Epithelial changes
Vitamin A deficiency leads to atrophy (degeneration) and keratinization (hardening) of the epithelium. Epithelial cells flatten and accumulate on top of each other. This increases the susceptibility to serious infection not only of the eyes, but also of the nasal passages, sinuses, middle ear, pharynx, mouth, respiratory tract, lungs and genitourinary tract. The epithelium of the eye is so severely damaged that the condition is incurable.
Skin and hair
A person experiencing a lack of vitamin A in the body may also experience the following symptoms concerning the skin and hair:
- Dry skin, dry hair, itching.
- Follicular hyperkeratosis secondary to occlusion hair follicles, with keratin plugs.
Vitamin A deficiency can lead to xeroderma (dry and scaly skin with itching) and follicular hyperkeratosis (dry, rough, scaly skin). There is a thickening of the keratin layers of the skin on the palms and soles. follicles like goose pimples, appear first on upper parts arms and thighs, then on the shoulders, back and buttocks. This condition is called frinoderma or "toad skin". sweat glands the skin is blocked by horny plugs of keratin, in connection with which their secretion decreases.
Respiratory system
The mucous membranes of the respiratory organs, such as the nose, throat, trachea, and bronchi, become dry and rough. Thus, Airways exposed increased risk development of a bacterial infection.
Digestive system
Due to vitamin A deficiency digestive tract dries up, resulting in decreased secretion of digestive juices, lack of absorption and increased susceptibility to intestinal infection and diarrhea.
reproductive system
Keratinizing metaplasia occurs in renal pelvis, bladder, uterus, oviduct and accessory sex glands. In women, vaginitis can be observed.
Urolithiasis disease
This is a disease in which there are urinary calculi (stones) consisting of calcium phosphate. Due to the lack of vitamin A, keratinization of the epithelium of the urogenital tract occurs, which is later accompanied by bacterial invasion.
Changes in the skeletal system
Lack of vitamin A leads to uneven development of the skeleton, including the skull and spinal column. This leads to distortion and damage to the head and spinal cord. The growth of bone and teeth is noticeably weakened.
Reduced resistance to infection
Vitamin A is essential for the maintenance and functioning of the body's mucous membranes. When there is a deficiency, the shells become thin, dry, porous and scaly. They cannot fulfill their protective functions, and bacteria have free access. Thus, a lack of vitamin A reduces the barrier function against certain infections.
Treatment of vitamin A deficiency
Treatment for subclinical vitamin A deficiency includes consuming vitamin A-rich foods such as liver, beef, chicken, eggs, fortified milk, carrots, mangoes, sweet potatoes (yam), and leafy green vegetables.
Good animal sources of vitamin A include:
- liver
- egg yolks
- whole milk
- butter
- whole small fish (liver intact)
Animal sources of vitamin A, including milk, are more bioavailable than plant sources such as carrots and other orange-yellow fruits and vegetables, and dark green leafy vegetables.
You can see a list of foods rich in vitamin A on this page - 20 foods rich in vitamin A: a list of foods with vitamin A.
Medicines
For clinically apparent vitamin A deficiency, treatment is reduced to daily oral intake vitamin A supplements.
An overdose of vitamin A can cause symptoms and signs such as:
- skin roughness
- dry hair
- liver enlargement
- increased erythrocyte sedimentation rate, increased calcium concentration and alkaline phosphatase in serum
Taking into account the data showing that high levels vitamin A can cause birth defects, pregnant women, and women who may become pregnant, are not recommended to take vitamin A supplements (including fish oil supplements). They are also advised not to consume liver or foods such as liver paste or liverwurst, unless directed by a physician.
Forecast
If the patient applies for medical care when the deficiency is subclinical, the prognosis is good. As blindness progresses, the prognosis worsens. Irreversible conditions include punctate keratopathy, keratomalacia, and corneal perforation.
- For patients with early moderate eye problems fast treatment can lead to complete preservation of vision without residual deterioration (fully restored within a few weeks).
- In developing countries, a severe degree of vitamin A deficiency, often triggered by significant malnutrition, leads to death in most cases. Mortality in children with severe vitamin A deficiency is up to 50%.
