Vitamin A is the common name for several organic compounds from the retinoid group. It is also often referred to as retinol, beta-carotene, axerophthol, and provitamin A. It belongs to the group of fat-soluble vitamins. In plants, this compound accumulates and occurs in the form of carotenoids. In the organism, vitamin A is held as retinol in the liver and adipose tissue.
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One of the fundamental roles of vitamin A is to maintain healthy skin. It also plays a vital role in vision, the development of epithelial cells, and supporting the immune system. As an antioxidant, it helps protect cells from the damaging effects of free radicals.
Vitamin A, due to its solubility in fats, is classified as a lipophilic vitamin. It belongs to the vitamins with antioxidant effects, which defend cells from the hurting effects of free oxygen radicals.
The vitamin of youth is the best-known and most frequently used anti-wrinkle ingredient, which allows you to prolong the youthfulness of your skin. Its useful effect on the skin results from the presence of receptors in it, which selectively bind vitamin A molecules.
Retinol is an alcoholic form of vitamin A, which (as the only one) exhibits full biological activity. Retinoids include:
The need for vitamin A varies based on age, gender, and individual health. Pregnant women, people on low-fat diets (such as athletes following a high-carb, low-fat regimen), and patients with liver damage should pay special attention to their vitamin A intake.
Data from 2020 collected and developed by the National Institute of Public Health – National Institute of Hygiene indicate the following recommended daily RDAs (Recommended Dietary Allowances):
It is assumed that the daily intake of vitamin A from retinol (UL, Upper Intake Level) should not exceed 15 thousand micrograms.
It is worth noting that individual forms of vitamin A differ in their chemical structure and their impact strength. Therefore, to determine the content of the compound, the so-called retinol equivalent was used, developed in the 1990s by the SCF (Scientific Committee for Food). It is assumed that 1 mg of retinol corresponds to 6 mg of beta-carotene and 12 mg of other carotenoids. Of course, this does not mean vitamin A should be taken exclusively from animal products. Fruits and vegetables contain much more valuable nutrients than just beta-carotene.
Vitamin A is one of the vitamins that patients often supplement. It is in fact a group of fat-soluble compounds, which includes retinol (vitamin A1), retinal, retinoic acid, and carotenoids. The main carotenoid compounds are: β-carotene, α-carotene, β-cryptoxanthin, lutein, and lycopene.
The most active carotenoid is β-carotene, which is provitamin A. To gain biological activity, it must be transformed, only then does it gain full functionality. α-carotene and β-cryptoxanthin also demonstrate vitamin A activity. Lycopene is a carotenoid that provides vegetables and fruits their red color. It is an antioxidant, which – according to research – prevents DNA damage, thanks to which it can limit the development of prostate cancer, and also plays a role in circulatory system disease prevention. Lutein, on the other hand, prevents macular degeneration.
Vitamin A plays an essential role in the proper vision process, being a component of visual purple or rhodopsin. In addition, it participates in the proper differentiation of epithelial and bone tissue cells and takes part in the production and release of adrenal and thyroid hormones. It is an important factor supporting the maintenance of the accurate shape of mucous membranes and skin and is involved in the sense of taste. In addition, vitamin A has antioxidant potential, thanks to which, together with vitamins C and E, it prevents excessive oxidation of fatty acids, protects against the harmful effects of free radicals, and affects the proper structure of erythrocytes.
Vitamin A takes part in sperm formation, the development of the placenta, and the proper growth of the fetus. Its significant role also involves participation in keeping proper immunity, helping to protect against infections and fight them.
Primary vitamin A deficiency results from an improper diet, and poor in vitamin A and carotenoids. Secondary vitamin A deficiency is caused by diseases that impair the proper absorption, metabolism, and storage of vitamin A. Sick people, despite keeping a healthy and balanced diet, are at risk of hypovitaminosis or total avitaminosis. Conditions that predispose to secondary vitamin A deficiency include:
Vitamin A deficiency is diagnosed when the concentration of retinol in the blood serum drops below 0.7 μmol/L. A drop below 0.35 μmol/L is considered a severe deficiency, which may pose a risk of permanent damage to health.
Symptoms of vitamin A deficiency mainly affect the eyes. One of the earliest symptoms is nyctalopia, or night blindness, in which vision is worsen in low-light conditions. Eye diseases caused by vitamin A deficiency also include:
Vitamin A is involved in keeping the proper functioning of the skin and its products – hair and nails. Characteristic symptoms of vitamin A deficiency include hyperkeratosis or excessive keratinization of the epidermis. The skin all over the body becomes rough and unpleasantly dry, and this is accompanied by excessive hair loss and brittle nails.
