Wednesday, August 15, 2007

Are antioxidants worthless against heart disease?

Are antioxidants worthless against heart disease? By Neil E. Levin, CCN, DANLA 8/15/07 In a published report, A Randomized Factorial Trial of Vitamins C and E and Beta Carotene in the Secondary Prevention of Cardiovascular Events in Women (Results From the Women’s Antioxidant Cardiovascular Study), researchers concluded that, “There were no overall effects of ascorbic acid (vitamin C), vitamin E, or beta carotene on cardiovascular events among women at high risk for CVD.” (1) This is simply untrue. In order to reach that conclusion, the researchers had to count non-compliant subjects as taking vitamin E, even when it was obvious that they weren’t following the study protocol. Is that intellectually honest? I would have given the opposite conclusion. When subjects assigned to take vitamin E actually took their vitamin E, the results were significant and proved that the vitamin had benefits: “Censoring participants on noncompliance led to a significant 13% reduction in the primary end point…Reductions in secondary study end points were also stronger, with a 22% reduction in MI … a 27% reduction in stroke … and a 9% reduction in CVD mortality … There was a 23% reduction in the combination of MI, stroke, or CVD death…Among those with prior CVD, the active vitamin E group experienced fewer major CVD events …” [-11%] "A marginally significant reduction in the primary outcome with active vitamin E was observed among the prespecified subgroup of women with prior cardiovascular disease (RR, 0.89; 95% CI, 0.79 - 1.00 [P = .04]; P value for interaction = .07). There were no significant interactions between agents for the primary end point, but those randomized to both active vitamins C and E experienced fewer strokes (P value for interaction = .03)." Why did the researchers gloss over these admitted benefits (that those assigned to take vitamin E who actually did take it had "significant" benefitsand those with prior CVD who took the relatively low levels of C plus E experience fewer strokes)? This was wholly ignored in the study's conclusion, as well as the subsequent press release and extensive news coverage. I have found and published (2) criticisms of this particular failing (reaching improper conclusions not truly supported by the data) before: (3-10) REFERENCES: 1. Cook N, et al. A Randomized Factorial Trial of Vitamins C and E and Beta Carotene in the Secondary Prevention of Cardiovascular Events in Women. ARCH INTERN MED. VOL 167 (NO. 15), AUG 13/27, 2007 2. Levin N. Land of Confusion: How Poor Science and Misleading Media Coverage Create Public Confusion About How Dietary Supplements Affect Health. J App Nutr, Vol 55, No. 1, 2005 8-15 3. Edgar R. Miller, III, MD, PhD; et al. High-dose vitamin E supplementation may increase all-cause mortality, a dose response meta-analysis of randomized trials. Annals of Internal Medicine: Online: Nov. 10, 2004: Print: 4 January 2005 | Volume 142 Issue 1 4. A study conducted by USA Today found that more than half of the experts hired to advise the government on the safety and effectiveness of medicine had a direct financial interest in the drug or topic they were asked to evaluate. An analysis of financial conflicts of interest at 159 FDA advisory committee meetings from January 1, 1998, through June 30, 2000, found that at 92% of the meetings, at least one member had a financial conflict of interest, while at 55% of meetings, half or more of the FDA advisers had conflicts of interest. These conflicts included helping a pharmaceutical company develop a medicine, then serving on an FDA advisory committee that judges the drug. 5. Lonn E, et al. Effects of long-term vitamin E supplementation on cardiovascular events and cancer: a randomized controlled trial. JAMA. 2005 Mar 16;293(11):1338–47. PMID: 15769967 6. Blumenthal M, Farnsworth NR. Echinacea angustifolia rhinovirus infections [letter]. N Engl J Med. Nov.3, 2005;353(18):1971–1972. 7. 21 C.F.R. Pt. 119, Final Rule Declaring Dietary Supplements Containing Ephedrine Alkaloids Adulterated Because They Present an Unreasonable Risk (Published February 11, 2004) (Effective April 12, 2004) available at 8. Taylor JA, Weber W, Standish L, Quinn H, Goesling J, McGann M, Calabrese C. Efficacy and safety of Echinacea in treating upper respiratory tract infections in children: A randomized controlled trial. J Amer Med Assn Dec 3, 2003;290(21):2824–30. 9. Fugh-Berman A, Myers A. Citrus aurantium, an ingredient of dietary supplements marketed for weight loss: current status of clinical and basic research. Exp Biol Med (Maywood). 2004 Sep;229(8):698–704. Review. PMID: 15337824 10. Effects of Long-term Vitamin E Supplementation on Cardiovascular Events and Cancer. JAMA. Vol. 293 No. 11, Vol. 293 No. 11, March 16, 2005