This finding concerned researchers since parabens have been shown to be able to mimic the action of the female hormone estrogen, which can drive the growth of human breast tumors.
However, this study showed no direct evidence that deodorants were linked to an increased risk of breast cancer. Further work is required to examine any association between estrogen and other chemicals found in deodorants and breast cancer, researchers say.
BBC News January 11, 2004
I have posted articles in the past warning of the dangers of antiperspirants, and now this study is raising concerns about deodorants as well. Antiperspirants and deodorants are not the same thing: Antiperspirants work by clogging, closing, or blocking the pores that release sweat--with the active ingredient being aluminum--so that they can’t release sweat. Deodorants work by neutralizing the smell of the sweat and by antiseptic action against bacteria, but do not prevent sweating.
The concern with antiperspirant is that the aluminum it contains is absorbed by the body and wreaks havoc in the brain, where it likely contributes to the growing numbers of people coming down with Alzheimer’s disease. So it appears that the urban legend that antiperspirants have been identified as the leading cause of breast cancer may actually have some truth to it.
A study was conducted in 2004 by Dr. Kris McGrath, a Chicago allergist who claims to have found a connection between antiperspirants, underarm shaving and cancer. He believes the culprits in these antiperspirants are the toxins in aluminum salts such as aluminum chlorohydrate. He says they don't normally penetrate the skin enough to cause a problem--unless the skin is shaven. If you disrupt the skin by shaving, it can open up the door, because just under the skin is the lymphatic system, which is connected to the breast.
In this study, more than 400 Chicago-area breast cancer survivors recalled their lifetime history of using antiperspirants and underarm shaving. He found that women who perform underarm shaving more aggressively had a diagnosis of breast cancer 22 years earlier than the non-users.
Now with the study above, British researchers have found traces of chemicals called parabens in tissue taken from women with breast cancer. These researchers also published a study last year in the Journal of Toxicology that suggested underarm cosmetics might be a cause of breast cancer. It is unclear how valid this proposed mechanism is, but it would sure seem safe to avoid all antiperspirants and deodorants just to be safe.
At the very least, if you are using a deodorant in order to avoid the aluminum in antiperspirant, you will also want to be certain that the deodorant you choose does not contain parabens.
Parabens are used as preservatives, and on the label they may be listed as methyl paraben, ethyl paraben, propyl paraben, butyl paraben, isobutyl paraben or E216. Look for natural deodorants, which should be available in your local health food store, but be sure to read the labels, as all "natural" deodorants are not paraben-free.
I personally have not used any antiperspirants or deodorants for over 20 years. Simple soap and water has served me quite well for the last two decades, and I don't ever recall anyone telling me I had an offensive odor. So, I suggest avoiding the chemicals, save some money, prolong your life and drop the underarm chemicals.