Toxins in Formula or Cow's Milk vs. those in Human Milk:  A Comparison


This article is a relatively brief introduction to the subject of toxins in infant formula or cow's milk as compared with presence of toxins in human breast milk.  For much more detailed information on this topic, including about where those toxins come from in our environment, please go to


The Danish scientist who is author of nine studies on chemical contamination of human milk as well as over 40 other studies, as well as Head of the Section of Environmental Technology of the Danish Institute of Technology, made the following summary statement:  
"The average levels of persistent organohalogens in human milk are normally 10 to 20 times higher than the levels in cow's milk or infant formulas."(1)  Note that organohalogens include dioxins,
PCBs and PBDEs, all of which are substantially present in diesel emissions.(2)  Then note that diesel emissions were the environmental pollutants that were most strongly identified in the 2013 Harvard study that found close correlations between environmental pollution at the time and place of birth and rates of autism in the children braingrowthspurtJ.jpgborn.(3) 



Most growth and development of the infant brain takes place after birth (see chart), and the early-postnatal period is likely to be the period of greater vulnerability to effects of toxins. (see  Also note that the U.S. EPA observes that about 90% of the human body burden of dioxin comes from food consumed.



Aside from the general introductory statements above, there are many detailed studies that show major differences in toxic contents of human milk vs. formula or cow's milk.  See below.


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1)  A study in the Netherlands found that, at 42 months of age, the median plasma PCB levels of children who had been breastfed for at least 6 weeks were 4½ times as high as those of children who had been formula-fed. (ATSDR  (U.S. Agency for Toxic Substance and Disease Registry)  Public Health Statement for Polychlorinated Biphenyls (PCBs),  November 2000, Balfanz et al. 1993; MacLeod 1981; Wallace et al. 1996,  p. 569)

2)  According to an EPA report, providing estimates for typical exposure in the U.S. based on EPA data but also drawing on studies of populations in Germany (two studies), Britain and the Netherlands, "Breast-feeding for 6 months or more is predicted to result in an accumulated (dioxin) exposure 6 times higher than a formula-fed infant during the infant's first year of life.”  (Infant Exposure to Dioxin-like Compounds in Breast Milk,  Lorber and Phillips  Volume 110 | Number 6 | June 2002 • Environmental Health Perspectives   Also EPA Home/Research/Environmental Assessment: An Evaluation of Infant Exposure to Dioxin-Like Compounds in Breast Milk, Matthew Lorber (National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency) et al.

3)  A German study found that intake of dioxins was up to 50 times higher in breast-fed infants compared with formula-fed, and also that high proportions of the dioxins were intestinally absorbed by the breastfed infants.  At 11 months of age, the dioxin toxicity-equivalent concentrations in the formula-fed infants were about 10 times lower than in the infants that were breast-fed for six to seven months. (Intake, fecal excretion, and body burden of polychlorinated dibenzo-p-dioxins and dibenzofurans in breast-fed and formula-fed infants. Abraham K, Knoll A, Ende M, Päpke O, Helge H.  Children's Hospital, Virchow-Klinikum, Humboldt-Universität Berlin, Germany)  This study (Abraham et al.) was cited in a 2002 EPA document that apparently considered it to be fully valid. (Infant Exposure to Dioxin-like Compounds in Breast Milk  Lorber  and Phillips  Volume 110 | Number 6 | June 2002 • Environmental Health Perspectives

4)  PCB levels in children who had been breastfed for at least 12 weeks were still over twice as high as in bottle-fed children at 7 years of age, in an American/German study. (Pediatric Research (2001) 50, 331–336; doi:10.1203/00006450-200109000-00007  Early Childhood Determinants of Organochlorine Concentrations in School-Aged Children, Wilfried Karmaus et al.)

5)  In the only study quoted by the EPA comparing PBDEs in breastfed vs. bottle-fed children, based on measurements of 244 children (Carrizo et al., 2007), the average total concentration in children that had been breast fed was still nearly three times as high as average concentrations in formula-fed children at age 4 (3.6 ng/g lwt vs.1.3 ng/g lwt). (Section 5.6.2, second from last paragraph in that section, of U.S. EPA  (2010) An exposure assessment of polybrominated diphenyl ethers. National Center for Environmental Assessment, Washington, DC; EPA/600/R-08/086F   online at or

6)  In the only data regarding PBDE concentrations in infant formula that is provided in the EPA's PBDE Exposure Assessment (citing Schechter et al., 2006 a), two samples of infant formula were found to have PBDE concentrations of 32 and 25 pg/g wwt (wet weight), respectively. (Section 4.7, 2nd paragraph, of U.S. EPA  (2010) An exposure assessment of polybrominated diphenyl ethers. National Center for Environmental Assessment, Washington, DC; EPA/600/R-08/086F. online at or  Going by EPA data, total PBDE concentrations in mother's milk average about 1760 pg/g wwt or higher. (Section 5.6.2 of above, 2nd paragraph.)  The EPA states the figure as "44.1 ng/g lwt"  (44.1 ng = 44,100 pg).  For comparison purposes, the lipid (fat) weight indicated here needs to be converted to whole weight, which can be done as follows:  The EPA here assumes a fat content of 4%.  Using that figure, 44,100 pg/g lwt becomes 1760 pg/g wwt.) Such a difference in contents of this toxin between human milk and formula is not surprising, considering that about 90% of human intake of PBDEs comes from dust released by electronic devices within homes and buildings, according to the EPA; cows and soybean plants (the chief sources of alternatives to breast milk) obviously don't live inside houses containing TVs, computers and other electronics.

The reader is also encouraged to look at Section 1.g of for a large listing of hazardous chemicals found in breast milk, which are known to be ingested by mothers either by occupational exposure or from exposure to toxins in personal care and cleaning products, pesticides, dry cleaning chemical residue, household chemicals, paints, etc., or in either normal mood-altering medications or drugs of abuse, before being transmitted in breast milk.   It doesn't require much thought to realize that typical cows do not have significant exposures to occupational and household chemicals and mood-altering drugs, such as women have.


Additional evidence on the basis of which it is reasonable to surmise that toxins are much higher in human milk than in cows' milk or formula:

1) A Japanese study found high concentrations of five different kinds of PAHs in breast milk of rats that had been exposed to diesel exhaust for six hours a day from the seventh day of gestation until 14 days after birth, with concentrations similar to those in downtown Kanazawa, Japan. (Kanazawa is the study's lead author's university city, population 450,000).  PAH concentrations in the breast milk of the diesel-exposed rats were two to three times higher than in the control group, despite the fact that the exposure was apparently only moderately high. (Transfer of Polycyclic Aromatic Hydrocarbons to Fetuses and Breast Milk of Rats Exposed to Diesel Exhaust, Tozuka, Watanabe et al., Kanazawa University and Tokyo Metropolitan Public Health Research Institute; Journal of Health Science 50(5) 2004 pp. 497-502)  Although information about PAHs in cow's milk does not appear to be available for comparison, it is probably safe to assume that a much higher percentage of human females than of cows has a close exposure to diesel exhaust (from vehicular traffic, railroads, ships, port and canal dredging machinery, construction equipment, etc.), resulting in high concentrations of toxins from that exhaust in their milk.


2)  An Italian study found PAHs to be much higher in lactating women who smoke. The specific form of PAH that was investigated in this study was benzo(a)pyrene (BaP), which is classified as a Class 1 carcinogen by the International Agency for Research on Cancer. There is no determination of a maximum tolerable amount in breast milk, so the Acceptable Daily Intake (ADI) for drinking water was used in the study. "For babies whose mothers belonged to the non-smoker rural category, daily BaP equivalent intake during a six-month nursing period was below the ADI."  But intake of BaP in breast milk by infants of urban smokers showed values "from about seven times, up to 1000 times higher than ADI."  Breast milk of urban non-smokers was intermediate in concentrations. (Chemosphere. 2007 Apr;67(7):1265-74. Epub 2007 Jan 26.  Polycyclic aromatic hydrocarbons (PAHs) in human milk from Italian women: influence of cigarette smoking and residential area.  Zanieri L, et al., University of Florence, Department of Chemistry,  Florence, Italy. At )  Again, it is reasonable to assume that levels of atmospheric toxins in milk from most cows would be close to the levels in rural non-smoking women, many times lower than levels in milk from urban women.

3)  Mercury (another of the "persistent, bio-accumulative toxins" that increase greatly with each step up the food chain) would clearly accumulate more in humans who eat fish (that major dietary source of mercury), especially large fish, than would accumulate in cows or in soybean plants.  See Section 1.c of about the far higher levels of mercury in human milk than in cows’ milk or formula.