- Only about 40% of patients with corneal xerophthalmia continue to see a year later (25% are completely blind and the rest are partially blind).
Prevention
Liver, beef, chicken, eggs, whole milk, fortified milk, carrots, mangoes, orange fruits, sweet potatoes, spinach, kale, and other green vegetables are among the foods rich in vitamin A.
It is recommended to eat at least five servings of fruits and vegetables a day to ensure the normal intake of carotenoids in the body. A variety of foods such as breakfast cereals, pastries, breads, crackers, and cereal bars are often fortified with vitamin A.
People at increased risk of vitamin A deficiency should take vitamin A supplements to reduce morbidity, mortality and the risk of blindness in children early age aged 6 months to 5 years.
Due to a lack of vitamin A in the body, negative changes can occur - visual impairment, conjunctivitis, xerophthalmia, skin hyperkeratosis. In addition, people suffering from a deficiency of this vitamin are prone to diseases of the intestines and respiratory tract. Let's find out together why this is happening.
Importance of Vitamin A
Vitamin A plays important role in the human body:
- takes part in cell growth processes;
- supports color vision;
- participates in the exchange of organic compounds;
- participates in the synthesis of sex hormones;
- supports defensive forces organism;
- protects from impact free radicals.
Vitamin A is a fat-soluble substance that consists of a number of structurally similar compounds: retinol, dehydroretinol, retinal, retinoic acid, esters and their spatial isomers.
Retinol helps maintain a stable blood sugar level. Therefore, vitamin A is considered to be particularly important in the treatment of hypertension, diabetes and obesity.
Causes of hypovitaminosis A
Vitamin A deficiency can be caused by a violation of its absorption in the intestine. This usually occurs in chronic diseases of the intestines, liver, pancreas, celiac disease, iron deficiency anemia. Eating even a small amount of dietary fat can reduce the absorption of vitamin A. In addition, low protein intake also contributes to a decrease in vitamin A levels.
The cause of hypovitaminosis can be a significant loss of it by the body in cancer, diseases urinary tract and chronic infectious diseases.
At birth, the level of vitamin A in a child is reduced. But it quickly rises, since the main food of the newborn (breast milk) is rich in this vitamin. Therefore, with a healthy appetite, the baby is protected from hypovitaminosis. However, if after switching to adult nutrition the child's diet will contain a small amount of foods rich in vitamin A, this will affect his health. Age from 2 to 3 years is especially dangerous. To prevent this from happening, the baby needs to eat more vegetables, fruits, dairy products, liver, and take fortified supplements.
Signs of deficiency
Hypovitaminosis manifests itself in different ways. Its main symptom is the loss twilight vision. Other symptoms may soon appear. Processes of keratinization skin and mucous membranes (mainly in the oral cavity) are disturbed.
Dry skin in teenagers before puberty can be a sign of a retinol deficiency. In this case, its keratinization and peeling occurs.
In adults, hypovitaminosis can cause:
- hair loss, dandruff;
- brittle nails;
- increased keratinization of the skin;
- premature aging of the skin, the formation of wrinkles;
- lacrimation in the cold;
- redness of the eyelids, the formation of mucus in the corners of the eyes;
- erectile dysfunction.
Retinol deficiency contributes to the development of dermatological diseases, hypersensitivity tooth enamel, diseases digestive systems s ( atrophic gastritis), liver cysts, pancreatic cancer, gynecological pathologies(mastopathy, tumors of the mammary glands). In addition, a deficiency of this substance can cause frequent colds and chronic diseases upper respiratory tract, growth and development retardation (in children).
The main problem associated with vitamin A deficiency is that it impairs performance. immune system and the body becomes vulnerable to various infections.
Lack of carnitine causes the development of muscle necrosis. Characteristic features this disease: muscle pain, weakness, general malaise. Vitamin A deficiency is very dangerous and requires treatment.
Treatment
Retinol deficiency in the human body is corrected with medical preparations. To do this, the doctor prescribes an appointment synthetic means containing large amounts of vitamin A.
