Dioxins in Food Chain May Cause Poor Milk Production

B. Paige Lawrence, Ph.D.,
University of Rochester School of Medicine and Dentistry
NIEHS Grants R01ES013958, K02ES012409 and P30ES001247

An NIEHS-funded research team at the University of Rochester Medical Center reports that exposure to dioxins during pregnancy harms rapidly growing and dividing epithelial cells in breast tissue which may explain why some women have trouble breastfeeding or have poor milk production.

The studies were performed using laboratory mice and show that early administration of dioxin caused mammary cells to stop proliferating as early as six days into the pregnancy and lasted through mid-pregnancy. The researchers also determined that dioxin inhibited the induction of genes involved in milk-production and decreased the number of ductal branches and mature lobules in mammary tissue. The studies show that induction of the Ah receptor was crucial in producing the effect and that timing of the exposure was important.

Estimates suggest that three to six million mothers worldwide are unable to breastfeed or are unable to produce enough milk to nourish their babies. Breastfeeding has been shown over and over again to have positive benefits mother-child bonding and for the overall health of the child. Further research is necessary to find a link between dioxin exposure and problems with breastfeeding in women.

Citation: Lew BJ, Collins LL, O'Reilly MA, Lawrence BP. Activation of the pregnancy alters mammary epithelial cell proliferation and differentiation. Toxicol Sci. 2009 Jun 5.