The Vitamin A is a nutrient that the most visible benefit was concentrated in the skin. We know by many names such as retinoic acid, retinol, vitamin antirexeoltálmica, biosterol or betacarotene. However Vitamin A is a poly alcohol.
Here are the most important: The retinol is the main form of vitamin A in the diet and is found only in animal products . Carotenes and derivatives, provitamins or act as precursors of vitamin A, which exist in many plant substances. And then … what is so named retinoic acid? It is the active form of retinol skin and regulates queratogénesis is the generation process of the stratum corneum of the skin.
The Vitamin A is a nutrient animal . It is in its complete form in oils of animal origin, butter, egg yolk, milk and meat (especially liver) and some fish.
However carotenes (and beta-carotene) found in dark green leafy vegetables such as spinach, lettuce and cabbage and some vegetables such as pumpkin, carrots and yellow corn. Bearing in mind that a considerable amount of carotene is lost when these foods are dried in the sun, so it is recommended to consume fresh form. Anyway, we can not assert that the WHO recommended amount of vitamin A (retinol 750 mg per day for adults) can be achieved “only” consuming vegetables (carotenes) because conversion to retinol is not effective.
One more thing of beta-carotene (precursor of vitamin A), must take into account that does not accumulate, ie, the body absorbs only the amount needed and the rest discarded. It is therefore important to know when we plan our diet. Only vitamin A in its final structure can accumulate in the liver.