Among breast cancer myths the concern that there may be a connection between deodorant use and breast cancer still persists. While a new study may finally let deodorants off the hook, one of its suspect ingredients may still be a cause for concern.
For many years, deodorants fell under suspicion for a few reasons:
- Most breast cancers are located in the outer, upper quadrant of the breast near the arm pit where deodorant is applied. The feeling was, “This couldn’t be a coincidence, right?”
- Parabens and aluminum, ingredients in some underarm products, were found in breast cancer tissue and both have weak estrogenic effects. And since estrogen is a risk factor for breast cancer, deodorants were suspect.
The latest study conducted by Dr. Philippa Darbe, who has been researching a possible connection between parabens and breast cancer for several years, found parabens in the breast tissue of women who had never used deodorants.
Darbe examined breast tissue samples from 40 women who had mastectomies and found widespread traces of parabens in breast tissue—even in the seven women who said they never used underarm products. Parabens were found in 158 of the 160 samples taken from the tissue collected from the 40 women. They found 96 samples contained all five of the most common paraben esters (forms).
The levels of paraben were four times higher than a similar study she conducted in 2004. This was a surprise as many manufacturers removed parabens from underarm products as a result of her 2004 study.
Darbe is quick to point out that her studies only reported the presence of parabens in breast tissue, not that parabens caused breast cancer. "I feel sure the issue is bigger than one chemical," she said. And, as many body lotions, sunscreens and cosmetics contain parabens, deodorants cannot be singled out. She believes that parabens in breast tissue come from a variety of sources.
Until more research is conducted to understand if parabens and other endocrine disruptors affect breast cancer risk, she suggests we cut back the use of cosmetic products as much as possible. "We simply use too much in the modern world -- too much for our body systems and too much for the wider environment," she said.
Other cancer experts echo Darby’s comments. The American Cancer Society finds no clear link between deodorant/antiperspirants and breast cancer. They note that, "There are no strong epidemiological studies in the medical literature that link breast cancer risk and antiperspirant use, and very little scientific evidence to support this claim." They add that Darby’s and other studies do establish that parabens found in topical skin products can be absorbed through the skin. The American Cancer Society maintains that more and larger studies are needed to find out what, if any, effect parabens might have on breast cancer risk.
Paraben Controversy Persists
The cosmetic industry continues to assert that parabens are safe and effective preservatives. They argue that:
- Parabens occur naturally in foods and are safely metabolized by the body and flushed out.
- They have very weak estrogenic activity compared to stronger estrogens in birth control pills, estrogen replacement therapy and natural phytoestrogens found in soy, red clover, and hops.
However, a recent study found that parabens act much differently when absorbed through the skin. When applied topically, parabens inhibit an enzyme called SULT that helps the body flush out estrogen. So, when SULT enzymes are deactivated, estrogen levels increase. These results suggest that chronic topical application of parabens may lead to prolonged estrogenic effects in skin as a result of reduced SULT activity.
As for whether parabens are metabolized when applied to the skin, another study found that after a month of applying methylparaben to skin cells, it "remained unmetabolized and persisted slightly" in the outermost layer of the skin. Additionally, it was found to affect DNA expression in the skin cells, inhibiting collagen production, and possibly leading to early aging of cells.
For more on other suspect ingredients in cosmetics, see The Real Cost of Beauty: Dangerous Toxins Lurking in Your Cosmetics.