Vitamin A is added in the AD calcium salt in the form of ethyl ester which is insoluble in water .

AD钙盐中的 维生素 A是以其 乙酸酯的形态加入，而后者不溶于水。

In foods of animal origin the major form of vitamin A is an ester primarily retinyl palmitate which is converted to the retinol ( chemically an alcohol ) in the small intestine .

在动物z来源的食品中， 维生素 A的主要存在形式是 维生素 A 酯，最常见的是维生素A棕榈酸酯，它们在小肠内被转化成维生素A。