Risk assessment in establishing upper reference levels of nutrients

Abstract

The Food and Nutrition Board of the Institute of Medicine has undertaken a project to replace the current dietary standards (Recommended Dietary Allowances; RDAs) with Dietary Reference Intakes (DRIs) . DRIs are intended to include “a new initiative that goes well beyond the simple acute deficiencypreventing concept of RDAs” and will set dietary standards for the prevention of chronic debilitating disease and cancer. The initial phase of this project focuses on (I ) the scientific evaluation of human dietary requirements and dietary and supplement intake data for nutrients and non-nutrient food components; (2) the development of DRIs; (3) the formulation of recommendations concerning food labeling, food fortification, and other applications of dietary advice; and (4) the identification of research needs. The evaluation of DRIs includes the establishment of (I) the estimated average daily requirement, stratified by age group and gender, for a nutrient or food component and its standard deviation; (2) an RDA based on the estimated average; (3) a maximal daily intake above which the risk of toxicity increases; and (4) statistically appropriate methods to provide guidance in uses of DRIs in the assessment of dietary adequacy in populations and in the development of policy regarding feeding programs, food labeling, and food fortification. The Standing Committee on the Scientific Evaluation of Dietary Reference Intakes oversees seven nutrient-specific panels (calcium and related nutrients; folate and related nutrients; antioxidants and related nutrients; trace elements; electrolytes and water; energy and macronutrients; and non-nutrient food components, e.g., dietary fiber) and two subcommittees ( “Applications” and “Upper Reference Levels of Intake”). Each panel and subcommittee will meet four times, including once in conjunction with a workshop held to solicit the opinions of experts, practitioners, and the public. After its fourth meeting, each panel and subcommittee will develop its recommendations, which will be submitted for public review and scientific comment shortly after they are drafted. The subcommittee on Risk Assessment in Establishing Upper Reference Levels of Nutrients is charged with determining, for every nutrient and non-nutrient food component possible, the maximum levels of nutrient intake compatible with low risk, and the maximum levels of nutrient intake that will not be expected to cause adverse effects to almost all of the population ingesting that amount of the nutrient or non-nutrient food component. The public workshop associated with this subcommittee’s effort was held at the National Academy of Sciences Building in Washington, DC, on July 15 and 16, 1996. Summaries of the various scientific presentations heard by the subcommittee follow.