ABSTRACT
The fat-soluble vitamins comprise vitamins A, D, E, and K, whose biological activities are attributed to a number of structurally related compounds known as vitamers. Also included are those carotenoids that are precursors of vitamin A. Recommended dietary allowances (RDAs) based on human epidemiological and experimental animal studies have been published in the United States for vitamins A, D, E, and K (National Research Council, 1989). Other countries and international bodies have compiled similar recommendations. In the United States and Canada, uid milk is supplemented by law with vitamin D to a level of 400 international units per quart (10 μg/0.95 L) to meet the RDA of 10 μg. Other commodities, such as margarine, milk products, ready-to-eat breakfast cereals, and dietetic foods, are commonly supplemented with vitamins A, D, and E. Except for infant formulas, vitamin K is not added to foods. The addition of vitamins to a particular processed food is intended to provide a specic proportion of the RDA.