Retinol
An effective remedy for hypovitaminosis A. It comes in capsules or liquid form (for external use). It is necessary to take the drug in accordance with the doctor's instructions. You need to follow this rule, even if your goal is prevention. Required dose determined by age, and individual characteristics organism. At lung disorders or medium degree daily dosage Retinol for an adult is 33,000 IU, for a child - 5,000 IU. For prevention, they usually use 3300 IU per day (for an adult).
During pregnancy, the use of Retinol should be treated with extreme caution. Excessive amounts of this drug can lead to irreparable disorders in the development of the baby. You should also remember the dangers of Retinol when planning to conceive a child. Active ingredient this drug accumulates in the body.
Tocopherol
It is used in cases where there is a simultaneous deficiency of vitamins A and E. K popular means, containing both of these vitamins, is Aevit.
The course of treatment usually takes several weeks. But in severe cases, one course of therapy may not be enough, additional or repeated treatment will be required.
Vitamin A (retinol) plays a primary role in maintaining general health a person, in particular - in maintaining the work of the immune, reproductive systems, the organ of vision and the integrity of epithelial tissues. Lack of it organic compound can negatively affect primarily visual acuity and skin condition. If the doctor suspects a lack of retinol in the body, he prescribes a determination of its concentration in venous blood. The analysis can be taken in the direction or independently (for preventive purposes). It is also important to examine the organs of the gastrointestinal tract: hypovitaminosis can develop due to a decrease in the quality of absorption of vitamin A in the small intestine.
How to suspect a lack of retinol?
Vitamin A deficiency causes the following symptoms:
- visual disturbances, especially at dusk;
- dry skin;
- mucosal damage;
- increased fragility of nails and hair;
- physical weakness, decreased performance;
- peeling of the skin;
- increased sensitivity of the cornea, the formation of ulcerative defects on the mucous membrane of the eyes;
- dizziness;
- tendency to develop urolithiasis;
- decreased activity of the immune system, a tendency to develop infectious and inflammatory diseases.
In children, hypovitaminosis A can even lead to a delay in physical and mental development, great weakness, reduced twilight vision. If you notice at least a few symptoms of a lack of retinol, you should consult a doctor. The specialist will conduct an examination and put accurate diagnosis, and if necessary - will prescribe the treatment of the disease and the observance of a certain diet.
Experience world scientists showed that when retinol reserves are depleted, people have serious problems with immunity, skin, and the reproductive system. Even banal SARS can lead to severe bronchopulmonary complications and death from infections.
If hypovitaminosis A develops, the epithelium suffers internal organs. This causes keratinization of the respiratory mucosa, urinary organs, intestines, organ of vision. Secretion epithelial cells bronchi, lungs slows down, which increases the risk of developing respiratory diseases With bacterial complications and others adverse effects. There is keratinization of the skin, and first of all, the limbs are damaged.
Epithelium urinary tract is damaged, calculi begin to form around fragments of torn tissues. Prolonged vitamin A deficiency can result in urolithiasis disease and its associated complications. Against the background of a lack of retinol, spermatogenesis in men is disrupted, testicular tissue atrophy may occur. But vitamin A deficiency is especially dangerous for children and pregnant women.
Risks of Retinol Deficiency During Pregnancy
Pregnant women are at risk. During the period of bearing a child, retinol takes part in the development of many organs and tissues of the fetus. British scientists conducted studies on mice, the results of which found that even a moderate deficiency of retinol increases the synthesis of a protein that destroys brain neurons. These consequences are irreversible.
A lack of retinol during fetal life can lead to a decrease in the ability and early development Alzheimer's disease in adulthood. Hypovitaminosis A leads to pregnancy fading, severe weakness in women, manifested by the threat of miscarriage and high risk development of malformations in the unborn child.
Be sure to pay attention to your diet even in preparation for pregnancy. A large number of vitamin A is found in fish oil, liver, butter, milk, green and yellow vegetables, and legumes. Additionally, take multivitamin complexes.
