Vitamin A

What is vitamin A?

Vitamin A, or retinol, is one of the fat-soluble vitamins essential to the body.

Vitamin A was the first vitamin to be discovered, which explains the letter it bears. It was first isolated from the retina, giving it the name "retinol".

It is a fat-soluble vitamin (i.e. soluble in fats), stored in large quantities by the body, and found in its natural state either in its "free" form (retinol) or in the form of provitamin A (i.e. precursor of vitamin A), which the body then transforms into vitamin A according to its needs. The best known form of provitamin A is beta-carotene. These intakes are most often expressed in micrograms of retinol activity equivalent (RAE).

What is its function?

Vitamin A plays an important role in the quality of vision, which is its best known action.

It also contributes to a healthy immune system and plays an important role in the development and growth of bones and skin. This is the reason why, in the last century, children were regularly given cod liver oil, which is very rich in vitamin A.

Beta-carotene, a precursor of vitamin A, has important antioxidant properties that vitamin A does not have. Moreover, it could be toxic only at very high doses and after a prolonged use, at higher doses than the vitamin A itself, which can become toxic during overdoses, in particular during pregnancy.

Where to find it and what are its benefits?

Vitamin A is found in foods of animal origin: butter, eggs, milk, cheese, offal, liver, etc.

Provitamin A, and in particular beta-carotene, is found in fruits and vegetables: carrots, apricots, mangoes, red peppers, lettuce, parsley, spinach, leeks, lamb's lettuce, dark green leafy vegetables, crucifers, sweet potatoes, etc. Generally, the more pronounced their coloring, the more they contain. Finally, the assimilation of beta-carotene is greatly increased by the presence of fat: for example, a salad of grated carrots alone will provide beta-carotene which will be poorly assimilated compared to the same preparation including a little olive or rapeseed oil.

Deficiency and excess

Vitamin A deficiency is practically non-existent in developed countries. On the other hand, pregnant women or women wishing to become pregnant must be particularly attentive to their vitamin A intake, because an excess during these periods can be associated with congenital malformations.

At high doses, beta-carotene intake can cause orange skin discoloration, called carotenoderma, but provitamin A intake is almost always safe.