by Mary Jessica Hammes
November 16, 2008

It’s an impressive endorsement from scientists who work in environmental health: according to research published in the October issue of Environmental Health Perspectives, even when human milk contains pollutants, pesticides and heavy metals, it is still a better choice than formula.

We already know the numerous benefits of human milk, which are helpfully mentioned in the article: breastfeeding gives decreased risks of infection, allergies, asthma, arthritis, diabetes, obesity, cardiovascular disease and both childhood and adult cancers. Even the very first breastfeeding sessions are important—colostrum (the fluid secreted during the first days after birth) gives the baby immunologic protection, especially against the bacteria in the mother’s gastrointestinal tract and the bacteria near the mother’s anus (think about where the baby comes out in vaginal birth!).

But what about environmental toxins? Our bodies absorb all sorts of nasty stuff, such as persistent organic pollutants (known as POPs), which includes DDT—the first environmental pollutant found in breast milk in 1951, says the article. Our planet has not gotten less polluted since then, and now you can find all sorts of things in breast milk, like bisphenol A (hopefully you’ve read about it’s presence in many plastics here as well as in other news sources, like this recent article from the San Francisco Chronicle). Toxic metals, like lead, mercury, arsenic and cadmium have also been found in breast milk.

It’s pretty awful to think that your precious child is ingesting even trace amounts of that with your milk. But the good news is two-fold: one, you should still breastfeed, and two, you can make some simple changes in your lifestyle to help decrease the presence of those toxins.

Why still breastfeed?
The article mentions the October 2007 issue of Advances in Neonatal Care, a review by Joanne Jorissen, a certified nurse-midwife, in which she says that breastfed babies have greater cumulative exposure to cumulative PCB (polychlorinated biphenyls)—up to 18 percent higher, in fact. (Formula also contains heavy metals.)

Even so, “At this point, there is no evidence of a threshold among the general population beyond which the risks of breastfeeding outweigh the benefits,” Jorissen wrote in the review. “The majority of studies conclude that despite substantially higher PCB loads among breastfed infants, breastfeeding is still preferable to formula feeding.”

The article also contains a reassuring quote from Dr. Miriam Labbok, a physician-epidemiologist and director of the Carolina Breastfeeding Institute at the School of Public Health at the University of North Carolina, Chapel Hill.

“The fact that studies of child (health) outcomes in highly polluted areas are still better for the breastfed infant…would seem to indicate that certain factors in the production of human milk and in the milk itself, immunological and other, may mediate the potential harm of the ambient pollution,” says Labbok. “To date, no environmental contaminant, except in situations of acute poisoning, has been found to cause more harm to infants than does lack of breastfeeding.”

How to be healthier
How does the yucky stuff get in our milk in the first place? Take a look at your plate: up to 90 percent of exposure to persistent and lipid-soluble dioxin-like chemicals comes from your diet.

Higher concentrations of these chemicals are found in fatty foods like red meat, dairy and fish. (Vegetarians or mostly-vegetarians, take note: the article says that you generally have less POPs.)

In addition to getting more veggies on your plate, breastfeeding mothers can also get into shape: persistent lipophilic chemicals concentrate in your adipose tissue. In the latter part of your pregnancy, your lipids are mobilized for milk production—which means all of the chemicals are redistributed from tissue stores to the milk. A woman with a higher body mass index, says the article, will accumulate and therefore transfer more chemicals.

As for lead, it’s stored in the bones, and it’s more likely to stay put rather than transfer to the baby if you keep a good calcium intake and healthy bone metabolism during pregnancy.

The article is worth a read—not only for the compilation of facts that once again prove that breast milk is the best for your baby, but also because of a short history of evolutionary breastfeeding. Did you know, for example, that the majority of mothers in hunter-gatherer societies breastfed their babies beyond the age of 2, with the average weaning age around 30 months? And babywearing mothers who breastfeed on request, you can trace that instinct back to primate evolution and pre-industrial human history.

I can hear my ancient ancestors now, “I told you so.”