Human exposure to endocrine disruptors and breast milk

Endocrine system is one of the most sensitive communication networks of the human body which influences all aspects of human health and well-being, including reproductive potential, cognitive functions, thyroid and metabolism, digestion and hormonal balance. In recent years basic laboratory research has been focused on the potential relationship between environmental contaminants and cellular endocrine function. Environmental contaminants are ubiquitous in the environment, alter endocrine physiology and produce endocrine disruption without acting as classic toxicants. These endocrine disruptors (EDCs) are lipophilic and stored for long periods of time in the adipose tissue. Maternal exposure to EDCs during pregnancy and lactation has as a result the exposure of the fetus and neonate through placenta and breast milk. It has been recognized that human milk is the best natural food for neonates providing immunologic, developmental and practical advantages throughout childhood. However, contamination of human milk by the presence of environmental toxicants is widespread through the past decades due to inadequately controlled pollution. Persistent pesticides, chemical solvents and others tend to invade slowly the environment, to bioaccumulate in the food chain and to have long half-lives in animals and humans. During the past fifteen years, the scientific interest has been focused on xenoestrogens, i.e.,environmental chemicals with estrogen disrupting activity. Certain adverse health and reproductive outcomes are attributed to these chemicals in wildlife, in laboratory animals, as well as in humans. Although most toxic agents are hazardous in high doses, the human health risks associated with EDCs concern exposure to low doses. The human health risks that may be associated with these low-level but constant exposures are still largely unknown and highly controversial. In this paper, we review available data on environmental chemicals present in breast milk that may affect child health through breastfeeding. Specifically, we focused on the breast-feeding pharmacokinetic aspects related to infant exposure of chemical pollutants that have estrogen and antiandrogen activities, such as environmental estrogen disruptors or xenoestrogens.