There's no denying it: the chemicals that make up skin-care products give us females a boost in self-esteem and appearance-and make us smell nice. But over the years research studies have suggested that at certain exposure levels, some of these ingredients may contribute to cancer development in humans.
Because cosmetics contain a variety of chemicals, it's unlikely that one specific chemical will be identified as a definite cause of cancer. Still, many chemicals in skin-care products disrupt hormones. These disruptors block or mimic hormones such as estrogen, throwing off the body's hormonal balance. Because estrogen can make hormone-receptor-positive breast cancer grow, many women seek toiletries that limit their exposure to chemicals that act like estrogen.
While many ingredients go into cosmetics and personal-care products, two groups of chemicals are being studied for links to breast cancer:
- Parabens (for example, methylparaben, propylparaben, ethylparaben, and butylparaben) are chemicals commonly used to preserve cosmetic products, including makeup, moisturizers, hair-care products, personal lubricants, and shaving creams (most major brands of antiperspirants and deodorants don't contain parabens). Parabens are absorbed through the skin and exhibit weak estrogen-like properties. And some conditions that increase the body's exposure to estrogen (like not having children, late menopause, obesity, etc.) have been linked to an increased risk of breast cancer.
- Phthalates (for example, DEP, DEHP, DINP and DIDP) are chemicals commonly used to hold color and reduce brittleness in nail polish and hair spray. Fragrances in personal-care and cleaning products also contain them. As hormone disrupters, phthalates do not mimic estrogen, but they can disrupt the balance of other hormones that interact with estrogen, including testosterone.
The Controversy
In 2004 U.K. researchers found evidence of parabens in breast cancer tumor samples. This study added clout to an already popular belief that the parabens in underarm deodorants and sunscreen can move into breast tissue and fuel the growth of malignancies.
No direct evidence of a causal link between parabens and cancer, however, has been shown since then. A 2005 review of the data available at that time concluded that parabens would not increase the risk of any estrogen-mediated endpoint, including effects on breast cancer and that we are exposed to many phytoestrogens already in our diet that are naturally occurring endocrine-active chemicals.
The American Cancer Society agrees that there is insufficient scientific evidence to support a claim that use of cosmetics such as antiperspirants increases an individual's risk of developing breast cancer. Specifically, they note the following about the 2004 study:
- The researchers looked only for the presence of parabens in breast cancer samples. The study did not show that parabens caused breast cancer development in these cases - it only showed that they were there.
- Although parabens do have weak estrogen-like properties, the estrogens made in the body are hundreds to many thousands-fold stronger. So, natural estrogens (or those taken as hormone replacement) are much more likely to play a role in breast cancer development.
- Parabens are widely used as preservatives in shampoo, lotions, other cosmetics, and even foods. This study did not investigate the source of the parabens found in the breast tissue - it's not clear if they came from antiperspirants or some other source.
A review in 2008 mined various studies for answers to the following questions:
- Are there experimental or biological arguments supporting a potential link between the use of deodorants/antiperspirants and breast cancer?
- Does the use of deodorants/antiperspirants have any effect on the increase in the risk of breast cancer?
- Could a causal relationship between the use of deodorants/antiperspirants and breast cancer be accepted?
Their findings? "No scientific evidence to support the hypothesis was identified and no validated hypothesis appears likely to open the way to interesting avenues of research."
Many women's and environmental health advocacy groups disagree. As do many breast cancer survivors who blog about or otherwise address the subject. They take issue with conclusions that cosmetics harboring parabens and phthalates pose little or no hazard to the public. They note that while current studies do not causally link parabens with tumors, neither do these studies demonstrate that parabens are safe.
Women's Voices for the Earth, a women's environmental justice group from Montana, launched a campaign seeking the removal of toxic chemicals from beauty and skin products. As a result, the Campaign for Safe Cosmetics emerged as a coalition to pressure the cosmetics industry to phase out the use of chemicals known or suspected to be carcinogens. Specifically, this coalition has developed a voluntary agreement called the Compact for Safe Cosmetics. Companies that sign the compact agree to make all their products "free of chemicals that are known or strongly suspected of causing cancer, mutation, or birth defects." If a product is made from a chemical on a suspect list, the company will develop a plan to replace that chemical with a safer alternative within three years and publicly report its progress. The slogan of their campaign, "Because We're Worth It!" was meant to prick the conscience of those who disregard women's health concerns for the sake of profit.
Countering this movement, unsurprisingly, is the mainstream cosmetic industry. They argue that parabens, like most cosmetic ingredients, are safe based on their long-term use and safety record and recent scientific studies.
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