A study published in the Oct. 2, 2004, issue of the British medical journal The Lancet concludes that antioxidant supplementation has no positive impact on gastrointestinal cancer prevention and may actually increase mortality among users.
The study, a meta-analysis of previous studies regarding antioxidants and cancer, quickly came under fire from supplements industry groups. The Council for Responsible Nutrition issued a press release questioning both the study?s methodology and the manner in which The Lancet presented the authors? findings.
The journal was recently redesigned to feature prominently on the cover a quotation from one of the published articles. In this issue, the quotation is taken from the commentary on the antioxidant study, and reads: ?The prospect that vitamin pills may not only do no good but also kill their consumers is a scary speculation, given the vast quantities that are used in certain communities.?
?You have to see the cover to understand our outrage about it,? said Judy Blatman, vice president of communications for CRN. ?It?s certainly a departure from what we?re used to seeing in scientific journals. The Lancet is a respected scientific publication, and we don?t expect them to turn themselves into a tabloid. It?s a sad state of affairs for science.?
According to Blatman, CRN also objects to the content of the quote, which suggests that vitamins may be dangerous. ?Even the authors of the commentary point out that the results are preliminary, and that the mortality analysis is a work in progress and does not offer proof of hazard,? she said.
The studies chosen for The Lancet?s meta-analysis each are related to only a single antioxidant. ?The human antioxidant system represents a complex scenario of interacting components,? said Michael Murray, N.D., director of product development for Natural Factors Nutritional Products, based in Coquitlam, British Columbia, Canada. ?It is unlikely that any single antioxidant would be proven effective. Most antioxidants require the presence of a myriad of ?partner? antioxidants that allow them to work more efficiently.?
John Hathcock, Ph.D., vice president for scientific affairs at CRN, said that the methodology of the study—in which the effects of different supplements were compared—violates one of the primary rules of meta-analysis. Pointing out that selenium had been found to have some effect in cancer prevention, Hathcock said, ?The studies have to be combinable. If you combine a negative event of beta-carotene and a positive event of selenium, they offset each other. It?s like averaging a fat person and a thin person and concluding that they?re of ideal weight.?
But some in the industry see the negative spin of the Lancet cover quote as the flip side of the positive spin routinely given to supplements studies by industry groups such as CRN. ?The quote on The Lancet is indeed taken out of context,? said Anthony Almada, president and chief science officer of Laguna Niguel, Calif.-based ImagiNutrition. ?But if the study came out positive, I?m sure the industry would pull a quote that made it seem more positive than it actually was. There?s a double standard on both sides of the fence, both by the media and by the supplements industry.
?There is an a priori assumption among users and marketers of supplements that antioxidants increase or promote health,? Almada said. ?This is a passionate, evangelical position based on faith, not on facts. The evidence to date, in its totality, does not support that the supplements that have been tested indeed prevent cancer.?
Murray, who supports the use of antioxidant supplements, said, ?While diets rich in antioxidant nutrients have consistently shown tremendous protection against cancer and heart disease, clinical trials utilizing antioxidant vitamins and minerals have produced inconsistent results.?
Natural Foods Merchandiser volume XXV/number 11/p. 7, 12