Vitamin A (or retinol) is a powerful antioxidant that plays a vital role in many biological processes: vision, epidermal keratinization, and cell differentiation.
As an essential micronutrient, our bodies cannot produce it, so it must be included in our diet. It is stored in large quantities in the body, either as retinol (its free and active form) or as provitamin A (a precursor to vitamin A), such as beta-carotene, which the body then converts according to its needs.
Vitamin A from food is stored in the liver until the body needs it. It then binds to proteins before being transported wherever it is needed. It is involved in many metabolic pathways. Vitamin A plays an essential role in vision, cell differentiation, and cell growth. Consequently, it helps keep the skin in good condition. In addition to contributing to iron metabolism, vitamin A plays a role in immunity.
Its main benefits
- It improves vision: it helps maintain a healthy cornea and helps the eyes adapt to changes in brightness and see in the dark by acting on retinal cells.
- It promotes tissue growth and repair: in the event of an injury, it promotes skin healing and, in the event of a fracture, bone regrowth. It is obviously essential for growing children. It also helps prevent infections and stimulates the immune system. In fact, the skin and mucosal cells lining the respiratory, digestive, and urinary tracts act as a barrier and form the body's first line of defense against infections. Vitamin A maintains their functions.
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It contributes to skin health: it stimulates the renewal of skin cells:
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It has antioxidant properties: beta-carotene, the best-known precursor of vitamin A, belongs to the carotenoid family, which consists of powerful antioxidants that help prevent a number of degenerative diseases.
It protects the body against damage caused by free radicals and against the irritating effects of tobacco and pollution. It has also demonstrated a protective effect against ulcers and high blood pressure.
The best sources
The two main forms of vitamin A come from different sources:
- Preformed vitamin A (or retinol): it is found mainly in foods of animal origin, such as cod liver oil, high-quality animal liver, egg yolks, and non-industrial dairy products.
- Provitamin A: it is found mainly in the form of beta-carotene in all orange or yellow fruits and vegetables (carrots, apricots, sweet potatoes) and in green leafy vegetables.
Excess and deficiency of vitamin A
- Excess can cause nausea, fatigue, sleep disturbances, dry skin, itching, hair loss, muscle pain, headaches, or even liver problems in cases of chronic poisoning. For these reasons, all supplements, such as dietary supplements, should be limited to 1,000 micrograms (µg). During pregnancy, excess vitamin A can cause complications for the fetus.
- Vitamin A deficiencies are common in undernourished countries. They can cause significant symptoms, including eye problems.
Daily vitamin A requirements:
The recommended intake is approximately 1 mg, depending on age, sex, and physiological conditions.
