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Every year, reports in news media describe environmental contamination events or the presence of lead, mercury, Persistent Organic Pollutants (POPs), or other things in our water, food, air, and ground. These media stories often raise concerns in nursing parents about the safety of their milk. Families’ fears of possibly doing their babies harm by nursing them may contribute to unnecessary early weaning (Geraghty, Khoury, Morrow, & Lanphear, 2008), particularly if they lack good support and information about the ways in which human milk and nursing outweigh and mitigate any risks due to contaminants (Hatcher, 1982). Early weaning itself can be harmful for both parent and baby.




Public health organizations around the world affirm the importance, safety, and value of human milk for the human baby. The World Health Organization (WHO), which conducts periodic reviews of the research published on contaminants and human milk, states definitively, “The benefits of breastfeeding far outweigh the toxicological disadvantages that are associated with certain POPs” (van den Berg et al., 2017, p. 94). Indeed, Nickerson states, “WHO recommends breastfeeding in all but extreme circumstances” (qtd. p. 31).   In its position statement supporting breastfeeding, the American Academy of Family Physicians (AAFP) concurs, explaining that certain components of human milk act to increase the infant’s elimination of some toxins and to protect the infant’s developing brain, central nervous system, and body as a whole (2018; see also Mead, 2008).


Likewise, the American Academy of Pediatrics (AAP) continues to promote breastfeeding as the optimal source of nutrition for infants by reaffirming its policy statement recommending “exclusive breastfeeding for about 6 months, followed by continued breastfeeding as complimentary foods are introduced” (2012; p. e827). The Centers for Disease Control and Prevention (CDC) consider breastfeeding “one of the most highly effective preventive measures” that can be taken to protect the health of babies (2017a). The National Health Service in the United Kingdom (UK) and the Australian Health Ministers’ Advisory Council are just two more of the many public health organizations around the world that promote human milk as safest for babies in nearly all conditions.


Many researchers also reiterate the importance and safety of human milk (e.g., Akhtar et al., 2017; Anadón, Martinez-Larrañaga, Ares, Castellano, & Martinez, 2017; Anatolitou, 2012; Clewell & Gearhart, 2002; Dimitriadou et al., 2016; Fromme et al., 2011; Fujii et al. 2012b; Geraghty, Khoury, Morrow, & Lanphear, 2008; Hatcher, 1982; Hernik et al., 2914; Landrigan, Sonawane, Mattison, McCally, & Garg, 2002; Ljung, Palm, Grandér, & Vahter, 2011; Lopes, Barreiro, & Cass, 2016; McFadden et al., 2016; Mead, 2008; Muehlendahl & Otto, 2013;  Nickerson, 2006; Pandelova, Lopez, Michalke, & Schramm, 2012; Picone & Paolillo, 2013; Pronczuk, Akre, Moy, & Vallenas, 2002; Renfrew et al., 2008; Solomon & Weiss, 2002; ‘t Mannetje et al., 2013; van den Berg et al., 2017). Muehlendahl and Otto explicitly state, “There are no toxicological reasons which could be taken as arguments against breastfeeding” (p. 17). Thus, health care organizations, health care practitioners, and researchers around the world confirm that human milk is the food best suited to meet a growing baby’s needs.




Researchers use human milk samples in order to learn how environmental pollutants are taken in by us, what levels are being seen, and how those levels are changing over time, because it is easier to obtain human milk samples than it is to obtain blood and fat samples, the other two primary human tissues used in such analyses (Abballe et al., 2008; Ma et al., 2012). In 1987, international research on several contaminants in human milk began, initiated by the WHO Regional Office for Europe. After the first round of studies, the WHO research group recommended repeating studies every five years to provide temporal trend analysis (Anadón, Martínez-Larrañaga, Ares, Castellano, & Martínez, 2017).


These time-based analyses have been important in their contribution to our understanding of environmental contaminants and their appearance in human milk. Decreases in the levels of most POPs have been demonstrated over the past two decades (Muehlendahl & Otto, 2013; Solomon & Weiss, 2002; ‘t Mannetje et al., 2013; Ulaszewska , Zuccato, & Davoli, 2011; van den Berg et al., 2017; Zhou et al. 2011), as 120 countries came to an agreement in 2001 to phase out or ban some of the worst POPs from being used for pesticides, flame retardants, and other commercial and industrial purposes (Anadón et al., p. 87). This treaty, known as the Stockholm Convention, established procedures for the safe use and gradual elimination of 12 POPs of significant concern, as well as for the addition of other chemicals to the list going forward. The downward trends offer clear reassurance to today’s nursing families.


