The lipid-soluble (Fat-soluble) vitamins are Vitamin A, D, E and K. They are non-polar hydrophobic molecules and are all isoprene derivatives. They are not synthesized by the body in adequate amounts and must, therefore, be supplied by the diet. They are absorbed efficiently when normal fat absorption is taking place. Once absorbed, they are transported in the blood, in lipoproteins or attached to specific binding proteins. The lipid-soluble vitamins have diverse functions.