Three different forms of vitamin A ,are active in the body: retinol, retinal, and retinoic acid

Retinol

supports reproduction and is the major transport form of the vitamin.

Retinal

is active in vision and is also an intermediate in the conversion of retinol to retinoic acid

Retinoic acid

acts like a hormone, regulating cell differentiation, growth, and embryonic development

facts

The cells of the body can convert retinol and retinal to the other active forms of vitamin A as needed

Foods derived from animals provide retinol in a form that is easily digested and absorbed.

Foods derived from plants provide carotenoids, some of which have vitamin A activity.

The body can convert carotenoids like β-carotene, α-carotene and β-cryptoxanthin into vitamin A.

The primary sources of vitamin A

Retinol is found in liver, egg yolk, butter, whole milk, and cheese.
Carotenoids are found in orange-flesh sweet potatoes, orange-flesh fruits (i.e., melon, mangoes, and persimmons), green leafy vegetables (i.e., spinach, broccoli), carrots, pumpkins, and red palm oil Vitamin A benefit

beta-caroteneis the most powerful when it comes to turning into vitamin A; twice as muchbeta-carotene becomes vitamin A than does alpha-caroten

Lutein is a type of vitamin called a carotenoid. It is related to beta carotene and vitamin A

Isotretinoin naturally derivative of vitamin A and is detectable in the bloodstream of all people.

Vitamin A in large doses has the same effects as Isotretinoin, both good and bad, but quickly becomes harmful since it builds up in the tissue. (Important: Don't take any vitamin A while on Isotretinoin).