ular attention is given throughout this report to the choice and justification of the criterion used to establish requirement values.

This approach differs somewhat from that used recently by the joint World Health Organization, Food and Agriculture Organization, and International Atomic Energy Agency (WHO/FAO/IAEA) Expert Consultation on Trace Elements in Human Nutrition and Health (WHO, 1996). That publication uses the term basal requirement to indicate the level of intake needed to prevent pathologically relevant and clinically detectable signs of a dietary inadequacy. The term normative requirement indicates the level of intake sufficient to maintain a desirable body store or reserve. In developing DRIs, emphasis is placed instead on the reasons underlying the choice of the criterion of nutritional adequacy used to establish the requirement. They have not been designated as basal or normative.

Unless otherwise stated, all values given for EARs, RDAs, and AIs represent the quantity of the nutrient or food component to be supplied by foods from the diet that are similar to those consumed by a life stage or gender group in Canada and the United States. If the food source of the nutrient is very different (as in the diets of some ethnic groups), or if the source is supplements, adjustments may need to be made for differences in nutrient bioavailability. When this is an issue, it is discussed for the specific nutrient under the heading “Special Considerations.”

As has been the practice in the past with recommendations regarding dietary allowances from the FNB (NRC, 1980, 1989a), the DRIs included in this report are intended to apply to the healthy general population. RDAs and AIs are dietary intake values that should minimize the risk of developing a condition that is associated with that nutrient in question and that has a negative functional outcome. They could not necessarily be expected to replete individuals who are already malnourished, nor would they be adequate for certain disease states marked by increased requirements. Qualified medical and nutrition personnel must tailor recommendations for individuals who are known to have diseases that greatly increase requirements, or who have increased sensitivity to developing adverse effects associated with higher intakes. Although at times these reference intakes may serve as the basis for such individual recommendations, qualified professional adaptation that is specific to each situation is necessary.

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