HOW SHOULD DIETARY GUIDANCE BE GIVEN FOR MINERAL ELEMENTS WITH BENEFICIAL ACTIONS OR SUSPECTED OF BEING ESSENTIAL

The term ultratrace elements, often used to indicate elements with an established, estimated or suspected requirement generally indicated by mu g/d, could be applied to at least 20 elements. The quality of expe rimental evidence for nutritional essentiality varies widely for the u ltratrace elements. Thus, although differing dietary guidance is appro priate for these elements, most need increased attention in future edi tions of the Recommended Dietary Allowances (RDAs) for the following r easons: (1) Increased interest in these elements by the public has bee n stimulated by the mass media; thus, responsible information about th e usefulness of the ultratrace elements for health and well being is n eeded. (2) Risk assessments and toxicological standards are influenced by the RDAs. Authorative advice is required to prevent standards that obstruct the achievement of beneficial intakes of ultratrace elements . (3) An emerging new paradigm is that the determination of nutritiona l requirements should include consideration of the total health effect s of nutrients, not just their roles in preventing deficiency patholog y; some of the ultratrace elements have identified health benefits. Si x ultratrace elements, iodine, selenium, manganese, molybdenum, chromi um and boron (and cobalt as vitamin B12), merit specific RDAs. The ter m ''estimated safe and adequate daily dietary intakes (ESADDI)'' shoul d not be used for any of the other ultratrace elements because of the misleading words ''adequate'' and ''safe.'' ''Apparent beneficial inta ke (ABI)'' seems more appropriate for the elements with beneficial, if not essential, actions that can be extrapolated from animals to human s; these elements include arsenic, fluoride, lithium, nickel, silicon and vanadium. The evidence is too limited or controversial for the rem aining ultratrace elements to even provide an ambiguous ABI. The amoun t found in a healthful diet probably should be a value provided for an appropriate intake for aluminum, bromide, cadmium, germanium, lead, r ubidium, and tin.