Useful, but insidious vitamin A: how its deficiency and excess are dangerous for humans

Vitamin A is a fat-soluble biologically active substance necessary for the normal functioning of the body. It is also called retinol or beta-carotene; it requires bile for better absorption. As a reserve, it accumulates in the liver and fat cells. With a decrease in the vitamin, hypovitaminosis develops, and with a complete deficiency of the substance, vitamin deficiency develops.

Vitamin A hypovitaminosis and what it can lead to

The following conditions can lead to a lack of retinol:

1. ​Adherence to a diet that involves limited consumption or complete exclusion of foods with vitamin A and healthy fats necessary for its absorption.
2. ​Chronic infectious diseases.
3. ​Various liver pathologies - cirrhosis, hepatitis, fibrosis.
4. ​Irritable bowel syndrome.
5. ​Oncological pathologies.
6. The body's high need for retinol. It occurs during pregnancy and breastfeeding, as well as during stressful situations, physical and intellectual work.
7. ​Diathesis in childhood.

The initial prerequisites for a decrease in vitamin levels are indicated by dryness and flaking of the dermis, and impaired visual acuity. Vaginosis may develop.

Due to retinol deficiency, the immune system suffers significantly. Therefore, a person becomes more susceptible to various infections.

Hair loss

It is normal to lose about 100 hairs per day. But if you notice large strands or clumps of hair on your pillow or in the shower, you may be low on iron. You are not alone. This is one of the most common nutritional deficiencies in the world. To check iron, the doctor may prescribe LVSS, Transferrin saturation with iron, Complete blood count (CBC/Diff) with leukocyte count without ESR, Reticulocyte count, Ferritin.

If you're a new mom and your hair is falling out like a waterfall, don't panic right away. During pregnancy, hair usually grows faster and thicker. After childbirth, estrogen and hair fall along with it. In a year everything should be back to normal. Iron deficiency after childbirth is quite common.

Signs of retinol deficiency

Vitamin A is simply indispensable for the normal functioning of the body. It is a participant in many physiological processes and is responsible for the strength of the immune system.

The main symptoms of retinol deficiency are:

1. Frequent inflammatory diseases of the gastrointestinal tract.
2. ​Poor condition of nails and hair. They become weak, brittle and lifeless. Hair falls out a lot and becomes dull.
3. ​Vision deterioration, especially at night.
4. ​Burning, itching, dryness and other discomfort in the eyes. Over time, clouding of the cornea appears, even leading to blindness.
5. ​Dryness and flaking of the skin, especially noticeable in the area of ​​the knees and elbows.
6. ​Decreased secretion of sweat glands.
7. Frequent development of bacterial and infectious pathologies of the bronchopulmonary system. This is due to the drying out of the epithelium, so the body becomes less susceptible to pathogens.
8. ​Deterioration of the reproductive system. Sexual dysfunction and lack of libido in men are observed. Among women, there are problems with menstruation, conception, breast tumors, miscarriages and gynecological diseases.
9. ​Improper growth and development of children. The musculoskeletal system, brain and spinal cord are affected.

Symptoms of vitamin deficiencies

Manifestations of vitamin deficiency (hypovitaminosis) depend on which particular vitamin is missing.

A
deficiency manifests itself primarily in the form of ophthalmological and dermatological pathologies. “Twilight vision” – the ability to confidently navigate in the absence of insufficient lighting – is impaired. Bright daylight is poorly perceived. The conjunctiva is affected (conjunctivitis develops) and the cornea (it softens, perforation becomes possible). The skin becomes dry and vulnerable to infection (typical manifestations are pyoderma and furunculosis). A lack of vitamin A also increases the likelihood of developing respiratory diseases (rhinitis, bronchitis).

Vitamin B1 (thiamine) deficiency
manifests itself in the form of a complex of symptoms called
beriberi disease
. The most typical neurological disorders are: headache, fatigue, intolerance to mental stress, general weakness, uncertainty when walking, sensations of numbness and tingling. Pain in the heart area, tachycardia, nausea, constipation and some other manifestations are also possible.

B2
deficiency is manifested by damage to the lips (lips crack, pockets appear in the corners of the mouth), and the oral mucosa (stomatitis develops). Dry skin is also observed; Possible weight loss and anemia.

Vitamin
B6
has skin and neurological manifestations. The most typical symptoms are dry skin, seborrheic dermatosis (scalp, face, neck), redness of the tongue, cracks in the corners of the mouth, numbness and tingling sensations (hands and feet), anemia, and seizures are possible in young children.

