VITAMIN E SUPPLEMENTS FOR HEART DISEASE PREVENTION REQUIRE MORE DATA
This article was originally published in The Tan Sheet
VITAMIN E SUPPLEMENTS FOR HEART DISEASE PREVENTION REQUIRE MORE DATA on the clinical benefits of the antioxidant, Daniel Steinberg, PhD/MD, University of California-San Diego, said in summarizing comments by a panel of scientific experts at FDA's public symposium on antioxidant nutrients in Washington, D.C. on Nov. 1. Steinberg, who chaired a panel on antioxidants and coronary heart disease, said that "more animal studies . . . [and] clinical trials" are needed "before we can encourage anybody to use supplements of antioxidant vitamins." The panel's comments were focused primarily on vitamin E supplementation. The panel's discussion revolved around a summary of available studies presented by Alan Chait, MD, University of Washington. Chait cited four types of evidence which, he suggested, "support the fact that antioxidants may be anti-atherogenic." Included in the evidence were in vitro studies, data from animal studies, including studies on non-human primates, epidemiological studies and limited clinical studies. Chait stressed the importance of the Nurses' Health Study and its companion study, the Health Professionals Follow-Up Study, ("The Tan Sheet" Sept. 27, p. 6), noting that these studies showed a CVD risk reduction "attributable to supplements." Panel member Eric Rimm, Harvard School of Public Health, was principal investigator of the Health Professionals study. Asked whether the panel would recommend vitamin E supplements as "a standard treatment for patients with coronary heart disease" assuming the vitamin has no side effects, Chait suggested that the side effect issue has not yet been resolved and that the cost of supplementation must also be considered. In addition, he said he "would like to see data from a . . . well-designed, placebo- controlled clinical trial that will show us that . . . we're having a positive effect with little or no risk." It would be "reasonable to recommend" the vitamin "under those conditions," he asserted. Max Horwitt, PhD, Saint Louis University Medical Center, who was scheduled to speak on Nov. 1 but could not attend the symposium, stated in a written presentation that although "toxicity of vitamin E has, so far, not proved to be a problem," he "remains cautious." Horwitt suggested that "very high levels of antioxidants in blood and tissues may make them pro-oxidants." Rimm presented the concern that an antioxidant health recommendation could be viewed as a "panacea," and that at-risk patients might "forget about everything else that we've already established as coronary risk factors." If presented with more clinical trial evidence, however, Rimm said he would consider recommending vitamin E supplements to patients "as part of a healthy lifestyle." However, panel member Balz Frei, PhD, Harvard School of Public Health, asserted in an impromptu presentation to the symposium the next day that the panel was generally in favor of a health claim and that the wrong question was directed at the group. Frei said he was responding to a morning-after summation of the panel's deliberations by FDA Office of Special Nutritionals Acting Director Elizabeth Yetley, PhD. In opening the Nov. 2 session of the symposium, Yetley indicated that her interpretation of the panel's position was that a health claim may be "premature" for antioxidants "until the completion of good clinical trials." Suggesting that the panel chairman's questions "were a little bit off target," Frei maintained that the panel should have been asked whether "antioxidants may lower the risk of heart disease." Instead, he continued, the panel was asked to discuss whether the available evidence supports the question -- "do antioxidants lower the risk of heart disease." For that question, he acknowledged, "we really need clinical trials. However, Frei said he believed that "there is substantial scientific agreement that antioxidants may lower the risk of heart disease" and that he "would certainly support that statement." The antioxidant/CVD panel was one of six panels given the charge by FDA to review the existing scientific data on antioxidant nutrients and one of the few panels that expressly discussed the use of antioxidant supplements. A panel charged with discussing the role of vitamin E in preventing cancer risk was leery of recommending supplements as potential chemopreventive agents. When the issue of antioxidant supplements was raised, panelist Jeffrey Blumberg, PhD, USDA's Human Nutrition Center on Aging, objected to a focus on supplements, adding that the purpose of the panel was to discuss "a potential health claim for antioxidants not . . . antioxidant supplements." He noted that the goal of "the public health policy is to get people to consume more antioxidants . . . not argue whether a vitamin E supplement is the answer." Instead, Blumberg maintained that it is important to view the "totality of evidence for CVD and cancer" and vitamin E because it reveals benefits that "are not necessarily attributable only to supplementation." With respect to a claim for vitamin E and cancer risk reduction, several panelists expressed doubt that the current data supported a claim. Ann Kennedy, University of Pennsylvania School of Medicine, said she was concerned with the "marginal effects" found with vitamin E in studies in humans. Kennedy said she "would like to see a far bigger effect" before recommending a health claim. Orville Levander, PhD, USDA's Human Nutrition Research Center, said the data suggest that "vitamin E probably has at best an equivocal role in human cancer prevention." Other panelists disagreed, however, and supported a potential health claim. John Weisburger, PhD, Naylor Dana Institute, proposed that he would "vote very strongly for recommending 100 units/day [of vitamin E] for people at risk." Gerald Shklar, Harvard School of Dental Medicine, said that "we have very persuasive evidence epidemiologically that vitamin E does have a cancer protective effect." Although the panelists disagreed on the issue of a specific vitamin E health claim, they concurred that a claim recommending a "diet balanced rich in vitamins and nutrients" would "lower the risk of heart disease and cancer," panel chairperson Julie Buring, DSc, Brigham and Women's Hospital, concluded at the end of the panel discussion.
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