Antioxidant Supplements a Danger to Cancer PatientsMay 1, 2008 | Parker Waichman LLP
A recent review of clinical trial data suggests that cancer patients should perhaps avoid taking antioxidant supplements. It seems that antioxidant supplements may actually diminish the effectiveness of chemotherapy and radiation treatment in cancer patients.
Although research analyzing antioxidant use during cancer treatment has been on-going on for about twenty years, such use remains a controversial topic, noted Dr. Brian D. Lawenda, from the Navel Medical Centre in San Diego, California, and colleagues in their article in the Journal of the National Cancer Institute. Findings from different studies are conflicting; therefore, further research is still needed in order to determine whether antioxidants can be safely taken during cancer therapy and if such supplements offer any benefit.
In their research of the impact of antioxidant use on radiation therapy, the team identified three other clinical studies that specifically addressed the topic. Results from the largest of the three trials suggested that antioxidant therapy reduced overall survival; however there was other evidence that indicated that one antioxidant—amifostine—can protect certain healthy tissues from radiation damage without increasing resistance in cancerous tissue.
Sixteen trials were identified that reviewed the effects of antioxidant supplements on chemotherapy. Although there was no evidence that antioxidants reduced treatment response rates, study authors warn that none of the studies were really large enough to sufficiently address this properly. Lawenda's team concluded that, “Despite some intriguing studies that have suggested the benefit of adjunctive antioxidant treatments in cancer patients, the totality of the available evidence is equivocal at best and leaves us with serious concerns about the potential for harm.”
Meanwhile, a study last February found use of the popular antioxidant supplements beta-carotene, vitamin E, or vitamin A slightly increases a person's risk of death. The detailed analysis of human studies of beta-carotene, vitamin A, and vitamin E revealed that people who take these antioxidant supplements don't live any longer than those who don't take them. In fact, those who take the supplements have an increased risk of death. The finding was reported in The Journal of the American Medical Association from Goran Bjelakovic, MD, DrMedSci, of the University of Nis in Serbia; Christian Gluud, MD, DrMedSci, of Copenhagen University Hospital in Denmark; and colleagues. "Our findings have already changed the way I counsel my patients about antioxidant supplements," Bjelakovic said. "According to our findings, beta-carotene, vitamin A, and vitamin E cannot be recommended. I am telling them that they should stop using these supplements." "There is no reason to take anything that hasn't been proven beneficial. And these antioxidant supplements do not seem beneficial at all," Gluud said.
Kathleen Zelman, MPH, RD, LD, and director of nutrition for WebMD, said she reviewed the Bjelakovic/Gluud study for a WebMD article. "This is a very comprehensive, to-be-respected analysis. This isn't just another study coming out," Zelman says. "The bottom line is that antioxidant supplements are not a magic bullet for disease prevention. We hoped maybe they were, but they are not."