Vitamin
B12
is one of the common causes of anemia, which most often results in symptoms such as general weakness, pale skin, shortness of breath, tachycardia, tinnitus, and dizziness.

Vitamin
C
(ascorbic acid) deficiency is historically known as
scurvy
. Characteristic symptoms: redness, swelling and bleeding of the gums (in severe cases, teeth may fall out), muscle weakness, painful legs when walking, bruising may appear on the skin.

D
deficiency can cause rickets and osteoporosis, as it leads to changes in bone tissue. Children may experience bone deformation; adults (especially older people) often suffer from fractures. Other manifestations: weakness, increased fatigue, muscle cramps in the arms and legs, insomnia, weight loss and loss of appetite.

Vitamin E deficiency

causes hemolysis (decomposition of red blood cells), leading to reproductive dysfunction. Main manifestations: muscular dystrophy, impaired coordination of movements, blurred vision. The skin loses elasticity, hair becomes dull and begins to break.

K
deficiency leads to impaired blood clotting and increased bleeding (nasal, subcutaneous and gastrointestinal hemorrhages are possible).

Consequences of vitamin A deficiency

A lack of vitamin A negatively affects overall well-being, affecting all systems and organs.

If a deficiency of the substance develops and there is no proper treatment, this can lead to serious complications:

1. ​Diseases of the gastrointestinal tract.
2. Pathologies of the bronchopulmonary system of infectious origin.
3. ​Death of eye structures, up to complete blindness.
4. Irreversible, serious processes in the bone system in children.
5. Frequent gynecological diseases of an inflammatory and infectious nature.

Hypovitaminosis is a group of diseases caused by a lack of one or more vitamins in the body. The extreme degree of hypovitaminosis is vitamin deficiency.

The following types of hypovitaminosis are distinguished: beriberi (lack of thiamine), pellagra (lack of nicotinic acid), “night blindness” (lack of vitamin A), scurvy (lack of vitamin C), rickets (lack of vitamin D), as well as other pathological conditions, associated with a deficiency of folic acid, biotin, vitamins K, B2, B6 and B12.

Currently, severe hypovitaminosis is rare in developed countries. However, the results of laboratory studies indicate that mild forms of hypovitaminosis, occurring without pronounced symptoms, are very widespread even in countries with a high standard of living. The main reasons for the lack of vitamins in Europe and the USA are chronic diseases or operations on the gastrointestinal tract, diets, alcoholism, taking a number of medications, and inadequate parenteral nutrition (administration of nutrients through injections). In Russia, hypovitaminosis is quite common, especially among the elderly and children. The severity and prevalence of various types of hypovitaminosis may vary depending on the region and time of year.

Treatment of hypovitaminosis consists, accordingly, in replenishing the lack of vitamins. The prognosis for timely treatment is favorable. However, some changes that occur with prolonged, severe deficiency of certain vitamins may be irreversible.

Synonyms Russian

Lack of vitamins, vitamin deficiency diseases, vitamin deficiency.

English synonyms

Hypovitaminosis, vitamin deficiency, vitamin deficiency diseases, vitamin deficiency disorders, lack of vitamins.

Symptoms

The manifestations of hypovitaminosis are very diverse; they can impair the functioning of almost all organs and systems of the body. The severity of symptoms depends on the degree of vitamin deficiency. The most common signs of hypovitaminosis are:

• weakness, fatigue,
• anemia,
• bleeding,
• dermatitis,
• nervous system dysfunction,
• disruption of the gastrointestinal tract,
• osteogenesis disorder,
• visual impairment,
• violation of the physical and mental development of the child.

General information about the disease

Vitamins are low-molecular compounds of various structures necessary for the proper functioning of the body. A person needs vitamins A, C, D, E, K and B vitamins (thiamine, riboflavin, niacin, folic acid, pantothenic acid, biotin, vitamins B12, B6). With the exception of D and K, which are synthesized in the body, most vitamins are found in food. Despite very small quantities, they are vital for the full growth and development of the body. Vitamins are involved in most metabolic reactions.

The cause of hypovitaminosis can be a lack of vitamins in food (with an unbalanced diet, fasting), impaired absorption of vitamins in the intestines (with diseases of the gastrointestinal tract, after surgery) or an increase in the need for vitamins (with pregnancy, lactation, taking anticonvulsants and other medications ). As a result of vitamin deficiency, biochemical processes in the body are disrupted, which can manifest itself as a number of general symptoms (decreased appetite, weakness, fatigue) and specific signs characteristic of each type of hypovitaminosis.

Vitamins are most often divided into fat-soluble and water-soluble.