Comparison with another alternative source of infant exposure to toxins:

According to what is apparently the most thorough study on the subject of infant absorption of toxins from mother's milk vs. from fetal absorption, "Much higher doses of organochlorine compounds (from 10 to 20 times higher) penetrate the infant's body via the milk than via the transplacental route." (Concentration of Persistent Organochlorine Compounds in the Placenta and Milk of the Same Women, Katarzyna Czaja et al., Ch. 21 of Persistent, Bioaccumulative, and Toxic Chemicals I, Robert L. Lipnick et al. editors, ACS Symposium Series, American Chemical Society, 2001; citing Jensen, A.A. et al, Chemical Contaminants in Human Milk, CRC Press, Inc., Boca Raton, Ann Arbor, Boston, 1991.  Findings like the  above were confirmed in animal tests, with even greater contrasts.  (Ahlborg et al., Risk Assessment of Polychlorinated Biphenyls (PCBs), Nordic Council of Ministers, Copenhagen.  Report NORD 1992; 26 )  Note that PCBs and dioxins are included among organochlorine compounds.


Aside from the above reasons to believe that toxins are higher in human milk than in cows' milk or formula, we can probably also gain some insight from historical health data for the last four decades, as follows:  Average health outcomes have been worse for children born during periods of high breastfeeding than for children born in periods of low breastfeeding, in every case but one, when considering the disorders that the U.S. Surgeon General alleges to be "risks" of not breastfeeding full-term infants.  Not only highs but also lows and mid-levels of important diseases have correlated well with highs, lows, and mid-levels of breastfeeding rates, geographically, chronologically, and by demographic groups. (see


There is another result for which there is probably, somewhere, a cause

A highly-published scientist and Fellow of the American College of Nutrition (Raymond J. Shamberger) concluded, after a study of all 50 U.S. states and 51 U.S. counties, that "exclusive breast-feeding shows a direct epidemiological relationship to autism;" and also, "the longer the duration of exclusive breast-feeding, the greater the correlation with autism."(4)  It is conceivable that these correlations are related to the undisputed presence of high levels of toxins in human milk.  For more information about correlations between autism prevalence and exposure to toxins in human milk, see


For more information about effects on infants of the specific toxins discussed above, and where those toxins come from in our environment, please go to

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Perfluorinated compounds are sometimes referred to in comparisons of toxins in breast milk and formula.  A relevant study found the following:

“In this study, breast milk collected from seven countries in Asia was analyzed (n=184) for nine PFCs, including perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA). In addition, five brands of infant formula (n=21) and 11 brands of dairy milk (n=12).  the lowest concentration of 39.4 pg/mL was found in India, and the highest concentration of 196 pg/mL was found in Japan. The measured concentrations were similar to or less than the concentrations previously reported from Sweden, the United States, and Germany (median, 106-166 pg/mL). PFHxS was found in more than 70% of the samples analyzed from Japan, Malaysia, Philippines, and Vietnam, at mean concentrations ranging from 6.45 (Malaysia) to 15.8 (Philippines) pg/mL PFOA was found frequently only in samples from Japan; the mean concentration for that country was 77.7 pg/mL. None of the PFCs were detected in the infant-formula or dairy-milk samples from the U.S. except a few samples that contained concentrations close to the limit of detection.  (Tao L, et al.,(Wadsworth Center, New York State Department of Health, Albany, USA), Perfluorinated compounds in human breast milk from several Asian countries, and in infant formula and dairy milk from the United States. Environ Sci Technol.  2008 Nov 15;42(22):8597-602. at


Breast-milk-versus-formula contents of perchlorate, lead, and numerous other toxins:  See .


For a much more complete discussion of the significance of these toxic exposures regarding development of infants, see





(1) Jensen, A.A. et al, Chemical Contaminants in Human Milk, CRC Press, Inc., Boca Raton, Ann Arbor, Boston, 1991, p. 287. (Most local libraries would not have this, but it should be available as an Inter-Library Loan.)

(2) (Dioxins and PCBs are well-known components of diesel emissions, and PBDEs are also present in those emissions):  Aerosol and Air Quality Research, 11: 709–715, 2011  Copyright © Taiwan Association for Aerosol Research  ISSN: 1680-8584 print / 2071-1409 online doi: 10.4209/aaqr.2011.05.0058  Reduction of Toxic Pollutants Emitted from Heavy-duty Diesel Vehicles by Deploying Diesel Particulate Filters  Lien-Te Hsieh et al. at


(3)  Perinatal Air Pollutant Exposures and Autism Spectrum Disorder in the Children of Nurses’ Health Study II Participants, Roberts et al., published June, 2013 in Environmental Health Perspectives, at .


(4) Autism rates associated with nutrition and the WIC program.  Shamberger R.J., Phd, FACN, King James Medical Laboratory, Cleveland, OH  J Am Coll Nutr. 2011 Oct;30(5):348-53.  Abstract at  The full text, including the quoted passages, can be purchased for $7 or reference librarians at local libraries could probably obtain it at no charge. 




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