The immune system's functioning also depends on the correct level of vitamin A in the body. Multiple scientific studies have shown that vitamin deficiency increases the risk of contracting numerous infectious diseases. Additionally, in children, lack of vitamin A can cause growth and development disorders, especially when it is accompanied by lacks of other vitamins and minerals.
Along with supplementation, a properly balanced diet rich in products with vitamin A should be introduced. The best sources are animal products, in which it occurs in the form of retinol.
Beta-carotene is in vegetables and fruits with vibrant yellow, orange, or red. Carrots, pumpkins, sweet potatoes, red peppers, and apricots are particularly high in beta-carotene. Additionally, dark green leafy vegetables like spinach, kale, and broccoli are excellent sources. The body converts this element into the active form of vitamin A.
The functions of vitamin A in the body are very important, so it is important to take care of its proper level in the blood. Vitamin A supplementation may be advised in various situations, especially when there is a risk of lack or there are specific medical indications.
When laboratory test results confirm a vitamin A deficiency, supplementation may be necessary to increase the levels of this vitamin in the blood and improve health.
Women during pregnancy and breastfeeding have an increased need for vitamin A because it is important for the proper development of the fetus and the production of breast milk. In the case of a lack or low intake of vitamin A in the diet, supplementation may be advised. However, it is important not to overdo it, which can be toxic to the fetus.
Some chronic diseases, such as digestive diseases of the digestive system, can lead to impaired absorption of vitamin A. In such cases, supplementation may be necessary to compensate for the lack of it.
In some cases, especially when you have trouble seeing in low-light conditions, your doctor may recommend a vitamin A supplement to improve your vision.
As you age, your body may become less able to absorb and utilize vitamin A. Older adults may have increased vitamin A requirements and supplements may be advised.
Vitamin A plays an essential role in maintaining the health of your skin, mucous membranes, and immune system. Therefore, supplementation may be advised to prevent certain conditions, such as acne.
It is important to remember that you should always consult your doctor before starting a vitamin A supplement, who can perform an appropriate assessment and recommend the appropriate dosage to avoid the risk of toxicity and adverse effects.
Excess vitamin A in the body is called hypervitaminosis. It occurs when the amount of the compound provided to the body exceeds its capacity to use it and this condition persists for a long time. As a rule, exceeding the advised standards by supplying vitamin A only from food is impossible, although it can happen in the case of unjustified use of vitamin supplementation. Scientific studies confirm the toxic effects of excess vitamin A, including teratogenic effects (harmful to the fetus and may result in the development of congenital defects), which is why pregnant women should pay special attention to their diet.
Typical symptoms of hypervitaminosis include:
Hypervitaminosis can even lead to spontaneous bone fractures as a result of a decrease in their thickness.
Retinol is a fat-soluble vitamin with hydrophobic properties. It is a lipophilic liquid that is highly sensitive to oxidation. Due to its action, it is one of the active substances often used in cosmetics. Natural retinoids can be found in the cosmetics composition, which include the weakest retinyl esters and substances with similar biological activity: retinol and retinaldehyde.
When the first wrinkles appear on the skin, it is a sign that it is worth asking a cosmetologist for advice and reaching for the first cosmetic with retinol, preferably for use at night.
To obtain optimal, side-effect-free action, it is worth checking whether the cosmetic contains, in addition to retinol, the following ingredients:
The concentration of retinol in cosmetics is also crucial. Retinol creams usually contain 0.05-1% retinol. Cosmetics with a low concentration of retinol are advised for people starting the treatment until the skin tolerance to retinol is built up. It is also worth using them in more delicate areas, i.e., around the eyes and on the contours of the lips. Cosmetics containing higher retinol concentrations should be used for facial and décolleté skin care.
Retinol is a substance with a strong effect on numerous processes in the skin. For this reason, the use of retinol preparations must be well thought out. They should not be combined with substances such as:
During retinol treatment, you should not use a solarium. You should also avoid sunlight and use creams with high SPF 50+ protection. You should also not perform mechanical peeling, microdermabrasion, or laser therapy.
In recent years, a natural plant substance called bakuchiol, which is called vegan retinol, has become increasingly popular. In reality, it is a completely different chemical substance. However, it has similar desirable properties to retinol without the undesirable irritating effects.
Bakuchiol is a phenol that is a derivative of terpenes. It occurs, among others, in the Psoralea corylifolia plant, growing in China and India, where it has long been used in Ayurvedic medicine. Bakuchiol can also be safely used in the summer. It has, among others, the following effects:
