chapter  11
8 Pages

Vitamin A

WithJames L. Schardein, Orest T. Macina

Vitamin A is a fat-soluble essential vitamin available from natural as well as synthetic sources. The vitamin promotes bone growth, tooth development, and reproduction; helps form and maintain healthy skin, hair, and mucous membranes; and builds the body’s resistance to respiratory infections. The studies described are those related to excess vitamin A, as deficiency states of the vitamin also have developmental toxicity properties. The pattern of malformations is said by several investigators to be a phenocopy of those defects induced by the vitamin A congener, isotretinoin, a recognized potent human teratogen and developmental toxicant. A number of pertinent reviews addressing the toxicity of vitamin A excess in animals as well as humans were published. Vitamin A, structurally similar to tretinoin, is a highly hydrophobic compound that is larger in size in comparison to the other toxicants within the compilation.