The role of vitamin A
True vitamin A is retinol (found in food of animal nature), and its predecessor is carotene "provitamin A" (part of vegetables, fruits, greens). In the liver, carotene is converted to vitamin A, and its reserve is stored in adipose tissue. Thus, even if a person eats poorly for a limited period of time, but has fat all over the body, there will be no hypovitaminosis. Vitamin A accumulated in adipose tissue will be gradually released, depending on the condition of the body.
Here are the main functions of retinol:
- participation in the production of protein structures, enzymes and hormonal substances;
- maintenance of twilight vision;
- participation in the growth of the skeleton;
- keeping active reproductive system person;
- preservation of the basic functions of epithelial and bone cells;
- protection against free radicals and premature aging;
- prevention of the development of malignant tumors;
- maintaining full-fledged work urinary organs and gastrointestinal tract.
Not so long ago, experts discovered the antitumor effect of retinoids. It has been experimentally proven that vitamin A minimizes the effects of carcinogens, maintains the normal functionality of epithelial cells and prevents their growth.
Modern research has shown that a lack of vitamin A dramatically increases the body's susceptibility to viruses and bacteria. The reason for the development of infections lies in the lack of intake of retinol with food. Additional Introduction vitamin A helps reduce the risk of measles among children, promotes easy flow illness.
The amount of vitamin A
In adults, the need for vitamin A is 700-900 mcg per day. It is enough for a woman to consume 600-700 mcg per day, for a man a little more - about 900 mcg. The norm of vitamin A for a child under 6 months is 400 mcg, from 6 to 12 months - 500 mcg per day. Children older than a year and adolescents should receive up to 500-900 micrograms of vitamin A per day. The need for retinol during pregnancy increases - up to 800-900 micrograms per day.
It is important to remember that bile is necessary for the absorption of vitamin A. It is synthesized in the presence of fat in the diet. Low-calorie diets are dangerous for the development of beriberi, especially for women, who can bring down hormonal background and lose their former reproductive functions.
High doses of retinol are toxic! Do not exceed the recommended dosage! But the toxic properties of retinol appear when daily intake exceeds 3000 mcg.
Foods High in Retinol
A decrease in the amount of vitamin A in the blood is observed with an unbalanced diet, when there are no animal products, vegetables and fruits.
It takes several weeks for retinol levels to normalize. Treatment necessarily includes changing the diet and taking vitamin preparations.
A large amount of retinol is found in the following products:
- beef liver;
- butter;
- egg yolks;
- fish fat;
- sour cream;
- caviar;
- cottage cheese;
Foods high in carotene:
- carrot;
- bell pepper;
- broccoli;
- pumpkin;
- spinach;
- soy and peas;
- apricots and peaches;
- sea buckthorn;
- melon;
- rose hip.
How to increase the absorption of vitamin A?
Vitamin A deficiency can be primary or secondary. Primary occurs in children and adults who eat poorly, refuse fruits and vegetables, milk, cheese, cottage cheese and butter, replace healthy meals semi-finished products, canned food, sweets. Abrupt termination breastfeeding also increases the risk of beriberi in a child.
Secondary retinol deficiency is associated mainly with impaired absorption of fats, with problems in the functioning of organs that are involved in bile formation. Vitamin A is fat soluble - it is necessary to maintain sufficient levels of fat for its absorption. Deteriorates the absorption of retinol lack of zinc, which is involved in the metabolism and transport of vitamin A.
Vitamin E, which is considered a powerful antioxidant, is also used to increase absorption. It contributes to the absorption of retinol from the intestines and the maintenance of basic useful properties vitamin A. It is not recommended to use at the same time as retinol Activated carbon which may impair absorption useful substances in the intestine.
Vitamin A deficiency pathological condition associated with a deficiency of a substance in the body. It is manifested by visual impairment, xerophthalmia, conjunctivitis, dry skin and other symptoms. A lack of vitamin A leads to diseases of the intestines and respiratory tract.
The role and norms of vitamin A in the body
Vitamin A is a fat soluble substance. It has two forms: carotene (provitamin A, vitamin A2, found in vegetable food) and retinol ( original vitamin, A1, comes from animal food). Conversion of carotene to retinol, reserve accumulation occurs in the liver. Additional depot - adipose tissue. The body always has a supply of retinol, which is released when needed.
