Study: Breast feeding still best despite environmental chemicals in human milk

University Park, Pa. -- The presence of environmental chemicals in human milk does not necessarily indicate health risks for infants, according to an international panel led by Cheston M. Berlin Jr., professor of pediatrics and professor of pharmacology, and Judy S. LaKind, adjunct associate professor of pediatrics at Penn State Children's Hospital. Few, if any, adverse effects have been documented as being associated with consumption of human milk containing background levels of environmental chemicals, and none have been clinically or epidemiologically demonstrated.

The Second Workshop on Human Milk Surveillance and Biomonitoring for Environmental Chemicals in the United States gathered a panel of experts representing academia, industry, nonprofit organizations and the federal government in September 2004 at Penn State Hershey Medical Center. The Journal of Toxicology and Environmental Health published workshop findings this month (September 2005, volume 68, number 20).

"We strongly emphasize that the mere presence of an environmental chemical in human milk does not indicate that a health risk exists for breast-fed infants," Berlin said. "All information gathered to date supports the positive health value of breast-feeding for infants."

The workshop explored issues related to the use of human milk biomonitoring for environmental chemicals including a wide range of chemicals to which women may be exposed -- industrial chemicals, chemicals in personal care and home/yard products, pharmaceuticals, and recreational and illicit drugs for understanding human exposure and health, and evaluating and communicating possible human health risk. Milk biomonitoring is a non-invasive method that provides information on levels of environmental chemicals in the body.

The 2004 expert panel noted "From a public health perspective, it is critical to consider the tools needed to conduct human milk biomonitoring without negatively impacting the already low breastfeeding rates."

"Breast-feeding is widely accepted internationally as the gold standard for infant feeding and has unparalleled advantages for both infants and mothers," said Berlin, chair of the workshop. "Advantages for infants include protection from infectious disease, optimal growth including neurodevelopment, and possible protection from certain diseases later in life. It is important to preserve breastfeeding as the best nutrition for infants."

Four areas were explored: human milk research designed to answer questions about health; exposure assessment issues; human health risk assessment; and methods for facilitating human milk research.

"Because human milk provides information on exposures of both the mother and infant, studies on associations with health outcomes for both the mother and infant are possible" LaKind, president of LaKind Associates LLC, said. "One of the points we've tried to make clear is that you cannot present risk-benefit information in a vacuum," she said. "That's why we also recommend looking at infant formulas and the chemicals in the water used to make the formulas. An example of this is the potential effects on infants from phytoestrogens -- plant compounds with estrogenic activity -- in soy-based formulas. In addition, the focus of most human milk biomonitoring studies has been on persistent, bioaccumulative compounds such as PCBs. Little work has been done on shorter-lived chemicals such as volatile chemicals or on chemicals in personal-care products."

This 2004 workshop was a follow-up of the first workshop (2002): an international panel that met at Penn State College of Medicine in Hershey. The 2004 panel identified a number of recommendations for future surveillance and research, including:

* Determining levels of environmental chemicals found in human milk and infant formula, including water used to prepare formulas and chemicals from synthetic nipples and bottles, with special attention given to those women who may have greater than background exposure;

* Identifying human biomarkers of exposure, susceptibility and effects to predict potential human health risks associated with specific environmental chemicals in human milk and infant formula;

* Developing methods to analyze the risks and benefits to infants and children exposed to environmental chemicals and endogenous chemicals via breast-feeding and/or formula-feeding;

* Evaluating the usefulness of human milk biomonitoring in identifying agents most likely to be associated with breast disease;

* Researching levels of environmental chemicals in human milk that may occur through occupational exposures;

* Creating an Internet-based database for recording levels of environmental chemicals reported in human milk and infant formula in a standardized manner, with interpretation.

The workshop was supported by the American Chemistry Council; the Centers for Disease Control and Prevention; the Department of Health and Human Services Health Resources and Service Administration; Health Canada; 3M Corp.; Penn State College of Medicine; Research Foundation for Health and Environmental Effects; and the U.S. Environmental Protection Agency Office of Children's Health.