Maintaining Dietary Reference Intakes

An important part of the DRI process is continually improving the DRI framework and the methods used to derive reference values. The Joint Canada-U.S. Dietary Reference Intakes Working Group undertakes activities, on behalf of both countries, to enhance the DRI process and inform future DRI reviews. 

Standing Committee to Review the DRI Framework

The NASEM Standing Committee to Review the DRI Framework is developing a series of short reports on DRI-related issues.

These NASEM reports respond to questions brought forward by the DRI working group on topics such as how to: 

  • Derive DRI values
  • Ensure a consistent approach across DRI reviews

The standing committee started this work in 2022 and will continue for several years. Insights from the standing committee reports will inform future DRI reviews, including the ongoing DRI macronutrient review.

Evidence Scanning to Support the Review of DRI Values

Having the appropriate evidence available is critical to developing DRI values.

DRI values are informed by objective, systematic evidence reviews. These assess the strengths and limitations of the total evidence available on adequacy, potential toxicities, and risk of chronic disease. Not all nutrients have the level of evidence available that warrant this type of review.   

The time and cost to complete a systematic review are high. The DRI working group identifies and prioritizes topics for systematic review by evidence scanning. This allows for an initial assessment of the evidence base to:

  • Identify whether sufficient new evidence exists
  • Decide if undertaking a systematic review is appropriate  

Evidence Scanning to Support Reviews of Macronutrients and DRI Values

The scope of the macronutrient review is large and complex. The DRI working group plans to review all types of values for all the macronutrient components. However, the availability of relevant new data for setting DRI values will determine: 

  • How the macronutrient reviews are prioritized 
  • Whether a change to an existing DRI value is warranted 

The DRI working group uses evidence scanning to help determine where systematic reviews may be needed to support undertaking a review of current macronutrient DRI values. 

Evidence Scanning to Support Reviews of Other Nutrients

The DRI working group used evidence scanning to assess the new evidence available since the last DRI review for:

  • Thiamin
  • Riboflavin 
  • Phosphorus 

These were used as case studies to help confirm the usefulness of the evidence scanning process and to refine the approach.

The results of these evidence scans indicate that there aren’t enough significant, new, and relevant data to undertake a new review of DRI values for these nutrients.