1. Fat soluble

• Vitamin A (retinol). Participates in the synthesis of rhodopsin, the retinal pigment, and maintaining the integrity of the epithelium. Contained in liver, fish, eggs and as a provitamin (carotenoids) in vegetables and some fruits. Its deficiency is manifested by dry eyes, skin rashes and a weakened immune system.
• Vitamin D. Converted in the body into active metabolites that perform specific functions in individual organs. Stimulates the development of bone tissue, the functioning of the immune system, including antitumor immunity, increases the absorption of calcium in the intestine. The bulk of vitamin D is synthesized in the skin under the influence of ultraviolet radiation; some comes from food (cod liver, egg yolk, butter). In developed countries, dairy products are additionally fortified with vitamin D. Its deficiency causes rickets in children and osteomalacia in adults.
• Vitamins of group E have antioxidant properties, that is, they slow down the aging process. They are found in vegetable oil and nuts. When they are deficient, red blood cells and neurons are destroyed, which leads to anemia and nonspecific neurological symptoms.
• Vitamin K. It is partially synthesized by bacteria found in the human intestine, but this amount is not enough for the normal functioning of the body. Contained in green vegetables. Vitamin K deficiency causes bleeding. Newborns are especially susceptible to its deficiency, in whom it can cause hemorrhagic disease.

2. Water soluble

• Vitamin C, or ascorbic acid. Participates in the synthesis of collagen, a number of amino acids and hormones, is responsible for the strength of the vascular wall and bone tissue, improves the functioning of the immune system and wound healing. Contained in broccoli, strawberries, citrus fruits, tomatoes, sweet peppers, rose hips, cabbage. With a deficiency of vitamin C, scurvy develops, which is characterized by bleeding, tooth loss, brittle bones, gingivitis, and poor wound healing.
• Biotin. Participates as a coenzyme in the metabolism of carbohydrates and fats. Contained in egg yolks, liver, legumes, yeast, nuts, cauliflower. Biotin deficiency leads to disruption of the physical and mental development of children, impairs the functioning of the immune system, and can cause rashes and paralysis.
• Folic acid (folate). Necessary for the maturation of red blood cells and the development of the fetal nervous system. Its deficiency occurs when folate is not absorbed in the intestine or when taking medications, although this vitamin is found in sufficient quantities in many foods of both plant and animal origin. Hypovitaminosis causes megaloblastic anemia and congenital neural tube defects.

• Nicotinic acid (niacin, nicotinamide). Participates in redox reactions. Contained in meat, fish, legumes, cereals. The lack of niacin in the diet can be compensated by the use of tryptophan, since the latter can be converted into nicotinic acid in the body. Niacin deficiency causes dermatitis, diarrhea or constipation, and neurological disorders, but is very rare in developed countries.
• Thiamine (vitamin B1). Participates in the metabolism of proteins, fats, carbohydrates, amino acids, in the work of the central and peripheral nervous system, myocardium. Contained in many products, especially cereals, meat, potatoes. With a lack of thiamine, beriberi disease occurs - a disruption of the nervous system and myopathy.
• Riboflavin (vitamin B2). Provides many reactions of carbohydrate metabolism and maintains the integrity of the mucous membranes. With riboflavin deficiency, signs of damage to the mucous membranes appear: dermatitis, anemia.
• B6 vitamins (pyridoxine, pyridoxal, pyridoxamine). They participate in the metabolism of lipids, amino acids, and in reactions that ensure the functioning of the central nervous system, blood cells, and skin. Contained in cereals, legumes, liver, fish. Their deficiency can cause dermatitis, lymphopenia, depression, and seizures.
• Vitamin B12 (cobalamin). Participates in the synthesis of DNA, methionine, maturation of red blood cells, and the functioning of the central nervous system. Contained mainly in products of animal origin: meat, fish, eggs, milk. Cobalamin deficiency leads to anemia and various neurological disorders: paresthesia, ataxia, impaired consciousness.

Who is at risk?

• Pregnant and lactating women.
• Those who are malnourished and do not consume specific foods – only a varied diet can provide the required amount of vitamins from different groups.
• People on diets.
• Taking anticonvulsants.
• Suffering from chronic diseases of the gastrointestinal tract or having undergone surgery on the stomach or intestines.
• Alcoholics.

Diagnostics

Symptoms of severe forms of hypovitaminosis are, as a rule, quite specific, which allows the doctor to easily assume a deficiency of a particular vitamin. However, in cases of slight hypovitaminosis and the presence of concomitant diseases with similar symptoms, a number of laboratory or instrumental studies may be required.

