Study Claims Dioxin Inhibits Mammary Gland Proliferation During Pregnancy
An animal study has reportedly claimed that dioxin “has a profound effect on breast tissue by causing mammary glands to stop their natural cycle of proliferation as early as six days into pregnancy, and lasting through mid-pregnancy.” Betina J. Lew, et al., “Activation of the aryl hydrocarbon receptor (AhR) during different critical windows in pregnancy alters mammary epithelial cell proliferation and differentiation,” Toxicological Sciences, June 5, 2009. Researchers with the University of Rochester Medical Center (URMC) apparently found that in mice, dioxin exposure “caused a 50 percent decrease in new epithelial cells,” in addition to altering “the induction of milk-producing genes” and decreasing “the number of ductal branches and mature lobules in the mammary tissue.”
These results built on earlier research led by corresponding author B. Paige Lawrence, who first discovered that when dioxin activates a transcription factor known as aryl hydrocarbon receptor (AhR), it impairs AhR’s ability to fight off infection. According to a June 9, 2009, URMC press release, dioxin is a ubiquitous incineration byproduct that humans ingest “most often through meat, dairy products, fish and shellfish,” after which point the chemical “settles in fatty tissues.”
“We showed definitively that a known and abundant pollutant has an adverse effect on the way mammary glands develop during pregnancy,” Lawrence was quoted as saying. “The best thing people who are concerned about this can do is think about what you eat and where your food comes from. We’re not suggesting that we all become vegans—but we hope this study raises awareness about how our food sources can increase the burden of pollutants in the body. Unfortunately, we have very little control over this, except perhaps through the legislative process.” See The Daily Green, June 10, 2009.
