The study reviewed here found that many women being treated for breast cancer are taking at least one antioxidant supplement, often at levels much higher than recommended in a healthy diet. The researchers looked at four antioxidant supplements:
Because the effects of antioxidant supplements on specific breast cancer treatments hasn't been thoroughly studied, this suggests that more research is needed.
Antioxidants are compounds found in fruits, vegetables, nuts, grains, and some meats, poultry, and fish. Antioxidants may help protect cells from substances called free radicals. Free radicals are produced when you're exposed to some pollution such as tobacco smoke. Your body also produces free radicals when it breaks down food. Free radicals can damage cells and may contribute to certain diseases, including cancer. Some research has suggested that antioxidants may help reduce the risk of cancer, heart disease, and age-related changes in the body. Still, it's not clear if taking antioxidant supplements at higher-than-recommended levels offers more benefits than getting the recommended amount of antioxidants from the foods you eat. Taking certain supplements at higher-than-recommended levels can cause health problems.
There are some concerns that taking antioxidant supplements during cancer treatment can interfere with certain treatments. For example, radiation therapy and certain chemotherapy medicines work by producing free radicals that attack cancer cells. Since antioxidants destroy free radicals, some doctors think taking antioxidant supplements might reduce the effectiveness of the treatment. Many oncologists tell patients not to take antioxidant supplements during treatment.
More than 760 women diagnosed with non-invasive and invasive breast cancer in 1996 and 1997 were asked about their use of four antioxidant supplements during adjuvant treatment. Adjuvant treatments are given after surgery to reduce the risk of the cancer coming back. Almost 87% (663 women) received one or more of the following adjuvant treatments:
More than 60% of the women took at least one antioxidant supplement while on adjuvant treatment.
Most of the women (69%) who took antioxidant supplements during treatment took higher-than-recommended doses. The researchers considered a higher-than-recommended dose to be more of the antioxidant than in a Centrum multivitamin.
If you're being treated for breast cancer, you may be thinking about taking or are already taking supplements such as antioxidants to do all that you can to fight the cancer and keep it from coming back. It might be fine to do this, but it's very important to tell your doctor about ALL the supplements and medicines you take, including over-the-counter medicines and vitamins. Make sure you tell your doctor the exact dose of each supplement, vitamin, or medicine you take or are thinking about taking. Your doctor may have concerns about how these medicines and supplements may interact with your treatments or how they may affect your health. Just because you can buy a medicine, vitamin, or supplement without a prescription doesn't mean it's safe for you to take. Together, you and your doctor can decide what's best for you and your unique situation.
Visit the Breastcancer.org pages on Supplements in the Nutrition section for more information on supplements and suggestions on using supplements.
TORONTO, June 8 (MedPage Today) -- A majority of the women in a breast cancer study who were questioned during follow-up said they used antioxidants during treatment, researchers said.
The finding suggests that research is needed into how the use of antioxidants such as vitamin C and beta-carotene affects treatment outcomes, Heather Greenlee, N.D., Ph.D., of Columbia University Mailman School of Public Health in New York, and colleagues, reported online in Cancer.
"Given the common use of antioxidant supplements during breast cancer treatment, often at high doses and in conjunction with other complementary therapies, future research should address the effects of antioxidant supplementation on breast cancer outcomes," they argued.
Their Long Island Breast Cancer Study Project was a case-control endeavor to examine the role of environmental influences on breast cancer among women living in New York's Nassau and Suffolk counties.
Between Aug. 1, 1996 and July 31, 1997, 1,508 women with a first primary in situ or invasive breast cancer were enrolled in the study. Between 2002 and 2004, the researchers conducted follow-up interviews among case participants.
All told, 764 women completed a full interview and gave information on antioxidant use, Dr. Greenlee said.
The interviews asked about four antioxidants -- vitamin C, vitamin E, selenium, and beta-carotene -- as well as daily dose.
Intake of each supplement was categorized as none, low, or high, with high doses defined as more than 60 milligrams of vitamin C, more than 30 IU of vitamin E, more than 20 micrograms of selenium, and more than 5,000 IU of beta-carotene.
The researchers created a nine-point "antioxidant index" to summarize total intake, based on scoring the intake of each antioxidant as zero for never, one for low, and two for high.
The antioxidant index itself was divided into three categories -- none if the total score was zero, low if the score ranged from one through four, and high if it was five or higher.
Analysis found:
The researchers noted that the participants from the original study who agreed to take part in the follow-up were younger, more likely to be white, and of higher socioeconomic status than women who did not respond.
"We believe our results are generalizable to similar populations," they said, although study participants "may have been heavier users of antioxidants than breast cancer patients in the general population."
The study was also limited by a relatively low response rate of about 55.4% of the participants who agreed to be contacted again after the end of the original study, they said.
The study was supported by the Lance Armstrong Foundation, the National Cancer Institute, and the National Institutes of Environmental Health and Sciences. The researchers did not report any conflicts.
Primary source: Cancer Source reference: Greenlee H, et al "Prevalence and predictors of antioxidant supplement use during breast cancer treatment: The Long Island Breast Cancer Study Project " Cancer 2009; DOI: 10.1002/cncr.24378.
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