Laboratory diagnostics

• Determination of vitamin levels in blood serum
• Vitamin B12 (cyanocobalamin)
• Vitamin B9 (folic acid)
• Vitamin A (retinol)
• Vitamin B1 (thiamine)
• Vitamin B5 (pantothenic acid)
• Vitamin B6 (pyridoxal 5-phosphate)
• Vitamin C (ascorbic acid)
• Vitamin D, 25-hydroxy (calciferol)
• Vitamin E (tocopherol)
• Vitamin K (phylloquinone)
• General blood analysis. With a deficiency of folic acid or vitamin B12, megaloblastic anemia can be observed, with a deficiency of vitamin B6 - lymphopenia.
• Total alkaline phosphatase. May be increased with rickets.
• Prothrombin index (PI), INR (international normalized ratio). With vitamin K deficiency, the prothrombin index can be increased with normal levels of other coagulation parameters: fibrinogen, thrombin time, activated partial thromboplastin time, platelet count. In case of vitamin C deficiency, the coagulogram is normal.
• Calcium in daily urine. With rickets, calcium levels are reduced. To monitor the treatment of rickets with vitamin D, the Sulkovich test can also be used to determine the amount of calcium in a single portion of urine. The result is indicated in crosses from 0 to 4.
• Ionized calcium. With rickets it can also be reduced.
• Serum calcium. Calcium levels in rickets may be reduced or within normal limits due to increased concentrations of parathyroid hormone.
• Phosphorus in serum. This indicator is sometimes reduced with rickets.
• Homocysteine. Homocysteine ​​levels increase with vitamin B12 deficiency.
• Parathyroid hormone. Parathyroid hormone levels may be elevated due to rickets.

Other studies

• X-ray of bones. With rickets, changes in bone tissue resemble atrophy, flattening of the epiphyses of the bones is observed, the periosteum is raised and calcified.
• Fibrogastroduodenoscopy (FGDS) is an examination of the digestive system using an endoscope. Allows you to identify diseases that result in impaired absorption of vitamins.
• MRI (magnetic resonance imaging) and CT (computed tomography). Imaging methods that can be used to differentiate hypovitaminosis from other diseases accompanied by damage to the nervous system, such as tumors.

In some cases, consultation with specialists such as a neurologist, ophthalmologist, or gastroenterologist is required.

Treatment

Treatment consists of oral, intramuscular and intravenous administration of appropriate doses of vitamins, as well as treatment of diseases leading to disturbances in the absorption and metabolism of vitamins in the body.

Prevention

Prevention of hypovitaminosis consists of a balanced diet, as well as taking additional doses of vitamins if necessary (for example, during pregnancy or during recovery from serious illnesses).

Recommended tests

• General blood analysis
• Total alkaline phosphatase
• Vitamin B12 (cyanocobalamin)
• Vitamin B9 (folic acid)
• Vitamin A (retinol)
• Vitamin B1 (thiamine)
• Vitamin B5 (pantothenic acid)
• Vitamin B6 (pyridoxal 5-phosphate)
• Vitamin C (ascorbic acid)
• Vitamin D, 25-hydroxy (calciferol)
• Vitamin E (tocopherol)
• Vitamin K (phylloquinone)
• Activated partial thromboplastin time (aPTT)
• Coagulogram No. 1 (prothrombin (according to Quick), INR)
• Fibrinogen
• Thrombin time
• Calcium in daily urine
• Serum calcium
• Ionized calcium
• Serum phosphorus
• Homocysteine
• Parathyroid hormone, intact
• Laboratory diagnosis of rickets
• Monitoring the prevention of rickets
• Fat-soluble vitamins (A, D, E, K)
• Water-soluble vitamins (B1, B5, B6, B9, B12, C)
• Complex blood test for vitamins (A, D, E, K, C, B1, B5, B6, B9, B12)

Literature

• MarkH. Beers (chief ed.) – The Merck Manual. Guide to Medicine. Diagnostics and treatment – ​​2011
• Harrison S. Principles of Internal Medicine. 18Ed.

How to compensate for the lack of retinol

A subtle deficiency of vitamin A in the body can be compensated for by a special diet. To do this, the patient’s diet is enriched with foods high in this substance: butter, cheese, liver, eggs, in particular yolks, fish oil, many seafood, cottage cheese, sour cream.

You can also include plant-based foods that contain a lot of beta-carotene in your menu. This is all kinds of leafy greens, vegetables and fruits (carrots, oranges, tangerines, pumpkin, sea buckthorn).

By consuming these foods, you can ensure good prevention of vitamin A deficiency.

