You are here:
COMPARING THE RECOMMENDED DIETARY ALLOWANCE TO TOXICITY VALUES FOR ZN, SE, MN, AND MB
Citation:
Cicmanec*, J L. COMPARING THE RECOMMENDED DIETARY ALLOWANCE TO TOXICITY VALUES FOR ZN, SE, MN, AND MB. Presented at Society of Toxicology Annual Meeting, Baltimore, MD, March 22 - 25, 2004.
Impact/Purpose:
To inform the public.
Description:
Certain essential nutrients can be toxic when ingested at dosages higher than the daily nutritional requirement. Research data for the essential trace elements, zinc, selenium, manganese and molybdenum have been reviewed by various government agencies for both their nutritional need and toxicity. The Institute of Medicine has recently published RDAs (Recommended Dietary Allowances) for 32 essential nutrients in which they provide Tolerable Upper Intake Levels as limits of safe ingestion rates for these nutrients. In a separate activity, the USEPA has derived RfDs (Reference Doses) for many of these metals since they can also be environmental pollutants in certain settings. A RfD is an upper limit of safe exposure levels for non-cancer toxicity. This presentation provides definitions for the various terms and it also provides a comparison of the methodologies that are used to establish human health values. When the contrasting nutritional need and upper limits of safe exposures of these elements are compared, the margin of safety can vary from 1.3 to 40. In some instances the safe exposure level actually is lower than the daily nutritional needs for particular age groups. This inconsistency has resulted from the use of varying methodologies and these inconsistencies will be discussed.