Parabens are preservatives widely used in shampoos, cosmetics and other personal care products. These chemicals are weakly estrogenic, but whether that affects people who use products containing them remains to be seen. Concern about parabens underlies the persistent rumor that antiperspirants are a major cause of breast cancer. I can assure you that this is not true, but new evidence that traces of parabens have been found in breast cancer tissue has generated concern that they might play some role in the growth of breast cancer cells.
Here's what we know:
Results of a study published in the October 16, 2002 issue of the Journal of the National Cancer Institute found no connection between the use of antiperspirants and breast cancer. The study was a large one, including more than 1,600 women, about half of whom had breast cancer. When the use of antiperspirants, deodorants and shaving the underarm area with a blade razor were compared, no increased risk of breast cancer was found.
This year, results of a study published in the January/February 2004 issue of the Journal of Applied Toxicology revealed traces of parabens in breast cancer tissue. That finding doesn't mean that the parabens caused the breast cancer or even caused breast cancer cells to grow. The study did not reveal what other risk factors the women may have had. In fact, it raised more questions than it answered. The findings will have to be confirmed in larger studies before we can draw any conclusions about a possible role of parabens in breast cancer.
In the meantime, it is important to remember that other sources of estrogen present a much greater risk. These sources include the estrogen produced in a woman's body by her ovaries or by fat cells and from hormone replacement. In addition, xeno-estrogens in the environment as well as the hormones used to fatten up beef both can contribute to estrogen load much more readily than parabens. However, if products containing parabens or other chemicals make you nervous, shop in health food stores for personal care products that do not contain them.
Andrew Weil, M.D.