Looking at 40 women undergoing mastectomies, the research team collected 160 breast tissue samples (four from each woman) and found that 99 percent of them contained at least one paraben. Sixty percent of the samples, meanwhile, contained all five of the most common parabens. Since about 1998, scientific studies have started raising concerns about the link between these chemical additives and the growing number of breast cancer cases. Previous studies suggested a link between the use of deodorant (which usually contains parabens) and the fact that a disproportionate number of tumours seem to develop in the upper-outer quadrant of the breast, closest to the underarm.
The new study, however, found that even women who did not use underarm deodorant still had parabens present in their breast tissue, suggesting that these chemicals are coming from more than just a single source. One of the lead researchers, Dr. Philippa Darbre of the University of Reading, notes that this study doesn’t confirm cause and effect: “The fact that parabens were detected in the majority of the breast tissue samples cannot be taken to imply that they actually caused breast cancer in the 40 women studied,” she said in a release. “However, the fact that parabens were present in so many of the breast tissue samples does justify further investigation.”