Retinol, the dietary form of vitamin A, is a
fat-soluble, antioxidant
vitamin important in vision and bone growth. It belongs to the family of chemical compounds known as
retinoids. Retinol is ingested in a precursor form; animal sources (milk and eggs) contain retinyl
esters, whereas plants (carrots, spinach) contain carotenoids. Tissue cells convert these precursors to
retinol, and then to either retinal or retinoic acid.
Many of the non-vision functions of vitamin A are mediated by retinoic acid, which acts at intracellular
retinoic acid receptors. Retinoic acid is used medicinally as a topical treatment for acne. The other main metabolite,
retinal, is used in vision.
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