Multivitamins Linked to Breast Cancer Risk
Study Shows Higher Risk of Breast Cancer Among Women Who Report Taking Multivitamins
Possible Reasons for Breast Cancer Risk continued...
"There may be some components within a multivitamin that could potentially increase breast cancer risk, but the problem is we don't know which component," says Katherine Lee, MD, an assistant professor of medicine at Cleveland Clinic in Ohio.
In the new study, women did not provide information on what brands of vitamins they took; they simply reported whether or not they took them. There is a chance that recall bias may have affected their ability to accurately remember whether, or how often, they took multivitamins.
The new research did show that vitamin E, C, and B-6 did not appear to be responsible for the increased breast cancer risk. Calcium also appeared to provide protection from breast cancer, the new study shows.
"If you have a normal healthy diet, you probably don't need to take a multivitamin," says Lee. "Have a discussion with your physician about your diet and what food or food groups you avoid, and maybe consider adding supplements that address these deficiencies over a multivitamin," she suggests.
"I hope women don't toss all their multivitamins yet," she says. "We have to get at the heart of the matter."
Designing New Studies
More studies are needed to get to the bottom of the issue, says Gilbert Ross, MD, medical director for the American Council on Science and Health, a New York City-based consumer education group.
"If you really want to take multivitamins, this study is no reason to stop," Ross says. "Of course, on the other hand, I would advise anyone concerned that there is no good health or medical reason to take multivitamin supplements, except in rare cases of malnutrition."
"Focus on looking at food as the source of minerals and nutrients that we need in our lives," says Lorenzo Cohen, PhD, a professor and director of the Integrative Medicine Program at the University of Texas M.D. Anderson Cancer Center in Houston.
"We know that multivitamins and supplements are useful for people who are malnourished or deficient in particular minerals or vitamins, but more is not necessarily better," he says. "In a society where individuals have a vitamin and minerals at appropriate levels, supplementing with a multivitamin may not decrease your risk of cancer."