Retinol performs important functions:
- accelerates oxidative processes;
- slows down aging;
- participates in growth, cell regeneration, formation of dental and bone tissue;
- responsible for maintaining the integrity of the epithelium;
- stimulates the immune system, gonads;
- is an antioxidant: protects cells from damage and malignant degeneration;
- takes a direct part in the work of the organs of vision. Vitamin A is a participant in the resynthesis of rhodopsin, a pigment found in rods retina. With a lack of vitamin A, the synthesis is disturbed, hemeralopia develops - a decrease in twilight vision;
- responsible for normal development embryo.
It is very important for children - it ensures growth and development in accordance with age.
The norms of its daily intake (80% of the norm in the form of retinol, the remaining 20% - in the form of carotenoids):
- 0-12 months: 0.4 mg;
- 1-3 years: 0.45 mg;
- 4-6 years: 0.5 mg;
- 7-10 years: 0.7 mg;
- 11-50 years old: 0.8 mg;
- pregnant women: 0.8 + 0.2 mg;
- lactating mothers: 0.8 + 0.4 mg.
Persons involved in heavy physical labor, need 1 mg of the vitamin daily. This category is at risk for hypovitaminosis A.
Causes of vitamin A deficiency
The level of vitamin A in newborns is low, but in the first days of life it rises rapidly due to intake with colostrum, breast milk, adapted mixtures. In healthy children and adults on balanced diet, the risk of developing hypo- and beriberi A is small. What leads to a pathological condition?
- A diet deficient in foods rich in vitamin A. Minimization in the diet of milk, vegetables, fruits, oils, eggs, liver, fats can lead to insufficiency;
- Being on parenteral nutrition;
- Low intake of protein foods. Leads to a lack of protein - a carrier of the vitamin;
- Violation of the absorption of retinol in the intestine with: celiac disease, celiac disease, cholecystitis, spastic colitis, Crohn's disease, diseases of the liver, pancreas, intestines, anemia, alcoholism, cholestasis, disseminated tuberculosis, long-term use mineral oil;
- Loss of vitamin by the body with: oncological diseases, chronic infections, diseases of the urinary tract;
- Conditions in which there is an intensive consumption of vitamin A: rapid growth and development, pregnancy, lactation, increased physical, mental stress, stress.
Pathogenesis of A-vitamin deficiency
The exogenous form of hypovitaminosis A is rare, the condition is mostly secondary - i.e. mediated by some pathology.
Vitamin A deficiency causes pathological change skin, its derivatives and mucous membranes: atrophy of sweat excretory, salivary glands, dry skin and membranes lining the respiratory tract (nostrils, paranasal sinuses, trachea, bronchi). According to some vitaminologists, psoriasis is also associated with hypovitaminosis A.
Signs of Vitamin A Deficiency
They do not develop immediately, they indicate a pronounced hypovitaminosis.
- Dryness of the mucous membranes of the mouth, nose;
- Single white spots on the oral mucosa;
- Dryness, peeling of the skin;
- (late symptom);
- Deep cracks in the skin in the area of the knee and elbow joints;
- The appearance of wrinkles, early aging;
- "Goosebumps" on the hips;
- Acne;
- Severe hair loss;
- Dandruff;
- Fragility of the nail plates;
- Deterioration of twilight vision;
- Soreness in the eyes in bright light;
- Dryness, dullness of the conjunctiva;
- keratinization of the cornea;
- Decreased secretion of the lacrimal glands;
- Plaques of Iskersky - Bito on the sclera of the eyes;
- In severe cases, necrotic softening of the cornea (keratomalacia), ending in blindness.
The combination of reduced twilight vision, dryness, clouding of the conjunctiva - sure sign deficiency of vitamin A in the body.
Vitamin A deficiency in children is manifested by growth retardation, constant fatigue, decreased immunity, dryness, pallor of the skin, color blindness, a drop in twilight vision.
Nonspecific symptoms of vitamin A deficiency:
- decrease in performance
- insomnia,
- reproductive dysfunction,
- decreased immunity,
- frequent, long-term infections.
