The National Academies Process for Establishing DRI Values

The Dietary Reference Intakes (DRIs) are a set of reference values that, when adhered to, predict a low probability of either nutrient inadequacy or excessive intake. The process for deriving DRIs is more rigorous and transparent now than when first developed. This is an outcome of a more rigorous and systematic approach to identifying evidence, the introduction of bias assessment methodologies, updated food and nutrient databases, data on cultural and context-specific dietary patterns, and better metabolic markers of nutritional status. The DRI model was developed with the concept of including both non-chronic and chronic disease endpoints in deriving reference values. In practice however the derivation of reference values for chronic disease endpoints was more challenging. This is largely due to a model based on the concept of assuring intake adequacy, the RDA, and an upper limit threshold, the UL, based on adverse health outcomes rather than chronic disease risk. To address this, a new category of DRI value, the CDRR was developed which considers the characteristics of chronic disease development in identifying a causal relationship between nutrient exposure and an adverse health outcome rather than adequacy or toxicity. The challenge, however, is that the latency between dietary exposure and a chronic disease outcome makes it difficult to show causality. Thus, adapting the CDRR model to meet the needs of the general population in the current context suggests a need to redefine the boundaries that describe the health of the population and to re-examine how indicators of chronic disease can be integrated into the DRI process. Moving forward, the DRIs will continue to adapt to a changing health environment and application of the CDRR value will be considered in future DRI reviews, particularly those for macronutrients.