While tens of millions of us pop a daily antioxidant vitamin thinking it will lengthen our lives, an analysis of dozens of studies on the supplements is bringing questions to the actual worth of some. A new review of 68 studies on nearly a quarter-million people taking vitamins A, E, and C, and beta carotene and selenium to fight disease shows that there is no life-long benefit, and they may actually raise the risk of death.
Critics are already making accusations that the study is flawed and based too diverse a patient pool or mainly on studies of people who already had chronic illness before treatment with supplements. Other experts say it’s too early to discard all vitamin supplements as they may still have some health benefits.
The Center for Clinical Intervention Research at Denmark’s Copenhagen University Hospital, a respected organization consisting of an international network of experts that does systematic reviews of scientific evidence on health interventions, conducted this study that appears in today’s Journal of the American Medical Association.
Researchers first analyzed 68 studies involving 232,606 people, finding no significant effect on mortality in a positive or negative way connected to antioxidants.
However, after taking out lower-quality studies, researchers found a greater risk of death for those taking vitamins: 4% taking vitamin E, 7% for beta carotene, and 16% for vitamin A. The actual cause of mortality for those who died was not known. This was based on 180,938 people given either real vitamins in superdoses or recommended daily amounts, or placebo pills.
The study’s senior author, Dr. Christian Gluud of Copenhagen University Hospital said the most likely reason why those taking supplements died is from, “what people normally die from, maybe accelerated artherosclerosis, maybe cancer.”
Gluud also said that most of the studies on antioxidant supplements have resulted in no clear evidence of their health effects. “We have had this huge industry really wanting to demonstrate an intervention effect… sadly enough for the industry, and for us as consumers, it has failed to do so.”
Antioxidants are thought to fight free radicals, which are atoms or groups of atoms that are formed in a way to cause cell damage. Preliminary studies implied that antioxidants may be able to block the heart-damaging effects of oxygen on arteries, and the cell damage caused by some forms of cancer.
While experts do not dispute the health benefits of antioxidants, this new analysis suggests that they may only work when they come naturally from food rather than from supplements, or that people who eat food rich in vitamins are healthier because they take better care of themselves
Critics of the report, including Meir Stampfer, professor of nutrition and epidemiology at the Harvard School of Public Health, and Balz Frei, director of the Linus Pauling Institute at Oregon State University, claim the study and data are flawed because the pool of people studied and durations of studies were too diverse. The trials varied from a three-month study of 108 senior citizens in a nursing home to a 12-year study of 22,071 male doctors. In addition, more than two-thirds of the research looked at involved people who already had heart disease, cancer, or other risks and were taking supplements as trial treatment.
While the report concludes, “we did not find convincing evidence that antioxidant supplements have beneficial effects on mortality” and “beta carotene, vitamin A and vitamin E seem to increase the risk of death,” many experts remain skeptical and encourage further research, along with eating nutrient-rich food packed with vitamins.
Reported by Reuters and AP.