Symptoms of long-term A-vitamin deficiency
Prolonged hypovitaminosis A leads to beriberi and serious problems with health:
- dermatitis;
- intestinal infections;
- anemia;
- bronchitis, sinusitis, pneumonia;
- purulent encephalitis;
- cysts in the liver;
- urinary incontinence;
- mastopathy, cervical erosion, thrush in women;
- decreased libido and erection in men;
- chronic infections.
The role of vitamin A deficiency in the development of pancreatic and lung cancer is not excluded.
Diagnosis of its deficiency
The approach to diagnosis is complex.
- Biomicroscopy of the eye (yellowish and white small plaques);
- Determination of the content of vitamin A in blood serum (norm: 0.3 to 0.8 μg / ml);
- Study dark adaptation vision (leading symptom).
Treatment of vitamin A deficiency
A diet rich in provitamin and vitamin A is prescribed. If hypovitaminosis is associated with a violation of the diet, this measure is sufficient. It is important to remember that A is a fat-soluble substance: fats are necessary for its absorption and must be present in food. Smoking and alcohol cessation is required. 
- Retinol preparations are administered orally or intramuscularly. Daily therapeutic dose 25,000-50,000 IU of retinol (rarely at maximum daily dose 100,000 IU). At internal reception the dose is divided into 2-3 doses, with injection- injected with one infection. The course of treatment is 2-4 weeks, in prophylactic doses - 2-3 months.
- The dose of retinol for children is calculated individually by age, the upper allowable level- no more than 1000 mcg (20,000 IU). Average doses:
- children up to a year 1650 ME;
- children 1-6 years old 3300 ME;
- children from 7 years old 5000 ME.
Vitamin A preparations for children and adults
- Retinol acetate oil solution, 100,000 IU in 1 ml;
- Retinol acetate (vitamin A capsules) for children over 18 years old and adults, 33,000 IU in 1 capsule.
- How to give children vitamin A? oil solution- on a piece of black bread. Capsules - whole, washed down with water.
- Vitamin A and E are often prescribed together. A popular drug for children from 14 years old and adults: Aevit.
Deficiency and excess of vitamin A are equally dangerous for the body. Long term treatment retinol in doses of 100,000 IU per day is fraught with the development of hypervitaminosis, which is characterized by: subcutaneous hemorrhages, vomiting, nausea, headache, skin redness. Self-treatment and changing the dose without a doctor's prescription is unacceptable.
Sources of vitamin A and carotene / per 100 gr. product:
| Products | Retinol (IU) - animal food | Carotene (ME) - plant food |
| Beef liver | 15000 | — |
| pork liver | 5000 | — |
| Butter | 2000 | — |
| Calf's liver | 4000 | — |
| Sour cream | 700 | — |
| Curd 0% fat | 130 | — |
| Fat cottage cheese | 800 | — |
| Herring | 110 | — |
| Milk | 90 | — |
| Carrot | — | 15000 |
| Parsley | — | 13000 |
| Rowan red | — | 10000 |
| Sorrel | 10000 | |
| Spinach | — | 10000 |
| lettuce green | — | 3200 |
| Prunes | — | 2000 |
| Pumpkin | — | 1600 |
| tomatoes | — | 850 |
| Peas | — | 800 |
| Chanterelles | — | 800 |
| Peaches | — | 750 |
| apricots | — | 700 |
| White cabbage | — | 630 |
| Green beans | — | 450 |
| Plum | — | 370 |
| Blackberry | — | 300 |
| Green peas | — | 200 |
Prevention
Rational nutrition is an easy way to prevent vitamin deficiency for healthy person. For people suffering from diseases that disrupt the absorption of the vitamin in the intestines, periodic intake of retinol preparations in prophylactic doses (5000-10,000 IU) is relevant for 2-3 weeks better than multivitamins Vitrum, Duovit, Complivit and etc.).
Consequences
A running process is dangerous with a significant deterioration in vision, a malfunction of the immune, digestive systems, premature aging. A lack of vitamin A causes disease and is fraught with a high risk of cancer. To prevent this, at the first sign of a lack of vitamin A, you should consult a doctor.
