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Antioxidant Supplements Don't Cut Cancer Risk

Dec 31, 2008 | Parker Waichman Alonso LLP

Antioxidant supplements do not offer any advantage in the fight against cancer according to a study conducted at Harvard Medical School and published in the Journal of the National Cancer Institute.   This is just the latest study to question claims made by the makers of dietary supplements.

The nearly decade-long study—The Women’s Antioxidant Cardiovascular Study—involved 7,627 women taking beta carotene, vitamin C, or vitamin E in combination or individually over 9.4 years said Reuters.  The study revealed that, despite taking supplements, the women experienced no meaningful decrease in cancer risk over women who did not take supplements, reported Reuters, which noted that Dr. Jennifer Lin and colleagues conducted the clinical trial.

Medical News Today pointed out that the “randomized, double-blind, placebo-controlled” study also included researchers from Brigham and Women’s Hospital and that while this study did not reveal a link between vitamins—antioxidants—and a reduction in cancer incidence, a variety of observational studies have linked diets high in fruits and vegetables with cancer prevention. "Simply taking antioxidant supplements is insufficient to prevent cancer development," said study lead author Jennifer Lin, an assistant professor of medicine at Harvard Medical School, adding that eating fruits and vegetables rich in nutrients such as antioxidants, is still a good idea, according to Health Day News.  This is not the first time such a study has been unable to link supplements with cancer prevention, WebMD News noted.  Last month, similar results were derived from a study with male doctors taking either vitamin C or E, said WebMD News.

The 7,627 women in the recent study were cancer-free at the start of the research, said Medical News Today, and were part a larger 8,000-women group in which the women were randomly assigned to take either 500 mg of ascorbic acid—vitamin C—daily, a “natural source of vitamin E—600 IU of {alpha}-tocopherol—every other day, 50 mg of beta-carotene every other day, all three supplements, or a placebo.  The women all had or were at risk for cardiovascular disease, were over 40 years of age, and participated in the study from 1995 and 1996 until 2005—said Health Day News, which added that during the study, 624 women developed cancer and 176 died from cancer, leading the researchers to conclude that there was no "statistically significant" evidence that the supplements had any effect on a woman’s cancer risk.

Reuters reported that the risks were nearly the same in the vitamin C, the vitamin E, and the beta carotene group, with little difference in death risk in any one group; however, the risk was 28 percent higher in the vitamin C group, 13 percent lower in the vitamin E group, and 16 percent lower in the beta carotene group.  "We observed no overall associations of the three antioxidant supplements, taken singly or combined, with total cancer incidence or mortality.  Duration of supplementation also did not appear to alter the associations of these supplements with risk of cancer or mortality due to cancer," Lin and her colleagues wrote, said Reuters.

Also according to Reuters, Dr. Demetrius Albanes of the National Cancer Institute in Bethesda, Maryland discussed in an editorial on the study that two findings from the study "deserve additional mention."  It seems that vitamin E helped protect against colorectal cancer while beta carotene increased lung cancer risks, reported Reuters, which mirrors existing knowledge, noted Medical News Today.