Types of vitamins

All vitamins are divided into two large groups:

Water-soluble vitamins:

• B1 (thiamine);
• B2 (riboflavin);
• B3 or PP (neacin);
• B5 (pantothenic acid);
• B6 (pyridoxine);
• B12 (cyanocobalamin);
• Sun (folic acid);
• C (ascorbic acid);
• N (biotin).

Fat-soluble vitamins:

• A (retinol);
• D (calciferol);
• E (tocopherol);
• K (menadione).

Fat-soluble vitamins are stored in adipose tissue or in the liver. Water-soluble vitamins do not have the ability to accumulate in the body and quickly leave it along with urine. Therefore, hypovitaminosis of water-soluble vitamins is most common.

Treatment of vitamin A deficiency

Therapeutic measures to restore retinol levels are carried out only after consultation with a specialist. The patient should undergo a series of tests. If a severe vitamin deficiency is confirmed, then you cannot do without taking medications.

As a rule, retinol is sold in the form of capsules with liquid contents. They are taken orally during meals. Vitamin A oil solution is used externally. Depending on the purpose, the required therapeutic dose should be measured. For example, for hair, nails or skin care.

Retinol is often included in various vitamin complexes. The substance is much better absorbed in the body if used together with vitamin E. Therefore, it is recommended to purchase medications that contain both products: tocopherol and retinol.

Beta-carotene, like retinol, is available from pharmacies in the form of capsules for oral administration. The course of therapy and duration are determined by the doctor, taking into account the clinical features of the deficiency of the biologically active substance.

Taking medications on your own is contraindicated, since excess retinol is just as dangerous to health as its deficiency. Uncontrolled use of the vitamin negatively affects the functioning of the liver, endocrine system and intestines. It also provokes irritability, nervousness, and intolerance to light in the eyes. During pregnancy, vitamin A in large quantities can contribute to disruption of intrauterine development.

Diagnosis of vitamin deficiency

The diagnosis is based on medical history, clinical picture, and examination results. The doctor determines what tests the patient needs to undergo, but there is a list of laboratory tests that are prescribed primarily if hypovitaminosis is suspected.

• Determination of the level of vitamins and minerals (calcium, phosphorus) in blood serum in urine.
• Spectral analysis of hair and nails for microelements.
• General and biochemical blood test.
• Coagulogram.
• Urine and stool analysis.

If hypovitaminosis is caused by a disease, then additional studies are prescribed to establish the nature of the pathology: X-rays, ultrasound, FGDS, magnetic resonance and computed tomography.

At the modern level of development of medicine, how to find out which vitamins are missing in the body does not present any particular difficulties. In addition to laboratory tests, functional tests are used, the purpose of which is to establish the level of saturation of the body with vitamins.

The saturation of the body with vitamin A is examined using the twilight vision adaptation test, and the level of vitamin C is determined by a vacuum capillary stability test.

3. Symptoms and diagnosis

Almost always, the first symptom that seriously worries the patient and alarms the doctor about hypovitaminosis A is “unreasonable” visual impairment. This trend is far from the only one, but it is so typical, universal and well-known that the special term xerophthalmia, or “dry eye syndrome” is often used to designate the clinical picture of hypovitaminosis A (strictly speaking, the cause of xerophthalmia is not necessarily a deficiency of retinol, but this is true the most common etiological factor).

Since vitamin A is necessary to maintain sufficiently sensitive color and twilight vision, the so-called hypovitaminosis develops. night blindness (nyctalopia, hemeralopia) – the inability to clearly distinguish objects in low light conditions, a kind of “darkening” of the visual field. This symptom is quickly accompanied by a “sandy” pain in the eyes due to insufficient secretion of tear fluid, inflammation of the eyelids and conjunctiva, mucus and crusts in the corners of the palpebral fissure. In other systems of the body, increasing dyspeptic symptoms are observed (nausea, lack of appetite, stool disorders), increased sensitivity to pain and temperature influences, dry and brittle hair, deterioration of the nail plates and cuticles, dandruff, peeling of the skin. Due to the weakening of the protective functions of the immune system, respiratory infections often develop during this period.

The diagnosis is established clinically, based on the presence of a characteristic symptom complex; as a rule, a consultation with an ophthalmologist is necessary (and in some cases it is the ophthalmologist who conducts the initial appointment with a patient with hypovitaminosis A).

Due to the sufficient specificity of the symptoms, diagnostic difficulties usually do not arise, but if necessary, a clarifying laboratory test can be carried out (determining the serum concentration of retinol and carotene).

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