Database of diseases - Practical dermatology

 

The biggest enemy of the skin are oxygen free radicals - also known as oxidants or oxidants. Free radicals disturb skin metabolism, and when they occur in a large amount cause so-called Oxidative stress that damages skin cells and connective tissue. Vitamin A prevents degeneration and, as a consequence, premature aging of the skin. Thanks to its use, the skin regenerates faster.


Vitamin A works outside the cells

Vitamin A as an antioxidant works mainly in tissue spaces, between skin cells, where the fatty environment dominates in which it is soluble. Vitamin E supports it in this environment. Another antioxidant - vitamin C - interacts with the aqueous environment that fills the inside of the cells.

To cover the skin against excess oxygen free radicals and against harmful intrinsic and extrinsic substances, vitamins A, E and C are most commonly used.

Vitamin A withit fights free oxygen radicals

Vitamin A - belongs here to the most important tissue antioxidants. The beneficial effects of using vitamin A, in particular its provitamin beta beta carotene, are known to prevent sun damage and the resulting aging of the skin. Thanks to its oral use, as well as the local effect on the epidermis and dermis - the skin avoids excessive dryness and keratosis, the skin regenerates faster. Experience has shown that its presence protects against nothing but free radicals, but also germs, toxins, as well as strengthens the immune system.


Vitamin A has antioxidant effects throughout the body and skin

The active substance of vitamin A is retinol - a fat-soluble compound, necessary for the growth of the body, differentiation and function of the epithelial tissue of the skin and mucous membranes. Provitamin A - beta-carotene has been shown to prevent tissue damage due to the oxidative action of sunlight. Photoprotective works because it intensifies the production of pigment and prevents the penetration of ultraviolet rays through the skin, the excess of which stimulates the production of free oxygen radicals.


Vitamin A as an antioxidant binds to free radicals and blocks:

- their toxic effects on whole body cells,
- their toxic effects on cell DNA


Strengthens the resistance of the skin and mucous membranes to germs

It has been documented that additional amounts of vitamin A can inhibit age-related shrinkage of the thymus gland, which is one of the most important organs of the immune system. In the thymus, the most advanced immune cells - T lymphocytes mature, track and recognize germs to be able to eliminate them. Vitamin stimulates the activity of immune cells - macrophages and granulocytes that destroy germs, parasites and foreign bodies.


The source of vitamin A - are products of animal as well as vegetable origin

In edible plants, it is in the form of provitamin - carotenoids, which, depending on the region of the world, cover 50 to 80% of the daily requirement for this vitamin. Carotenoids, pigments widely used in plants, and beta-carotene are the most important in human nutrition. It is worth noting that some varieties of carotenoids, compounds from the biochemical family to which carotene belongs - for example, lycopene abundantly found in tomatoes is an even stronger antioxidant. It seems that standardized lycopene concentrates in pharmacies can be expected soon.


Daily requirement for vitamin A:

- in adult males it is approx. 1000μg (5000 IU);
- in women less - about 800 μg (4000 IU);
- in children up to 6 years of age - approx. 400 μg (2500 IU)


The most common causes of vitamin A deficiency are:

- slimming down,

- non-fat, vegetarian diet, vegetarianism,
 
- taking medicines to lower cholesterol,

- impaired absorption of fats.



 

The recommended form of oral vitamin A preparations is beta-carotene

It is provitamin A found in fruits and vegetables. Beta carotene does not show any toxicity even with significant overdose. It is the "initial form" of vitamin A, which means that its properties are activated only after the body transforms into vitamin A (retinol). Because the body processes as much beta-carotene as it needs, there is no harmful to health accumulation of excess vitamin A and is therefore its safe form. The harmless storage of beta-carotene ("peach" color) is evident in the orange-yellow color of the skin and disappears after discontinuation of the vitamin.

Oral preparations of vitamin A and beta-prostene

Vitamin A can be taken either in a natural form - eg in the form of, for example, capsules containing fish liver oil, or in a synthetic form - in the form of capsules or dragees. Beta-carotene is available as a plant extract. It is believed that 2 mg of beta-carotene has equivalent activity to 1 mg of retinol. It is necessary to know that carotenoids are less used from food than pure retinol, eg beta-carotene from food is absorbed only in 1/3, half of which is converted into retinol. The total use of beta-carotene is therefore 1/6 of that of retinol.


What determines the bioavailability of vitamin A in the gastrointestinal tract?

It was also found that the absorption in the human alimentary tract of both carotenoids (eg beta-carotene) and retinol esters is dependent on the presence of fat, which stimulates this process. Consumption of eg 20g fat by adult women or less than 5g fat by children results in a significant decrease in the use of carotenoids and reduction of vitamin A body reserves. The degree of use of vitamin A and carotenoids also depends on the source of food, the presence and quality of protein in diet, natural antioxidants, iron, zinc and dietary fiber, as well as the processing processes used


Contraindications of vitamin A supplementation

Hypervitaminosis A, severe renal and hepatic failure, children up to 7 years of age Do not take preparations containing vitamin A during treatment. To be used with caution during pregnancy and breast-feeding. After high doses - gastrointestinal disorders.

 

ed. Edward Ozga-Michalski, MA

 
Literature
1. Practical dermatology; Małgorzata Opalińska, Katarzyna Prystupa, Wadim Stąpór, Wyd. Lek. PZWL 1997
2. Vitamins, minerals, E numbers, U.Unger-Gobel, ed. MUZA SA, 1997
3. L / Stefan Ball, Antioxidants in human medicine and health, Medyk-2001
4. Tales about vitamins and bioelements; prof. dr hab.Andrzej Danysz, ed. Holbex, 1999
5, Harper Biochemia, Wyd. Bow. PZWL 2000
6. Websites: http: //www.rozanski.henryk.gower.pl/; http://www.sfd.pl/
7. Therapy 2001 - Aging of the skin and its cosmetic therapy -publ. Internet Esculap Dr. med. Maria Noszczyk Institute of Experimental and Clinical Medicine PAS Director: prof. dr hab. med. Mirosław J. Kossakowski
12. PHARMINDEX