Fat soluble vitamins are not readily excreted and stored in fat cells.
Retinol is one of the animal forms of vitamin A.
When converted to the retinal (retinaldehyde) form, vitamin A is essential for vision, and when converted to retinoic acid is essential for skin health, teeth remineralization and bone growth. Lack of vitamin A causes xerophthalmia.
Xerophthalmia is a medical condition in which the eye fails to produce tears. It may be caused by a deficiency in vitamin A and is sometimes used to describe that lack, although there may be other causes.