What is vitamin A?

Vitamin A, a heat-resistant fat-soluble vitamin but sensitive to oxidation by air and light, plays a crucial role in maintaining skin health and preparing it for sunlight exposure. It exists in the human body in two main forms: retinol, which is the active form of the vitamin, and beta-carotene, a precursor converted by the body into vitamin A as needed.

Role and benefits of vitamin A

• Vision and night vision: Vitamin A is essential for the proper functioning of the retina, contributing to the perception of shapes and colors, and plays a vital role in the eye's adaptation to darkness.
• Cellular regeneration and skin protection : It promotes cellular regeneration and is involved in the formation and protection of skin and mucous tissues, playing a vital role in the healing process.
• Hormonal and immune function: Vitamin A regulates the function of various glands, including endocrine and sebaceous glands, and enhances immune response.
• Growth and antioxidants: It is also necessary for normal bone and teeth growth. Beta-carotene, a powerful antioxidant, helps neutralize free radicals, thereby slowing cellular aging.

Food sources of vitamin A

• Animal sources: Retinol is mainly found in butter, dairy products, egg yolks, organ meats, and fish liver oil.
• Plant sources: Beta-carotene is abundant in colorful fruits and vegetables such as carrots, apricots, sweet potatoes, and cruciferous vegetables like cauliflower and broccoli. Assimilation of beta-carotene is enhanced by the presence of fats during meals.

What are the differences between vitamin A and beta-carotene?

Vitamin A and beta-carotene are closely related but have distinct characteristics and functions in the body:

Vitamin A

Vitamin A is a fat-soluble vitamin that plays a crucial role in many bodily functions, including vision, immune system, reproduction, and maintaining the health of skin and mucous membranes. It exists in two main forms:

• Retinol: This is the active form of vitamin A found in animal-derived foods such as liver, butter, dairy products, and fish liver oils.
• Retinyl esters: These are stored forms of vitamin A also found in animal-derived foods.

Beta-carotene

Beta-carotene is a type of carotenoid, a natural pigment found in plants. It serves as a precursor to vitamin A, meaning the body converts it into retinol. Beta-carotene is an important source of vitamin A for individuals following a vegetarian or vegan diet. It is particularly abundant in colorful fruits and vegetables such as carrots, sweet potatoes, spinach, and apricots.

Key differences

• Source: Retinol comes from animal-derived foods, while beta-carotene is mainly obtained from plant sources.
• Function: Retinol is directly usable by the body, whereas beta-carotene must first be converted into retinol before it can be used.
• Biological activity: Retinol has higher biological activity compared to beta-carotene. This means the body more efficiently utilizes retinol than beta-carotene.
• Safety: Beta-carotene is generally considered safer in terms of supplementation as it poses a lower risk of toxicity. The body converts only the required amount of beta-carotene into vitamin A, thus reducing the risk of overdose, unlike retinol which can accumulate to toxic levels if consumed in excess.

Specific cautions regarding vitamin A consumption

Taking retinol-based dietary supplements is not recommended for pregnant women or those planning to conceive, due to the risk of congenital malformations associated with excess vitamin A. Smokers should also avoid high doses of vitamin A.

Vitamin A in history

In 1913, vitamin A was discovered by the English researcher Hopkins, marking the first discovery of a vitamin and justifying the choice of the letter "A" to denote it.