intake level is dependent on the specific indicator of adequacy identified in the DRI report for that nutrient. Depending on the nutrient, the indicator of adequacy may incorporate not only research on deficiency diseases, but also evidence for risk reduction for chronic diseases and amounts to maintain health. Scientific data have not identified an optimum level for any nutrient for any life stage or gender group, and the DRIs are not presented as such. Therefore for this study, key elements that the committee considered were the various criteria for adequacy and how these were related to developing a reference value for nutrition labeling and discretionary fortification
Unlike other nutrients, energy-yielding macronutrients can be used somewhat interchangeably (up to a point) to meet energy requirements of an individual. In the DRI report on macronutrients (IOM, 2002a) EARs or AIs were provided for specific macronutrients or components of the classes of macronutrients where the data were adequate to establish a causal relationship between intake and a specific function or chosen criterion of adequacy. However, for the general classes of nutrients and some of their subunits, this was not always possible; the data did not support a single number, but rather trends between intake and chronic disease identified a range. Given that energy needs vary with individuals, a specific number was not deemed appropriate to serve as the basis for developing diets that would be considered to decrease risk of disease, including chronic diseases, to the fullest extent possible. Thus Acceptable Macronutrient Distribution Ranges (AMDRs) were established for macronutrients and components as percentages of total energy intake. These are ranges of macronutrient intakes that are associated with reduced risk of chronic disease while providing recommended intakes of other essential nutrients.
Because much of this evidence is based on clinical endpoints (e.g., coronary heart disease, diabetes, cancer, obesity) that point to trends rather than distinct endpoints, and because there may be factors other than diet that may contribute to chronic disease, it is not possible to determine a defined level of intake at which chronic disease may be prevented or may develop. Therefore, an AMDR is not considered to be a DRI that provides a defined intake level. An AMDR is provided to give guidance in dietary planning by taking into account the trends related to decreased risk of disease identified in epidemiological and clinical studies.