Describing the safety of human milk even when contaminants have been detected, neonatal intensive care researcher Anatolitou (2012) states, “the detection of any environmental chemical in breast milk does not necessarily mean that there is a serious health risk for breastfed infants. No adverse effect has been clinically or epidemiologically demonstrated as being associated solely with consumption of human milk containing background levels of environmental chemicals” (p. 16). It is important to understand that many of the measurements of POPs in human milk are not clinically meaningful and, hence, are not a cause for alarm. Even more importantly, as mentioned earlier, a number of components of human milk act to counter potential risks of contaminant exposure (Anitolitou, p. 16).


The Centers for Disease Control and Prevention (CDC) point out that the only time effects of exposure have been detected in a breastfeeding infant have been cases when the mother was extremely ill (2010). In their review, Anadón et al. (2017) concur, explaining that only excessive exposure would be a contraindication to breastfeeding (p. 86; see also Hernik et al., 2014, p. 160). In addition, WHO has concluded that exposure to a developing fetus in utero is of greater importance than infant exposure through human milk (WHO/EURO, as cited in Pronczuk, Akre, Moy, & Vallenas, 2002, p. A350). Further complicating risk assessment for infants is lack of adequate comparative research.  Risk assessments of POPs for infants must balance the risks of contaminants in human milk against the risk already imposed by infants’ exposure in utero (Roosens et al. 2016), against the risk of exposure to contaminants in formula (Landrigan et al., 2002), and against the well-known benefits of human milk and nursing (e.g., AAFP, 2018; AAP, 2012; CDC, 2010, 2017a; LaKind et al., 2005; Lopes et al., 2016; Mead, 2008;WHO, 2017), yet very little research does so (Landrigan et al.; Nickerson, 2006; Renfrew et al., 2008; van den Berg et al., 2017).




Any accurate assessment of the risks of environmental contaminants in human milk requires comparison to contamination in artificial baby milks/formula (Renfrew, Hay, Shelton, Law, Wallis, Madden, et al., 2008). Very few contaminant studies make such comparisons, yet with families wondering whether weaning to feed their babies formula would be safer than nursing, the potential for contamination in formula is critical to consider.


Research confirms that risks of contamination of formula and water supplies used for making formula do exist. Contaminants in formula may include aflatoxins (carcinogens produced by certain molds, Akhtar, Shahzad, Yoo, Ismail, Hameed, Ismail, & Riaz, 2017), POPs, bacteria such as Cronobacter(CDC, 2017) and Salmonella (BBC News, 2018; WHO, 2018), insect parts, and other undesirable materials as well as potentially toxic amounts of essential trace elements and heavy metals (Akhtar, et al.; Lung, Palm, Grandér, & Vahter, 2011).


Clearly, there are risks associated with the production and possible deficiencies or excesses of formula (ScienceDirect), as well as the potential risks of early weaning. When parents switch their babies to formula in an attempt to avoid contaminants in human milk, not only may their babies still receive contaminated food, but also, the immunological benefits of human milk are taken from their babies.


We are now passing four decades of steadily increasing study of POPs in our environment, in our food, including formula, and in ourselves (Mead, 2008). McFadden, Mason, Baker, Begin, Dykes, Grummer-Strawn, et al. (2016) state: “Breastfeeding is nutritionally, immunologically, neurologically, endocrinologically, economically, and ecologically superior to breastmilk substitutes (BMS), and does not require quality control of manufacture, transport, storage, and feeding mechanisms” (p. 413).

Finally, remember the words of well-known researcher and breastfeeding advocate Miriam Labbok, MD, MPH, IBCLC:

“No environmental contaminant, except in situations of acute poisoning, has been found to cause more harm to infants than does lack of breastfeeding” (as qtd. in Mead, p. A434).


So, unless acute poisoning is the concern, continue to nurse your baby, secure in the knowledge that your milk is the only food that is uniquely created for your baby to meet their changing needs and that it offers immunological protections even against contamination.




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*Parts of the contents of this page was generously supplied by La Leche League International

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