secular trend of earlier onset of puberty (Herman-Giddens et al., 1997), rather than differences in populations. Calculations of BMI for young adults (e.g., a median of 22.6 for Canadian women compared with 22.8 for U.S. women) resulted in similar values, indicating greater concordance between the two surveys by adulthood.

The reference weights chosen for this report were based on the most recent data set available from either country, recognizing that earlier surveys in Canada indicated shorter stature and lower weights during adolescence compared with those from surveys in the United States.

Reference weights are used primarily when setting the EAR or Tolerable Upper Level Intake (UL) for children or when relating the nutrient needs of adults to body weight. For the 4- to 8-year-old age group on an individual basis, a small 4-year-old child can be assumed to require less than the EAR and a large 8-year-old will require more than the EAR. However, the RDA or AI should meet the needs of both.

Dietary Reference Intakes (DRIs) is a generic term for a set of nutrient reference values that includes the Recommended Dietary Allowance, Adequate Intake, Tolerable Upper Intake Level, and Estimated Average Requirement. These reference values are being developed for life stage and gender groups in a joint U.S. and Canadian activity. This report, one volume in a series, covers the DRIs for vitamin C, vitamin E, selenium, and β-carotene and the other carotenoids.

AAP (American Academy of Pediatrics). 1997. Breastfeeding and the use of human milk. Pediatrics 100:1035–1039.

Atkinson SA, Alston-Mils BP, Lonnerdal B, Neville MC, Thompson MP. 1995. Major minerals and ionic constituents of human and bovine milk. In: Jensen RJ, ed. Handbook of Milk Composition. California: Academic Press. Pp. 593–619.

Beaton GH. 1994. Criteria of an adequate diet. In: Shils ME, Olson JA, Shike M, eds. Modern Nutrition in Health and Disease, 8th edition. Philadelphia: Lea & Febiger. Pp. 1491–1505.

Butte NF, Garza C, Smith EO, Nichols BL. 1984. Human milk intake and growth in exclusively breast-fed infants. J Pediatr 104:187–195.

Chandra RK. 1984. Physical growth of exclusively breast-fed infants. Nutr Res 2:275–276.

COMA (Committee on Medical Aspects of Food Policy). 1991. Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. Report on Health and Social Subjects, No. 41. London: HMSO.