This abridged article was written by Tracy Cassels, PhD, and originally appeared on her blog, Evolutionary Parenting

As seems to always be the case, when a new article comes out suggesting breastfeeding “isn’t all that”, the media pounces on it. Tons of articles crop up reminding us that the “benefits” of breastfeeding either aren’t all that great or that we’re ignoring real risks about breastfeeding.  Well, another new article has done just that and grabbed headlines in most news outlets, proclaiming real risks associated with breastfeeding[1]. 

 

The Study That Spurred Media Driven Sentiments Urging Breastfeeding Should Be Limited:

The research looks at serum levels of perfluoritnated alkylates substances (PFASs) in children and compares rates of these chemicals based on breastfeeding exclusivity and duration.  The study, conducted almost 15 years ago, jointly by researchers at Harvard University’s Chen School of Public Health, the University of Copenhagen, the University of Southern Denmark, and the Faroese Hospital System, examined levels of these chemicals (which we don’t want in our system, discussion below) in a cohort of Faroese children at ages 11 months, 18 months, and 5 years and looked at how these levels were influenced by breastfeeding practices.  There were data for a total of 81 children. (Notably, the researchers included birth “serum levels”, but this was based solely on maternal values that were extrapolated to the infant. 

There is research on how these chemicals cross the placental barrier which was used to make the calculation herein, but this birth number remains controversial because it was not obtained directly from the infant and thus is not actually a serum level, but an estimate.)  The researchers found that the duration of exclusive breastfeeding increased the concentrations of several PFASs by 16-31% per month of exclusive breastfeeding.  Partial and no breastfeeding had very little effect on the serum levels of various PFASs.  The models controlled for previous serum levels, ingestion of whale meat (a prominent source of PFAS exposure exposure in the Faroe Islands), child sex, and the interaction between child sex and breastfeeding. This was done to try and ensure that the values found are related to breastfeeding per se and not another possible variable.

After weaning, children generally showed steady decreases in their levels of PFAS in accordance with half-life measurements found in previous research. Furthermore, the levels reached in these infants at 11 months (when most peaks were found, though it may have been higher during breastfeeding) were often higher than that of their mother. The transmission of these chemicals via breast milk suggested to at least one of the authors – Dr. Grandjean – that we should think twice about promoting breastfeeding for any duration after 3-4 months, and especially about promoting exclusive breastfeeding.  For the authors taken as a whole (i.e., what was written in the article), the concern is about the degree to which we are finding these chemicals in our environment and how these chemicals build-up in the human body over development. However, the media focus has been exclusively on the “risk” associated with breastfeeding.

 

What PFAS Are And Why We Should Care:

PFAS are chemicals used to make all sorts of industrial products and they enter our bloodstream due to our use of these chemicals and through our diet and drinking water.  Notably, the ingestion of these chemicals has been found in a wide array of foods, including meats, fish, and even microwave popcorn[2]. However, a review of the quantities in food products and the range of consumption (high versus low) suggest it is rare for people to exceed health-based guidance values[3], but there are exceptions to this. For example, a diet high in contaminated fish can result in higher toxicity levels or occupations where there is consistent exposure to these chemicals can result in toxicity[4]. Thus, women should be aware of their exposure levels both with respect to foods eaten and work performed.

When levels are high, it can have negative effects. One study found that vaccine uptake (specifically tetanus and diphtheria) was linked to PFAS exposure in that the vaccine antibody concentrations were found to be lower in those children with higher levels of serum-PFC (two specific long-chain perfluorinated alkylates which have been limited in use in recent years)[2].  Animal models have led to concerns about the health effects of these chemicals on humans, though epidemiological research is still scarce.  Many regions have put and are putting restrictions on the use of PFASs in manufacturing in order to limit their use and thus overall human exposure, especially in terms of the amount allowed in drinking water.  

 

But Wait – The Study Was Conducted 15 Years Ago:

For starters, more limits on the use of some of these PFASs have been enacted in the last 15 years, such as regulations on acceptable drinking water levels.  This regulation means that likely we are exposed to lower levels these chemicals than before.  Second, because the longer-chain PFASs were found to possibly be harmful thanks to animal research, replacements have been found by many of the major users of these chemicals[12][13].  For example, in 2005 the US Environmental Protection Agency declared that PFOA, one specific PFAS, was “likely to be carcinogenic in humans”[14] and we have since seen a drastic decline in the use of this specific PFAS in manufacturing.  These changes have meant that overall levels of some PFASs have actually decreased in the population of the years[12-13] and with this decrease, it is possible that the levels our infants are reaching are not of concern from a developmental or health perspective.

 

Despite The Study’s Claims, Breastfeeding Should Not Be Avoided Or Limited

There are a couple reasons for this.  First and foremost, the hypothesized concern in terms of PFAS exposure is based on research with respect to immune function and the uptake of certain vaccines[2].  However, as we know from myriad other studies, immune function is improved with extended breastfeeding.  In fact, as I’ve covered here  and here, the more research looks at breastfeeding in an evolutionary or biological manner, which includes exclusive breastfeeding for approximately six months to age 2 or longer, the greater risks to various health outcomes we see associated with formula use.

Second, the research makes a good case for breast milk being one of the most prominent ways in which infants obtain levels of PFASs in their system and the levels found were high, though we have no research proving any associated health problems in humans with the levels we are seeing (though there are studies that have found health problems in animal models[7], but as mentioned, epidemiological research has not found this to be the case in humans[6]). 

