RDA REVISION BASED ON LONG-TERM STUDIES ON OPTIMAL HEALTH EFFECTS

RDA REVISION BASED ON LONG-TERM STUDIES ON OPTIMAL HEALTH EFFECTS is advocated by Gladys Block, PhD, University of California-Berkeley, at a June 28-29 public hearing of the Food and Nutrition Board (FNB) of the National Academy of Sciences in Washington D.C. Calling the criteria on which the Recommended Daily Allowances are based "inadequate," Block, a former researcher for the National Cancer Institute, urged FNB to look at long-term measures of adequacy and to use recent epidemiology data to calibrate optimal nutrient intake. "The idea that we've been reflecting adequacy for long-term health based on the methods we've been using is simply incorrect," Block declared. "That adequacy has to do with maintaining optimal or reasonably good health throughout the course of lifetime, [but] we haven't been using methods that are capable of detecting long- term health outcomes," Block said. Block added that the current RDA standard "ignores the fact that all of us are cardiovascular disease, and cancer, and cataracts, and a host of chronic diseases of aging waiting to happen." In the past, a central criterion for determining RDAs was the levels of intake of "apparently healthy people." Block asserted that the criterion translated into subjects who were merely "symptomless." Block also complained that the RDAs looked only at unifactorial studies, failing to account for the multifactorial nature of age-related diseases. "Where does the burden of proof lie?" Block asked the group. "I suggest the burden of proof should be on those who say that less is adequate, instead of on those who say that more is beneficial. Err on the side of public health." Focusing her talk on the benefits of antioxidants, which Block called "as important as the germ theory," Block stressed the importance of the human "physiologic economy" in resisting cell damage. Citing medical literature on the role of oxidation "in virtually every disease or condition," Block maintained that the human immune system needs increasing amounts of antioxidative nutrients with age, a requirement that is ignored by the RDA standards. Block said that those standards are currently unable "to keep us in reasonably good health through our entire lifespan, so that we don't die prematurely." "The [younger] body could probably repair virtually 100% of the [oxidative] errors, but it costs to be that perfect, and so the body repairs most, but it can't repair all, and the result is that DNA damage builds up," Block said. As a result, the nutrition levels recommended by the FNB are sufficiently protective only through our "reproductive years," according to Block. In contrast, "the public believes that these numbers mean, 'This is adequate for my lifetime,'" Block said. Echoing Block's view on public interpretation of RDAs, Pharmavite CEO Kenneth Rosenberg explained that because of the governmental imprimatur carried by RDAs, "consumers have probably drawn some inappropriate conclusions about just what these RDAs mean for them . . . Most consider and perceive these values to represent an ideal goal, translated by them into personal best." Charging that "deficiency diseases . . . have basically not been a public health problem in the U.S. for decades," Rosenberg concluded that "promotion of optimal health should be a priority." The dietary supplement CEO suggested that if FNB did not set optimal levels of nutrient intake, consumers would lack a responsible source of information. Rosenberg said that although "ideally, consumers would get information about nutrition and health from their physician . . . the medical profession is generally ill-equipped and generally uninterested in providing nutrition information. The problem starts with the lack of nutrition education in medical school," he maintained. FNB's best response, according to Rosenberg, would be to focus on "the long-term impact" of dietary intake, to the point of making recommendations on the basis of data that "may not yet be conclusive in terms that scientists would ideally like it to be." Success for a revised set of RDAs would hinge on the creation of a new paradigm for scientific standards, asserted Hoffmann-La Roche Associate General Counsel Anthony Iannarone. Characterizing nutrition as a "relatively new science," Iannarone said that the field involved "many variables, individual differences, and confounding factors. Therefore, those who expect this science to produce mathematically precise answers and conclusions clearly expect too much." Strict adherence to scientific standards should instead "give way to some extent to practical realities," Iannarone said. Because "the impact of the RDAs on government policy can no longer be ignored," Iannarone added that the NAS board should question whether its recommendations were adequate as a "touchstone for devising government feeding programs, as well as a cornerstone for surveys used to determine the nutritional status of the American populace." Center for Science in the Public Interest Associate Nutritionist David Schardt similarly urged FNB to not be "paralyzed in acting now by the prospect that these allowances might be advisable sometime, somewhere, for some subpopulation group." "Rather," Schardt said, "we should first identify those who might benefit from these allowances and then identify those who might not." Schardt also asked the board to establish upper safe intake levels based on a literature review. He said that these levels would be a key element in nutritional supplement labeling. Devising safe upper intake levels for vitamins and minerals was proposed by FDA in an advanced notice of proposed rulemaking on the regulation of dietary supplements ("The Tan Sheet" June 21, p. 1). By attempting to establish nutrient levels which more aggressively promote optimal health, FNB would also stimulate research into nutritional science, Schardt alleged. Schardt noted that his group was working with Congress on legislation which would "encourage such research."