ABSTRACT
As noted before, many food chemicals are nutrients. Nutrients, as defined, are necessary for growth, maintenance, and reproduction of living organisms. In the overall scheme of nutrition, nutrients can be divided into macronutrients and micronutrients. Macronutrients include fats, carbohydrates, and proteins. Micronutrients can be divided into vitamins and minerals, the latter including trace elements. Several decades of nutritional research have been devoted to defining the intake levels of macro-and micronutrients necessary to meet the needs of people and levels safe for healthy individuals. Such information has been summarized in several publications emphasizing recommended dietary allowances (RDAs) and, recently, the dietary reference intake (DRI).
