Are There Toxins in Your Breast Milk? Explaining with Science

Have you seen headlines like this one recently? ”Breastfeeding 'could be passing on toxic chemicals to babies.'” It's enough to make any nursing mom pause. 

What those articles rarely tell however, is the whole story about environmental pollutants and breastmilk. We'd like to set the record straight with the following facts.* And the bottom line? We live in a polluted world. The solution is not to stop nursing, but to stop polluting. So keep calm, and nurse on.

1) Levels of some chemicals in breastmilk have been going DOWN in recent years. Yes, there are chemicals present in breastmilk (and formula, see below). But research such as this study on fire retardants and this one on pesticides show that levels of key environmental pollutants have been going down in recent years as a result of policies limiting their use. Dr. Kathleen Arcaro, an environmental toxicologist at the University of Massachusetts who studies pollutants in breastmilk as well as breast cancer, explains that “the good news is that the concentration of some lipophilic (fat-loving) environmental pollutants in breast milk is decreasing. For instance, the level of many pesticides (DDT and its metabolites) and polychlorinated biphenyls (PCBs) has greatly decreased over the last 30 years.”

2) There are pollutants in formula, too, sometimes in higher amounts. You have to feed your baby something. So are your choices breastmilk which reflects our environmental exposures, or a perfect, chemical-free food? No.

Dr. Arcaro notes that “pollutants are widely distributed [i.e. in the air, in water, etc.] and therefore are in cow’s milk and formula.” Or put more colorfully by Dr. Jack Newman, “There are toxins in formula. Why would everything on earth be polluted, even the far reaches of the Arctic, but not formula?”

In the past, the FDA has found BPA (now banned from packaging) and trace amounts of melamine in some formulas, and another study found arsenic in an organic toddler formula. A CDC study of ten different types of formula found that “perchlorate was a contaminant of all commercially available [formulas] tested.” And one chemical, PAH, was found in the highest levels in formula and cow’s milk, and lowest levels in breastmilk.

We share this not to scare formula feeding moms but to emphasize to moms wondering if formula might be safer than breastfeeding that there is no pollutant-free choice. The choice is between two foods that reflect the polluted state of our environment. But one of those confers significantly more protection against numerous health problems

3)  Breastmilk may actually protect babies from some chemicals found in it. One study concluded that breastfed babies, due to healthy bacteria in breastmilk called bifidobacteria, may actually metabolize perchlorate. The study “found evidence that breast-fed babies can metabolize the environmental contaminant perchlorate, decreasing their risks of detrimental developmental effects from exposure.” 

4) Research has found no adverse consequences of some key chemicals found in breastmilk. While in utero exposure to chemicals has been found to be harmful, this Dutch study found no adverse developmental effects from exposure to dioxins (over twenty years ago, when exposure to dioxins were more common) through breastmilk. Other research “showed evidence that breast feeding counteracts the adverse developmental effects of PCBs and dioxins.” 

5) Not everything in the environment makes it into your milk. Our bodies have several systems for regulating what gets into our milk, and it’s worth understanding how they work. In order for a substance to get into breastmilk, it must pass through a number of “screens.” Some things we ingest are destroyed in our digestive system, eliminated from our bodies, or held in our livers before they even enter our bloodstream, which is where they may transfer into milk. And not everything that enters our bloodstream makes it into our milk, either. Only substances that are small enough in molecular weight to squeeze in between our milk-making cells, or fat-soluble enough to ‘hitchhike’ through the cell walls, make it into milk. Some substances do enter into our milk, but when the level in our bloodstream declines, substances can actually move out of the milk and back into our bloodstream. Even when something harmful does make it into your milk, your baby’s gut may destroy it or poop/pee it out before it can enter her bloodstream. Of course, these systems are not foolproof, and it’s important to emphasize that some harmful substances can enter milk that pose a threat to your baby. But these multiple systems may be why a substance like glyphosate can be present in mothers' urine but not be present in breastmilk. Much more on this topic can be found at the Infant Risk Center.

6)  Breastfeeding is still recommended. The CDC states: “Breastfeeding is still recommended despite the presence of chemical toxins. The toxicity of chemicals may be most dangerous during the prenatal period and the initiation of breastfeeding. However, for the vast majority of women the benefits of breastfeeding appear to far outweigh the risks. To date, effects on the nursing infant have been seen only where the mother herself was clinically ill from a toxic exposure.” 

7)  Concerned? Take action to protect your baby and the environment. We can take steps, both in our personal and public spheres, to make ourselves and our milk – and formula – more free of chemicals of concern. We can take a number of simple steps, as outlined by Healthy Child, Healthy World to reduce our exposure and to advocate for a safer environment. We can selectively shop for pesticide-free produce (without breaking the bank) using the Environmental Working Group's Dirty Dozen list (also available as an app), and use cleaner personal care products.

The solution is not to stop nursing, but to stop polluting. So finally, and most importantly, we can advocate for better regulation of chemicals in our environment, through many organizations working to make our world, and the lives of our children, healthier.

*The information in this post is provided for informational purposes only and not as medical advice. Some content in this post was originally published on the Best for Babes Foundation website.