 

Why Choosing Formula Over Breastmilk Is Not The Answer:

Although formula does not contain high levels of PFASs, in most Western nations one of the primary sources of exposure to PFASs is through our drinking water (as opposed to the Faroe Islands)[6].  Well, guess what is used to mix with formula?  Thus, the question remains about how beneficial it would be to use formula mixed with PFA-contaminated water which the infant ingests directly instead of breast milk which at least also contains all sorts of immune-enhancing elements (see here), even for just these particular chemicals.  And of course, all of this ignores the myriad other ingredients found in formula that may be hazardous for infants or that may be influencing their immune reactions to various diseases (and why we see the effects of breastfeeding that we do). 

Thus, when we take a look at the totality of the evidence, there is no way that it even comes close to saying that the risks of breastfeeding with respect to these particular chemicals outweighs the risks of formula across myriad health outcomes and the presence of other chemicals.

Notably, in the research paper itself, none of the researchers actually suggest that breastfeeding should be limited; however, as mentioned, Dr. Grandjean has made comments to the press about this fact. As he was quoted stating in one article, “Breast feeding provides a net benefit during the first three or perhaps four months of exclusive breastfeeding. The benefits appear rather small after that.”  Yet the benefits in a Western context appear greatest with greater exposure to breast milk (in developing nations, the effects are so very great with any breast milk).  Oddly, when he discusses the safety of drinking water, he ignores research on how not all Western families have access to safe drinking water, but also that drinking water seems to be one of the primary sources of these PFASs for individuals in Western nations, even though this is mentioned in the introduction to this paper and by as covered by other research[6].

Most importantly, the researchers did not measure any level of immune functioning or health outcomes in the children of interest.  This means that the red flags raised about the increases in these PFAS levels are purely speculative and based on equally questionable research looking at antibody responses to two specific vaccines[2].  It is a case in which the findings seem to be oversold, especially when there are public declarations against breastfeeding, which also happens to counter tons of other scientifically backed research on the immune-benefits of breastfeeding.  Finally, this lack of evidence counters other research on how the immune-protective components of breast milk actually help counter any effect of a chemical or contaminant that may enter the infant’s system via breast milk.

 

The Takeaway:

All in all, the focus here really ought to be on the effects of these chemicals on our health and development with an emphasis on lowering our exposure to them full stop.  This means making companies more responsible for what is leaked into our environment and send into our homes, making mothers aware of how they are exposed to these chemicals so they can attempt to limit their own exposure and thus that of their infants, and more generally the effects of these chemicals on our ecosystem and environment which has great impact on our health.

Although we should not listen to someone suggest we ought not breastfeed because breast milk can transmit certain chemicals to our infants, we also shouldn’t ignore the very real effects that our environment has on our health and that of our families.  Being aware of what chemicals are found in your drinking water or the foods you eat are essential ways to knowing what both what you are ingesting and to what you may be passing on to your child.

 


About The Author: 

tracy cassels, evolutionary parentingTracy Cassels is the founder and primary writer for Evolutionary Parenting. She obtained her B.A. in Cognitive Science from the University of California, Berkeleym an M.A. in Clinical Psychology from the University of British Columbia, and her Ph.D. in Developmental Psychology, also at the University of British Columbia. Her academic works have been published in many peer-reviewed journals including Psychological Assessment, PLoS One, Personality and Individual Differences, Midwifery, and more. Tracy writes on the side with a group of researchers and gentle parenting advocates (including Dr. Darcia Narvaez, Dr. Kathleen Kendall-Tackett, Dr. Wendy Middlemiss, Sarah Ockwell-Smith, and Helen Stevens) who hope to expand awareness of the science and importance of attachment and evolutionary parenting. Most importantly to her, though, she is a mother to daughter Madeleine (Maddy, age 5), son Theodore (Theo, age baby), stepson Desmond, and wife to husband Brian. 

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References:

[1] Mogensen UB, Grandjean P, Nielsen F, Weihe P, Budtz-Jørgensen E.  Breastfeeding as an exposure pathway for perfluorinated alkylates.  Environ Sci Technol 2015; DOI: 10.1021/acs.est.5b02237.

[2] Grandjean P, Andersen EW, Budtz-Jorgensen E, Nielsen F, Molbak K, Weihe P, Heilmann C. Serum vaccine antibody concentrations in children exposed to perfluorinated compounds. JAMA 2012; 307:391–397.

[3] Post GB, Louis JB, Cooper KR, Boros-Russo BJ, Lippincott RL. Occurrence and potential significance of perfluorooctanoic acid (PFOA) detected in New Jersey public drinking water systems. Environ Sci Technol 2009; 43:4547–4554.

[4] Minnesota Department of Health. Health Risk Limits for Perfluorochemicals. In Report to the Minnesota Legislature. St. Paul, MN: Minnesota Department of Health; 2008.

[6] Steenland K, Fletcher T, Savitz DA.  Epidemiological evidence on the Arehealth effects of perfluorooctanoic acid (PFOA).  Environ Health Perspect 2010; 118: 1100-8.

[7] Seacat AM, Thomford PJ, Hansen KJ, Olsen GW, Case MT, Butenhoff JL. Subchronic toxicity studies on perfluorooctanesulfonate potassium salt in cynomolgus monkeys. Toxicol Sci 2002; 68:249–264.

[12] Calafat AM, Wong LY, Kuklenyik Z, Reidy JA, Needham LL. Polyfluoroalkyl chemicals in the U.S. population: data from the National Health and Nutrition Examination Survey (NHANES) 2003–2004 and comparisons with NHANES 1999–2000. Environ Health Perspect 2007;115:1596–1602.

[13] Olsen GW, Mair DC, Reagen WK. Preliminary evidence of a decline in perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) concentrations in American Red Cross blood donors. Chemosphere 2007; 68: 105–111

[14] U.S. EPA (Environmental Protection Agency) Draft Risk Assessment of the Potential Human Health Effects Associated with Exposure to Perflouroctanoic Acids and Its Salts. 2005