GENERICO.ruMedicineDoctors warn of the dangers of vitamin A deficiency

Doctors warn of the dangers of vitamin A deficiency

Important functions of vitamin A.

We grow, we look at the world through the prism of thousands of chemical compounds in our body. They control thinking, behavior and tastes, reports with reference to Sayyes.

Vitamin A is a general term that is usually applied to a group of fat-soluble compounds. It comes in two forms: retinoids and carotenoids. Understanding the difference between the two will help you consume foods more consciously.

Retinoids are a complete vitamin A. That is, our body uses it unchanged. This includes the well-known retinol, which has been buzzing around with advertisements for facial cosmetics. Retinoids are found in animal products such as meat, fish, dairy products.

Carotenoids are the precursors of vitamin A, scientifically – provitamins A, which a person gets from consuming plant foods.

Functions vitamin A

1. The first and very important function is vision

In the body, vitamins of group A are easily oxidized with the participation of enzymes, forming retinals & # 8212; constituent of the rhodopsin protein. Rhodopsin, in turn, is the main light-sensitive compound of the retina (rods). When light hits the retina, the cis-configuration turns into trans-retinal. This process is a trigger that excites an impulse in the optic nerve that is transmitted to the brain. And voila, we see the world even in the dark! & Nbsp; Vitamin A prevents the risks of night blindness.

2. Synthesis of enzymes, which are further involved in a number of formation reactions:

  • mucopolysaccharides: components of connective tissue, cartilage and bones. Low vitamin A levels may not be the only problem when it comes to bone health. Research shows that people with high vitamin A intakes also have a higher risk of fractures.
  • heparin; hyaluronic acid – this is the answer why anti-wrinkle remedies with retinol are so popular (or rub fish oil into the skin);
  • sulfocerebrosides in brain cells;
  • taurine, which stimulates the synthesis of growth hormone, and we grow;
  • liver enzymes;
  • somatomedins A1, A2, B and C, which promote the synthesis of proteins in muscle tissue.

3. Participates in the synthesis of sex hormones

Vitamin A & nbsp; is necessary to maintain a healthy reproductive system in both men and women , ensures normal growth and development of the fetus during pregnancy. In addition, insufficient synthesis of hormones is manifested in rashes on the skin of the face, back and chest. Acne occurs when sebaceous glands become clogged with dead skin and oils. Although physically harmless, they can seriously affect mental health and lead to low self-esteem, anxiety and depression. The exact role of vitamin A in the development and treatment of acne remains unclear. But, isotretinoin & # 8212; one example of an oral retinoid that is effective in treating severe acne. However, this medication can have serious side effects and should only be taken under medical supervision.

4. Supports immunity

Synthesis of interferon, immunoglobulin A, lysozyme. It's all about the barrier function of vitamin A. It is also involved in the production and functioning of white blood cells, which help trap and clear the bloodstream of bacteria and other pathogens. In fact, in countries where infections such as measles and malaria are common, vitamin A supplementation reduces the risk of dying from these diseases.

5. Participates in the synthesis of enzymes of epithelial tissues, preventing their premature keratinization.

6. Activates receptors for calcitriol (vitamin D3)

7. Reduces the risk of certain cancers

In observational studies, consuming more vitamin A in the form of beta-carotene has been associated with a reduced risk of certain cancers, including Hodgkin's lymphoma, and cervical, lung, and bladder cancers. .


Although vitamin A deficiency is rare, many people in developing countries do not get enough vitamin A. Children are at increased risk for hypovitaminosis, affecting about a third of people under five years of age worldwide. It can arise not only due to a meager monotonous diet, early refusal to breastfeeding. Secondary deficiency is a consequence of chronic diseases: disorders of lipid absorption, bile formation, as well as the effects of cigarette smoke and alcoholism. Cystic fibrosis and chronic diarrhea can also increase the risk of a deficiency.

Major signs of vitamin A deficiency. Dry skin and itching

Vitamin A is essential for the regeneration of skin cells. It also helps fight all kinds of inflammation and eczema. Several clinical studies have shown that the drug alitretinoin & # 8212; form of vitamin A, effective in treating eczema.

