Absorption: Well absorbed from the GI tract after oral administration; some processes are active, some are passive. Absorption of water-soluble vitamins generally increases in deficiency states. Absorption of some lipid-soluble vitamins may require bile acids.
Distribution: Widely distributed; cross the placenta and enter breast milk. Fat-soluble vitamins (A, D, E, and K) are stored in fatty tissues and the liver.
Metabolism and Excretion: Utilized in various biologic processes. Excess amounts of water-soluble vitamins (B vitamins, vitamin C, and folic acid) are excreted unchanged by the kidneys.