Deliberations and evaluations of the approaches, endpoints and paradigms for boron, chromium and fluoride dietary recommendations.

The 10th edition (1989) of the Recommended Dietary Allowances provided estimated safe and adequate daily dietary intakes (ESADDI) for chromium and fluoride and summarized the substantial evidence for boron essentiality in animals. New endpoints, approaches and paradigms to use to formulate dietary guidance for these elements were reviewed by a discussion group that met as part of a national workshop. Deliberations of the group are summarized to facilitate future discussions on dietary guidance for these elements. The category, "provisional RDA" was recommended to replace the current ESADDI category because of the ambiguities associated with the ESADDI. A provisional RDA would be defined for a dietary substance that meets one of two sets of criteria: class 1, clear evidence of essentiality but uncertain or limited quantitative data or endpoints to define dietary requirements; and class 2, strong evidence of essentiality, and clear nutritional benefit based on reasonably certain quantitative data, but lack of clear information on function or endpoints to use for deficiency dietary requirements. A summary of background information and possible approaches for assigning provisional RDAs for boron, chromium and fluoride is presented.