There have been some recent sensational media stories reporting increased risks of early mortality from the consumption of antioxidant vitamins. The scientific review to which these sensationalistic stories refer was a meta-analysis in the Cochrane Database of Systematic Reviews published in April 2008.
The review, written by Goran Bjelakovic of Copenhagen University Hospital, in Denmark was an update of an earlier report published in the Journal of the American Medical Association in February of 2007. The JAMA report received considerable criticism from research scientists familiar with antioxidant research.
They reviewed the published evidence prior to 2005 on beta carotene, vitamin A, vitamin E, Vitamin C and selenium. The overall conclusion of the study was that on balance, the best quality research showed that beta carotene, vitamin A and vitamin E may increase mortality risk, but vitamin C and selenium need further study. The mortality risk data included “All Cause Mortality” and that means it included death from car accidents, drowning and other age related issues.
Meta Analysis studies are a collective review of a large number of studies (like pooling all the results into a single study) to assess a scientific trend and presumably to offer some guidance to future research. These studies are always open to criticism because they have to establish a criterion of what studies to include. Studies differ in dosage, source of supplements, data collection methods, duration of the study and the relative health and age of the participants.
In the Cochrane Database meta-analysis they reviewed 67 clinical trials but for some reason ignored or excluded some 750 other studies including 405 where no deaths were reported.
Dr. Bjelakovic is well known for his skeptical attitude towards dietary supplements. In 2007, he co-authored an article in the Journal of the National Cancer Institute entitled: “Surviving Antioxidant Supplements” and has posted an article on a newspaper syndicate entitled “Do antioxidant supplements work?”
There is almost universal agreement by the scientific community that vitamin A does not act as an antioxidant but vitamin A studies were included in this analysis.
There was no scientific connection or mechanism made as to how antioxidants might increase risk of mortality. It is basically a “guilt by association” conclusion.
There is a large body of evidence that supports antioxidant supplements as an important role in maintaining and promoting overall health.
Healthy consumers who are using antioxidant supplements in the manner that they were meant to be used—as complements to, not in place of—other healthy lifestyle habits, can continue to feel confident in the benefits these supplements provide.
It may be of interest that numerous studies appeared in the scientific literature in the past year that demonstrate antioxidants have a favourable influence on health and well being but they were not reported by the large scale popular media.