Human milk is healthiest, even with toxins

For many parents, it’s frightening to think that the breast milk their babies receive as nourishment carries not only vitamins and minerals but also a host of chemicals. It’s true, according to numerous biomonitoring programs that have been initiated in the U.S. in recent years. But it’s only part of the story. Time and again, the bottom line from experts is this: Even when human milk contains pollutants, pesticides, and heavy metals, it is still a better choice than infant formula.

The benefits of human milk are widely known: Breastfed children are at lower risk of infection, allergies, asthma, arthritis, diabetes, obesity, cardiovascular disease, and some childhood and adult cancers. (Another way to think of it—a perspective that has been gaining traction in recent years—is that formula-fed infants are at higher risk for these health conditions.)

Even the earliest “milk,” a golden-colored, sticky liquid commonly referred to as “colostrum” that a mother produces during the first 2–3 days of her baby’s life, conveys important immunological benefits. 

  • But how can any “natural” substance that includes environmental toxins still benefit our bodies and brains? The U.S. Environmental Protection Agency (EPA) has documented more than 80,000 chemicals in products we use everyday and in our environment, none of which had to undergo testing prior to use. Human bodies are prone to absorb substances they come in contact with, such as persistent organic pollutants (known as POPs), which includes DDT—the first environmental pollutant found in breast milk in 1951. Our planet has not gotten less polluted since then, and all sorts of chemicals have found their way into breast milk. It’s a fact that was largely ignored until the start of several biomonitoring initiatives and the widespread coverage of the topic by U.S. media for more than a decade. (For examples, see this article about bisphenol A from the San Francisco Chronicle, this piece about rocket fuel (perchlorate) from the LA Times, this article about flame retardant from The New York Times, or this post about weed killer from Consumer Affairs). Toxic metals, including lead, mercury, arsenic, and cadmium have also been found in breast milk. 

It’s pretty awful to think of small, vulnerable babies ingesting even trace amounts of chemicals alongside the infection- and disease-fighting components in human milk. But the good news is two-fold: 

  • You can—and should—breastfeed. 
  • You can make some simple changes in your lifestyle to help decrease the presence of toxins in your body and your family. 

Why breastfeed? 

The chemicals found in breast milk are found throughout the environment—even in infant formula. Biomonitoring programs analyze chemical presence in breast milk because it is a relatively convenient body fluid that can be obtained non-invasively, and because results give a sense of chemical load for both the mother and her breastfeeding infant.

Unfortunately, the process of conducting and reporting such studies can dampen mother’s breastfeeding intentions, as found by Sheela Geraghty and colleagues. In a prospective study, Geraghty surveyed 381 mothers from a larger birth cohort study about whether they would want to receive results of tests of their milk, and whether they would change their breastfeeding patterns based on the results. When asked if they would discontinue breastfeeding and express and discard their milk if it was found to contain high levels of phthalates, more than 93 percent of women surveyed said they would. Even if the levels were “low,” 78 percent stated that they would discontinue breastfeeding. Concerns about chemicals might lead to early weaning from breastfeeding—even though the breast milk itself might confer other benefits or protections to the infant. As physician-epidemiologist and director of the Carolina Breastfeeding Institute (University of North Carolina-Chapel Hill) Dr. Miriam Labbok explains, “[t]he 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. …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 a healthier breastfeeding mother 

Chemicals have been in our environment—and, unfortunately, our bodies and our breast milk—for decades, and yet the positive effects of breastfeeding over infant formula have been reinforced by study after study concluding that breast milk remains “best” for babies’ health.

Steps that can help reduce the chemical burden in your body and your breast milk include: 

  • Consider your diet. How do the chemicals get into breast milk in the first place? “You are what you eat” comes to bear: up to 90 percent of exposure to persistent and lipid-soluble dioxin-like chemicals comes from foods in your diet. Higher concentrations of these chemicals are found in fatty foods like red meat, dairy, and fish. Vegetarians or mostly-vegetarians may, therefore, have less POPs. The Environmental Working Group (EWG) encourages shoppers to further reduce their exposure to chemicals by avoiding the “dirty dozen” produce items consistently found to contain pesticide residue and buying “organic” options when available. (This list is reviewed every year so it is important to use the current year’s Shopping Guide.) 
  • Exercise. In addition to getting more vegetables on your plate, pregnant women and breastfeeding mothers can also get into shape. Many chemicals linger in fat cells, so a woman with a higher body mass index (BMI) will accumulate and transfer more chemicals. (The exception here is lead. It’s stored in the bones, and is more likely to stay put rather than transfer to the baby if you maintain a good calcium intake and healthy bone metabolism during pregnancy.) 

It’s important to remember that in spite of the presence of chemicals in our environment, breastfeeding is still best. In fact, all of the studies that have shown breastfeeding to confer important benefits for babies’ health and development have been conducted on chemical-laden milk; there simply isn’t any other kind. Moreover, any alternative (such as infant formula) would be produced in the same chemical-heavy environment. While there’s no way to escape exposure to chemicals, we can rest assured that a mother’s milk remains the healthiest source of nutrition for her baby.

Last updated May 30, 2017

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