Perspective: Appraisal of the Evidence Base to Update DRI Values-Lessons from the Past, Thoughts for the Future.

Updating evidence-based nutrient guidance is challenging. One set of recommendations for which a robust evidence base is essential is the DRIs. In the past 10 y, DRI values for 4 essential nutrients have been re-evaluated in 2 groups: vitamin D and calcium, and sodium and potassium. To support the work of the committees tasked with evaluating the available evidence, the federal agencies that sponsor the DRI reviews contracted with the Agency for Healthcare Research and Quality to perform systematic reviews on predefined questions for these nutrient groups. Our aims were to tabulate the studies included in these systematic reviews and then, within the context of prespecified outcomes, summarize the totality of the available evidence and identify areas for consideration to maximize the value of the end products for future DRI committees. For the outcomes of interest, the available studies did not tend to report age data consistent with the current DRI categories. For some life stage categories, particularly pregnancy and lactation, there is a dearth of data. A wide range of study interventions were used, making it challenging to combine data to accurately derive or re-evaluate DRI values. There is also an under-representation of data on race/ethnicity and overweight/obesity, which is of concern, given the shifting demographic in the US and Canadian populations. Moving forward, it may be advantageous to develop a process to prospectively target research funding for studies designed to generate data that will most closely support re-evaluation of DRI values.