Should the Recommended Dietary Allowances (RDAs) Be Revised? The Food and Nutrition Board (FNB) members discussed the RDAs with this question in mind at its summer 1992 meeting. Because members disagreed with each other about the status of the scientific data base underlying the RDAs, the need to revise the report, and whether the traditional RDA concept encompassed current knowledge about nutrition and health promotion throughout life, the FNB concluded that discussion with the nutrition communities should be undertaken. Recent symposia and publications already had begun to chart the disparity in scientific opinion about revising the RDAs (see for example: Levine et al., 1991; Sauberlich and Machlin, 1992; Williams et al., 1992; Lachance et al., 1993; Hegsted, 1993; Steinbaugh et al., 1993). With this background in mind, FNB members agreed to broaden the involvement of the nutrition communities as active partners in developing the next (eleventh) edition of the RDAs.

After further discussion and polling colleagues, the FNB organized a symposium entitled Should the Recommended Dietary Allowances Be Revised?, which was followed by a public hearing. The purpose of the symposium and public hearing was to provide an open forum to discuss the uses and possible future directions for the RDAs. Both events were held June 28–29, 1993, at the National Academy of Sciences in Washington, D.C. For the symposium, the FNB invited speakers from government agencies that rely on RDAs in their various programs, nutrition scientists from academia and industry, nutrition and dietetic practitioners, and industry and foundation representatives. After one and one-half days of invited presentations, the FNB devoted an afternoon to hearing oral statements from interested individuals. The proceedings were

recorded, and written copies of statements presented at the hearing were submitted for the record. Lists of the speakers and those presenting oral and written testimony are included in Appendix A. A summary of the presentations and oral and written testimony is provided in Appendix B. The symposium was supported by internal funds from the National Academy of Sciences and by program development funds granted to the Academy by the Kellogg Endowment Fund.

Prior to the symposium, the FNB members and staff developed five questions that formed the framework for the presentations and testimony. These questions were intended to stimulate discussion and commentary about the issues needed to move the RDA process forward. These questions, which are listed below, were included in flyers advertising the symposium.

• What has been the experience in applying the RDAs in various settings, and what factors limit their use?

• What new evidence has arisen since publication of the 10th edition of the RDAs that would argue for a change from the present values or a reexamination of the evidence?

• Should concepts of chronic disease prevention be included in the development of allowances? For which nutrients and other food components?

• How should recommended levels of intake be expressed? Should single numbers be given for different age and sex categories, or should ranges of recommended intake be provided? How should the ranges be defined? Should toxic levels be included where data are sufficient to establish an upper acceptable limit?

• Is knowledge of relationships among nutrients sufficient to consider when establishing RDAs?

The FNB was delighted with the quality of the presentations and the thoughtful nature of the comments. Despite the variety of views expressed, the speakers and testifiers unanimously agreed that the time has come to revise the RDAs.

To continue its collaboration with the larger nutrition community on the future of the RDAs, the FNB decided not to form an RDA committee at this time. Instead, it has prepared this concept paper summarizing the symposium, public hearing, and FNB discussions. In addition, this paper proposes an initial approach for revising the RDAs. There are three chapters: Chapter 1 presents a basic introduction to the RDAs. Chapter 2 includes a history of the RDAs and the conceptual changes that have taken place since the first edition in 1941. Chapter 3 outlines a new approach to the RDAs developed by the FNB. The FNB plans to disseminate this paper widely. To assist with the dissemination, the FNB has planned several symposia at nutrition-focused professional meetings (see Appendix C). Later this year, the FNB will review the comments

received in response to this concept paper and will continue the process of revising the RDAs through activities that will involve the nutrition community.

The Food and Nutrition Board (FNB) was established in 1940 to address issues of critical importance pertaining to the safety and adequacy of the nation's food supply, to establish principles and guidelines for adequate nutrition, and to render authoritative judgment on the relationships among food intake, nutrition, and health. The FNB is a distinguished, multidisciplinary group comprising scientists and leaders with expertise in various areas of nutrition, nutritional biochemistry, food science and technology, epidemiology, food toxicology, food safety, public health, and food and nutrition policy. Since its inception, the FNB has examined the science and made recommendations to improve food quality and safety, thereby promoting public health and preventing diet-related diseases. The emphasis of the FNB's activities has, over the past few years, shifted from nutritional deficiencies to excesses or imbalances in food components. The FNB additionally has become increasingly concerned with the translation of available scientific knowledge of food composition and human nutrition to the improvement of public health.

Organizationally, the FNB is a unit of the Institute of Medicine, part of the National Academy of Sciences. The Academy is a private, nonprofit corporation established by federal charter, which was created by an Act of Congress and signed in 1863 by President Abraham Lincoln. The Institute, a national organization chartered under the Academy in 1970, acts as an adviser to the federal government and, upon its own initiative, identifies issues of medical care, research, and education. The Institute secures the services of eminent members of appropriate professions to examine policy matters pertaining to the public's health.

While the 10th edition of the RDAs was in production, the administrative responsibility for the FNB in 1988 was transferred from the National Research Council, the chief operating arm of the National Academy of Sciences, to the Institute of Medicine (IOM). The IOM was then in the process of revamping its program to give greater priority to opportunities in disease prevention and the enhancement of preventive medicine in medical education and practice. Since 1988, the Institute has achieved an effective integration of FNB activities in its operations.

Janet C. King, Chair

Food and Nutrition Board

Many individuals played important roles in the initiation of the process to revise the RDAs. Special thanks go to the RDA subcommittee of the FNB (Drs. Allen, DeLuca, Dwyer, Erdman, Hambidge, and Miller), who met with me in California in September 1993 to summarize the symposium findings and to begin drafting this paper. Dr. M.R.C. Greenwood, former FNB chair, and Dr. Edwin Bierman, vice-chair, were instrumental in initiating and leading this effort. FNB staff members Drs. Bernadette Marriott and Paul Thomas and administrative assistant Marcia Lewis worked many hours under short deadlines to assist with drafting and rewriting background papers and this paper. Another important contributor to this effort was Lieutenant Colonel Margaret P. Applewhite, a Senior Service College Fellow who joined the FNB in 1993. She helped develop background papers before the symposium and summarized the diverse commentary from the symposium for this report.

In particular I want to acknowledge the many contributions of Dr. Catherine E. Woteki, the former FNB director. It was Dr. Woteki who reactivated and summarized the many discussions and concerns of this and previous Boards and obtained the funds to support the symposium.

It is an interesting and stimulating time to be chair of the FNB. I urge you to read this paper and help us, through your comments and suggestions, to develop a final plan to revise the RDAs.

Janet C. King, Chair

Food and Nutrition Board