was determined that an EAR for calcium could not be established at the present time. The recommended AI represents an approximation of the calcium intake that, in the opinion of the DRI Committee and its Panel on Calcium and Related Nutrients, would appear to be sufficient to maintain calcium nutriture while recognizing that lower intakes may be adequate for many; however, this evaluation will have to await additional studies on calcium balance over broad ranges of intakes and/or of long-term measures of calcium sufficiency.
The AI is the intake value that appears to be needed to maintain, in a defined group of individuals with limited but uncertain sun exposure and stores, serum 25-hydroxyvitamin D concentrations above a defined amount. The latter is that concentration below which vitamin D deficiency rickets or osteomalacia occurs. The intake value was rounded to the nearest 50 IU, and then doubled as a safety factor to cover the needs of all, regardless of exposure to the sun.
The AI is the intake value that reduces the occurrence of dental caries maximally in a group of individuals without causing unwanted side effects. With fluoride, the data are strong on risk reduction, but the evidence upon which to base an actual requirement is scant, thus driving the decision to adopt an AI as the reference value.
The DRIs represent a new paradigm for the nutrition community: three of the reference values are defined by a specific indicator of nutrient adequacy, which may relate to the reduction of the risk of chronic disease or disorders; the fourth is defined by a specific indicator of excess where one is available. In the previous paradigm, the indicator of adequacy was usually limited to a classical deficiency state. Since the publication of the last revision of the Recommended Dietary Allowances in the United States (NRC, 1989a), the Canadian Recommended Nutrient Intakes (Health Canada, 1990), and the report on Diet and Health (NRC, 1989b), the research base related to the role of diet in chronic disease has expanded sufficiently to permit moving beyond deficiency indicators to other indicators with