Human milk is healthiest, even with toxins

Many parents feel good about feeding their babies breast milk, and then frightened to hear that it contains not only vitamins and minerals but also chemicals. It’s true: Numerous bio-monitoring programs have found environmental contaminants in human bodily fluids, including milk, in recent years. But that’s only part of the story. Time and again, the bottom line from experts is this: Even when human milk contains such contaminants, it is still a better choice for babies than artificial 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 known 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 substance that contains environmental toxins still benefit babies’ bodies and brains? According to the U.S. Environmental Protection Agency (EPA), more than 80,000 common chemicals found in everyday products have not had to undergo testing prior to use. Human bodies are prone to absorb substances they come in contact with, such chemicals included. It’s not surprising, then, that all sorts of chemicals have found their way into all human bodily fluids, breast milk included. 

Studies of contaminants in human bodies didn’t look at breast milk initially. But, it’s easy to obtain and test, and the idea of chemicals in babies’ first source of nutrition captures the attention. It’s pretty awful to think of small, vulnerable babies ingesting even trace amounts of chemicals alongside the nutritional and disease-fighting components of human milk. Bisphenol A, perchlorate (from rocket fuel), flame retardant, weed killer, and toxic metals like lead, mercury, arsenic, and cadmium have all been found in breast milk. 

Fortunately, there’s good news, and it’s two-fold: You can—and should—still breastfeed. And 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 exist throughout the environment—even in infant formula. Giving your baby infant formula will not prevent them from exposure to these contaminants.

Bio-monitoring programs look for chemicals in breast milk because it is a 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, such reports can make breastfeeding seem unsafe and dampen mothers’ breastfeeding intentions. In one prospective study, more than 93 percent of surveyed mothers reported that they would discontinue breastfeeding and express and discard their milk if it was found to contain high levels of phthalates, while 78 percent said they would stop breastfeeding even if the levels were “low.” Concerns about chemicals might lead to early weaning from breastfeeding—even though the breast milk itself has other benefits or protections for the infant. 

Studies show that child health outcomes are still better for breastfed than formula-fed infants, even in highly polluted areas. As Director of the Carolina Breastfeeding Institute (University of North Carolina-Chapel Hill) physician-epidemiologist Dr. Miriam Labbok explains, “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 shown by study after study, demonstrating 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. “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. Those who eat less of these foods may 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. (Be sure to check the most recent list; EWG updates its shopping guide annually.) 
  • Exercise. In addition to getting more vegetables on your plate, pregnant women and breastfeeding mothers can 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, alternatives (such as infant formula) are produced in similarly chemical-heavy environments. 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 March 31, 2021

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