RDA "CONCEPT" PAPER WILL BE PUBLISHED FOR COMMENT IN "EARLY 1994"
This article was originally published in The Tan Sheet
RDA "CONCEPT" PAPER WILL BE PUBLISHED FOR COMMENT IN "EARLY 1994" in order to start the process of revising the current edition of the Recommended Dietary Allowances, Food & Nutrition Board Deputy Director Bernadette Marriott, PhD, told the Council for Responsible Nutrition's annual conference in Washington, D.C. on Sept. 22. Marriott reported that a group of Food & Nutrition Board (FNB) members held its first meeting to prepare the concept paper during the week of Sept. 13 and will meet "over the next few months to draft this new conceptualization." Asked when the next RDA edition would be published, Marriott replied that she could "not give an answer to that." However, she predicted that the concept paper would "come out hopefully in January" in an as yet unnamed scientific journal. She also indicated that FNB plans to address the current folic acid RDA for women prior to the publication of the next RDA edition. Marriott reported that FNB has decided "that it will entertain a reconceptualization of the RDA from the ground up with a disease prevention approach." She indicated that FNB is even considering whether to move away from RDAs as the name for its nutritional recommendations. The RDA concept paper is an outgrowth of a workshop held by the National Academy of Sciences' FNB in late June ("The Tan Sheet July 5, pp. 11-15). FNB is re-evaluating its historical approach to RDAs based on nutritional deficiency in light of recent studies that have shown that higher than RDA levels of some nutrients, particularly antioxidant vitamins and folic acid, have a preventative benefit against cardiovascular disease, cancer and birth defects. At a one-day meeting following the workshop, the board developed its plan of action, Marriott said. In addition to the concept paper, the board decided "not to establish an RDA committee at this time but . . . to continue the national scientific dialogue begun at [the workshop] for another year." Traditionally, FNB has appointed a committee of nutritional experts to collect and review new scientific data for each new edition of the RDAs. The current edition -- the tenth since the first RDAs were established in the early 1940s -- was published in 1989. Marriott said the scientific dialogue in preparation for the eleventh edition will be fostered through speaking engagements by representatives of the FNB to constituent groups, such as CRN, and through discussion workshops at major scientific meetings over the next year. In addition, the board decided to "consider developing a range of values for nutrients and a more specific statement about an upper acceptable limit," Marriott said. FNB also agreed that "whatever is developed should have more information on nutrient interactions where the data is available." FNB plans to establish a now committee that will direct its attention on the specific nutrient requirements of the elderly, Marriott reported. The committee will prepare a separate report, she said, focusing "on nutrient needs for basically healthy older individuals who may have chronic diseases but through medication are maintaining active lives." Marriott noted that if RDAs are broadened to cover chronic disease prevention, "then additional types of data will need to be reviewed and evaluated." For example, she added, "an assessment of the strength of the data" in support of each nutrient's role in disease prevention "would need to be made." Some of the criteria that will be used in evaluating the data by FNB include: the strength of association between a nutrient and disease prevention "often expressed as relative risk"; a dose response relationship; demonstration of "a temporally correct association"; "consistency of association in a variety of studies"; "specificity of association"; and "biological plausibility," Marriott said. Marriott also raised a number of other issues that would need to be addressed before the scope of RDAs is expanded, such as: whether levels of intake should be based on nutrient function or other functions; what database and criteria should be used if other functions are assessed; the desirable level of intake over a lifetime and whether such levels can be determined in the absence of clinical trial data; and whether levels should be expressed in terms of ranges, dietary patterns, numerical goals or some other measurement. Acknowledging that FNB has been criticized for being "too conservative," Marriott pointed to the use of RDAs as the basis for dietary guidelines in a number of federal programs, including the Special Supplemental Food Program for Women, Infants and Children. In response to a question regarding the historically closed process in which RDAs have been set in the past, Marriott indicated that times have changed for FNB. "We want this to be an open process," she stated. "At some point there will be a committee established necessarily to pull the information together to review the literature. It is not going to be a committee that is going to go away behind closed doors. They are going to have public meetings throughout the country and we are very sincere in saying we want your response to our concept when we develop it."
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