ANTIOXIDANT SUPPLEMENT RELATIONSHIP TO DISEASE PREVENTION CALLED "PREMATURE"
This article was originally published in The Tan Sheet
ANTIOXIDANT SUPPLEMENT RELATIONSHIP TO DISEASE PREVENTION CALLED "PREMATURE" based on the lack of efficacy data on supplements by researcher Norman Krinsky, PhD, Tufts University School of Medicine, at FDA's Nov. 1-3 conference on antioxidants in Washington, D.C. Following a Nov. 3 session on how to determine whether significant scientific agreement exists on a health claim, Krinsky observed that "it turns out that we have after this two- and-a-half days very little information presented about the efficacy of dietary supplements." Krinsky, who participated in a Nov. 2 panel on beta carotene and cancer, acknowledged that "there has been substantial information that there is a relationship between these [antioxidant] vitamins and the risk of cancer or cardiovascular disease." However, he noted that "the real issue deals with the standard for dietary supplements." There is a "very small number of studies in which dietary supplements have actually been evaluated." "Whereas I think that the relationship . . . has been clearly evaluated with respect to diet or the dietary antioxidants," Krinsky concluded, "I think the issue with respect to dietary supplements is still premature and I hope that the FDA will take this into consideration." Krinsky added that "we're in the midst right now of a whole list of studies that involve dietary supplements." While several researchers participating in the conference agreed with Krinsky that there are not adequate data to draw a connection between antioxidant supplements and cancer/cardiovascular disease, many indicated that they personally use dietary supplements. This led FDA Office of Special Nutritionals Acting Director Elizabeth Yetley, PhD, to remark that the "scientific community . . . needs to explain what appears to be a contradiction -- Why is the science good enough for scientists but not for the general public?" In an informal Nov. 2 presentation, Balz Frei, PhD, Harvard School of Public Health, questioned the FDAer's inference that the data is "good enough for the scientists but not for the public." Frei said he believes that the data "is good enough for both the scientists and the public if you are talking about" antioxidants lowering the risk of heart disease. Taking a different tack, Louise Canfield, PhD, University of Arizona, argued that researchers' consumption of dietary supplements should not be used "as a way of determining consensus among scientists" about health claims for antioxidants. Although polling scientists on their supplement intake is "an interesting survey or an interesting kind of parlor game to indulge in," Canfield said, "I don't think that's an appropriate way for us to find out what we think about recommendations for supplements." She added: "I also don't think that any scientist that I know of is consciously withholding any data from the public" on the benefits of antioxidants. Researchers at the conference also expressed concern with using the term "antioxidant," because, as expressed by Diane Birt, PhD, University of Nebraska Medical Center, "the word 'antioxidant' implies a mechanism [of action] and we don't know the mechanism." Scientists "need to find a better term," she added. Krinsky agreed that the term "antioxidant" is "really not an appropriate term." On a related issue, Julie Buring, ScD, Brigham and Women's Hospital, said that she has "become increasingly uncomfortable with . . . talking about all antioxidants as a group." Referring to the effects of antioxidants in general "impl[ies] that all antioxidants are interchangeable," and the effects of one will be the same for all. She asserted that the "strongest evidence" supporting a beneficial effect of antioxidants is the association between beta carotene and lung cancer. "The other antioxidants," she maintained, "don't appear to have the kind of evidence behind them that I would hope."
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