Vitamin A, Effects On The Body And Content In Foods

Vitamin A (retinol) is the first vitamin to be studied, which was first discovered in 1913, and thus got its name “vitamin A”.

It is a fat-soluble vitamin, in nature, there are two main forms of it – ready-made vitamin A (retinol) and vitamin A provitamin (carotene), which is broken down to vitamin A in the human body, namely in the liver.

Properties of Vitamin A:

1. Transformation of light in the retina into nerve impulses that our brain perceives as visual images. Vitamin A is very important for photoreception, it is necessary for the synthesis of visual pigment in the retina, which is responsible for twilight vision.
2. Proper growth and development of skin and mucous membranes. Indeed, vitamin A is used in the treatment of almost all skin diseases (acne, acne, psoriasis, etc.). In case of skin damage (wounds, sunburn), vitamin A accelerates healing processes, stimulates collagen synthesis, improves the quality of newly formed tissue, and reduces the risk of infections.
3. It affects the formation of antibodies by leukocytes, which ensures the maintenance of immunity and protection of the body against various infections.
4. Steroid hormones synthesis, stimulation of corticosteroids, androgens, and estrogen production.
5. It affects the number and motility of spermatozoa in men, i.e. affects male reproductive function.
6. Growth and development in childhood and adolescence. Retinol is necessary for normal embryonic development, embryo nutrition, and reduction of the risk of pregnancy complications such as underweight newborns.
7. Iron transport and production of red blood cells, i.e. maintain the proper number of red blood cells in the body, which provide oxygen transport to the cells of the whole body.
8. Bone growth and regeneration.

Vitamin A (retinol) has the ability to accumulate in the liver. If retinol is consumed for a very long time in increased doses, it begins to become toxic to the body.

The daily dose of vitamin A is different for absolutely all age and gender groups. Men need 650-950 mcg of vitamin A per day, and women need 600-800 mcg, but for pregnant women, the daily requirement for vitamin A increases by 100 mcg, and for nursing mothers – by 410 mcg of this vitamin.

Clinically significant diagnostic symptoms of vitamin A deficiency in the body:

1. Early skin aging with the formation of wrinkles.
2. Dandruff.
3. Increased pain and temperature sensitivity.
4. Hypersensitivity of tooth enamel.
5. Accumulation of crusts and mucus in the corners of the eyes, a feeling of ‘sand’ in the eyes, and redness of the eyelids.
6. Weakened erection, rapid ejaculation, weakness of the bladder sphincter, etc.
7. The most well-known symptom of hypovitaminosis A is the so-called “chicken blindness” (night blindness or hemeralopia) – a sharp deterioration in vision in low light.

Signs of hypervitaminosis:

An overdose of vitamin A can cause abdominal pain, menstrual delays, enlarged liver and spleen, gastrointestinal disorders, hair loss, itching, joint pain, nausea, vomiting, and small cracks in the lips and corners of the mouth.

It is observed in chronic hypervitaminosis A:

Dryness and pigmentation of the skin, hair loss, brittle nails, pain in the joints and bones, diffuse bone thickening, enlargement of the liver and spleen, and dyspeptic phenomena.

Vitamin A content in 100 g of food:

• Carrots – 9000 mcg.
• Parsley – 7800 mcg.
• Dates – 1200 mcg.
• Pumpkin – 960 mcg.
• Tomatoes – 510 mcg.
• Green peas – 480 mcg.
• Liver – 4500 mcg.
• Butter – 600 mcg.