(see Appendix B for membership), which is coordinated by the Office of Disease Prevention and Health Promotion of the U.S. Department of Health and Human Services, in collaboration with Health Canada.

Major new recommendations in this report include the following:

• A definition of a dietary antioxidant is provided.

• The Recommended Dietary Allowance (RDA) for vitamin E and selenium is the same for adult men and women regardless of age, representing the lack of specificity in data available.

• The Recommended Dietary Allowance (RDA) for vitamin C is different for adult men and women due to women's smaller lean body mass.

• α-Tocopherol alone is used for estimating vitamin E requirements and recommending daily vitamin E intake, since the other naturally occurring forms of vitamin E (β-, γ-, and δ-tocopherols and the tocotrienols) are not converted to α-tocopherol in the human and are recognized poorly by the α-tocopherol transfer protein in the liver.

• Tolerable Upper Intake Levels (ULs) for vitamin C, vitamin E, and selenium are established.

• Research recommendations for full-scale intervention trials to test the preventive potential of vitamin C, vitamin E, selenium, and β-carotene and other carotenoids for chronic disease are outlined. At the present time, there is no resolution of the possible impact of these nutrients or food components on chronic disease.

Dietary Reference Intakes (DRIs) are reference values that are quantitative estimates of nutrient intakes to be used for planning and assessing diets for apparently healthy people. They include Recommended Dietary Allowances (RDAs) as well as three other types of reference values (see Box S-1). Although the reference values are based on published data, the data were often scanty or drawn from studies that had limitations in addressing the question. Thus, scientific judgment was required for evaluating the evidence and in setting the reference values and is delineated for each nutrient in Chapter 5, Chapter 6, Chapter 7 through Chapter 8.

The process for setting the RDA depends on being able to set an Estimated Average Requirement (EAR). Before setting the EAR, a spe-