Dry eyes and blindness

Dry eyes, inability to cry, the so-called night blindness (a sharp decrease in adaptation to darkness) are early signs of vitamin A deficiency. In extreme cases, hypovitaminosis can lead to complete blindness or corneal death (Bitot spots). Research shows that high doses of the vitamin reduced dry eyes by 63% among infants and children taking supplements for 16 months. Patients with night blindness began to see 50% better in the dark after 6 weeks of treatment. Interestingly, they made up for the vitamin deficiency through food.

Problems with conceiving a child

Vitamin deficiency can lead to infertility in both men and women. Studies in rats have shown that females who were deficient in vitamin A had difficulty carrying a fetus and also had an increased risk of miscarriage. Embryos in most cases were born with birth defects. Yes, of course, rats and humans cannot be compared in the degree of organization of the organism itself. But why expose Homo sapiens females to such risks?

Because of the higher levels of oxidative stress in the body of men, they have a greater need for antioxidants. Vitamin A is a natural antioxidant, so sufficient amounts of it will support fertility.

Growth retardation

Children who do not get enough vitamin A may experience developmental delays and stunted growth. In Indonesia, over 1,000 children with vitamin deficiencies have taken high doses of the supplement for four months. Their height increased by 0.39 cm, compared with children taking placebo. At the same time, multivitamin complexes affect growth more than just vitamin A.

Frequent respiratory tract infections

Adults with high levels of vitamin A in their blood may be less at risk of respiratory disease. For infants, especially those born prematurely, taking 10,000 IU of vitamin A per week significantly reduces the risk of getting sick. On the other hand, a controversial study found that vitamin supplements increased the risk of throat and chest infections by 8%. Whom to believe is still unknown. This area of ​​research requires more time and grants for scientists. However, the results are promising.

Acne and breakouts

Low vitamin A levels are often associated with acne. It's all about hormonal imbalance – the synthesis of sex hormones, in which, again, the vitamin is involved. The reason lies within, but, for the most part, depends on factors from outside, namely, proper nutrition. The most famous form of oral vitamin A used to treat acne is & # 8212; it is isotretinoin or accutane. This drug can be very effective, but it also has many side effects.

The danger of hypervitaminosis

Regular consumption of large amounts of fish oil with an approximate retinol dose of 4000 IU/kg causes chronic poisoning, and 25000 IU/kg – acute poisoning. The carotenoid form is not so toxic. & Nbsp; Cases of poisoning with a fatal outcome are possible with the use of shark liver, polar bear, sea animals and cute huskies.

People with certain medical conditions may need more vitamin A. However, healthy adults need 700–900 mcg per day. To eliminate hypervitaminosis, “sweet alcohol” mannitol is prescribed, as well as vitamin E.

Note for pregnant women and expectant mothers

If you decide to take vitamin A, be sure to consult your doctor. Unconscious use of the drug can lead to miscarriages, as well as fetal defects. Even six months before pregnancy, using large doses of the vitamin, a woman is exposed to teratogenic effects in the future!

Vitamin A exists in 2 forms: & nbsp; active, or true vitamin A, retinol, as well as inactive – provitamin A, carotenoids. The first form you consume with animal products, especially fish oil and beef liver. The second is when you eat plant foods, especially if you gnaw on carrots.

When using vitamin A, be it in supplements or with food, you must adhere to the rule of the golden mean. You yourself may not understand when an overdose will occur. Nevertheless, the effect of it will be manifested by severe intoxication, the risks of fetal abnormalities in expectant mothers. But, hypovitaminosis also has a number of unpleasant symptoms: eczema, problems with conception, developmental delays, etc. So, the daily norm for adults ranges from 700 to 900 mcg for women and men, respectively.

Vitamin A performs a number of the most important functions in the human body. It is an immunomodulator, used in the treatment of certain types of cancer and lung infections, participates in the process of vision, and also participates in the synthesis of enzymes, sex hormones and other vital compounds.


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