Vitamins may harmful to certain people or under special circumstances. Antioxidants may do more help than harm for some breast cancer patients during radiation or chemotherapy treatments.

"It is possible that if you are taking concentrated high-grade antioxidant vitamins in significant doses, it may interfere with your treatment," says Dr. Marisa Weiss, the president and founder of advocacy group Breastcancer.org .

The upcoming issue of Cancer a study examines the affect high dosages of antioxidants have on breast cancer patients during chemotherapy and radiation treatment. In the study, 60.5 percent of women with breast cancer reported taking antioxidants, including vitamin E, vitamin C, beta carotene, and selenium, during their treatment.

Overall, 69.3 percent of those on antioxidants took high doses or more antioxidants contained in a Centrum multivitamin.

Chemotherapy and radiation both create free radicals within cancer cells. Free radicals damage the cancer cells, which hopefully will ultimately kill them. However, antioxidants absorb free radicals. "In cancer, we create free radical damage to tumor cells with treatment, and we want that, but antioxidants quench this damage," explains Dr. Brian Lawenda, the clinical director of radiation oncology at the Naval Medical Center, in San Diego, California.

Essentially, antioxidants may protect cancer cells from harm just like they protect normal cells. "We have lab data and some clinical data that confirms this," Lawenda says. In healthy people, antioxidants can have beneficial effects by absorbing free radicals linked to aging and other diseases.

Lawedna recommends: "Don't take a high-dose supplement of any antioxidant during chemotherapy and during radiation because we don't know what the effects will be on your treatment."

Still, other physicians believe it is too early to recommend not taking antioxidants during treatment for breast cancer patients like Heather Greenlee, N.D., Ph.D., an assistant professor of epidemiology and medical oncology at the Columbia University Mailman School of Public Health, in New York City. "We need to know if these antioxidants cause benefit or harm. There is the potential for both and we need answers."

Patients should tell their doctor about taking any antioxidants or medication or supplement that may interfere with treatment.

Please see: http://www3.interscience.wiley.com/journal/28741/home?CRETRY=1&SRETRY=0