DELIBERATIONS AND EVALUATIONS OF THE APPROACHES, END-POINTS AND PARADIGMS FOR DETERMINING ZINC DIETARY RECOMMENDATIONS

The work group considered past and future Recommended Dietary Allowanc es (RDAs) for zinc. Past RDAs were based in large part on metabolic ba lance data. Balance measurements are technically difficult and it is u ncertain that they reflect true requirements. Therefore other methods should be used to determine requirements and the RDA. The best approac h at this time is the factorial method. In the future, data from measu rements of zinc kinetics, in relation to diet and physiological functi ons will provide useful insights. Future RDAs should provide for at le ast three levels of bioavailabilty: low, moderate and high. Whether ad justments should be made in the RDA to account for life style factors is a matter of philosophy. The importance of the differences (gaps) be tween the RDA and usual intakes of zinc by persons who are apparently in good health, or between the RDA and other dietary guidelines, is an issue for consideration.