Apparent Effects of Breastfeeding

(Letters containing basically the contents below were sent twice to Surgeon General Benjamin and to responsible officials of the U.S. Department of Health and Human Services and the three doctors' associations that deal with this topic (pediatricians, family physicians, and obstetricians & gynecologists).  As of 2 and 8 months later, not one reply received has said anything to criticize any of the points below.)



The presumed benefits to infants of breastfeeding have been determined on the basis of observational studies, which can find "associations," from which only "inferences" can be drawn. This is acknowledged by Surgeon General Regina Benjamin, in her "Call to Action to Support Breastfeeding 2011" (p. 33).1  Observational studies conducted in Florida would find that sunshine is "associated" with a high death rate, and people could overlook the unusually advanced ages of many Floridians when finding this correlation of death rates with sunshine.  In a similar way, many people overlook the (confounding) fact that bottle-feeding mothers are unusually likely to be of low income1and to smoke.2  Conditions related to low income and smoking are known to lead to all of the adverse health outcomes that many people attribute to bottle feeding.3. 


The American Academy of Family Physicians points out that most Americans born in the middle of the 20th Century were not breastfed; but by the end of the 1970's, breastfeeding had become the norm.  So by now we have four decades of data that allow us to compare the health averages of the low-breastfed generation with those of the highly-breastfed young people who followed.  As it turns out, not a single one of the disease reductions that would have been predicted on the basis of the claims about breastfeeding has materialized.  In fact, outcomes have turned out to be significantly worse in all but one of the disorders that would have been expected to improve based on those claims, as found in an item-by-item examination of the claims and data.4


One of the disorders alleged to be reduced by breastfeeding:  See what actually happened.


Leukemia is alleged to be reduced by breastfeeding, but it actually increased by 30% between 1975 and 1995, while (a) breastfeeding rates also increased greatly, and (b) while leukemia was not increasing among adults. When breastfeeding rates were flat, childhood leukemia incidence was also flat.4 relationship between breastfeeding and childhood cancer in general is also of interest.  The Western U.S. is the region lowest in known carcinogens, and therefore is the best region for seeing effects of a single source of those toxins. There, higher and lower breastfeeding percentages in 2001-2003 were very good at predicting childhood cancer rates in 2005-2009 -- see chart on left. The relationship is similar for the rest of the U.S. states – see


Researchers from the Norwegian University of Science and Technology summarized "the largest study that has been done on breast-feeding and health," which was apparently also the only breastfeeding study that has utilized randomization, the best way to avoid effects of confounders. Their statement was as follows:  "This study cuts the legs out from underneath most of the assertions that breastfeeding has health benefits." 6

Looking at this chart, be aware that (after many low years) U.S. 6-month breastfeeding rates quadrupled in 11 years after 1971.1  Notice that, for each individual age group shown, obesity levels did not increase significantly until the very first period in which part of that specific group's infancies came after 1971.

Obesity also increased among older Americans during these years, but it increased 2.4 times as much among the more-breastfed 6-11 age group as among the 35-74 age group.  And the older group had a clearly understandable reason for its increasing obesity, which was the great decline in physically-active jobs in agriculture and manufacturing during the last half century.5

Relevant to the above, it is not well known that four studies have found strong associations between higher rates of breastfeeding and higher rates of childhood obesity, including the largest such study ever done and the only one to randomize. Those are part of a total of at least 52 scientific studies that found adverse effects of breastfeeding related to ADHD, autism, asthma, allergies, diabetes, and developmental problems and no effect with regard to SIDS.5a  (SIDS is one of the risks that is often alleged to be decreased by breastfeeding.)


Average exposures to dioxins, which are carcinogens and developmental toxins, are over 300 times higher in breastfed infants than the EPA's estimated safe dose at initiation of breastfeeding, gradually tapering off to 24 times higher after a year.7  Dioxin toxic equivalency in typical contemporary U.S. breast milk is scores to hundreds of times higher than the dosage in infant formula.8 



Dioxins and PBDEs are known to reduce testosterone; since testosterone is important to brain development and especially important to males, increased exposure to dioxins and PBDEs (in contemporary breast milk in developed areas) helps explain why autism and ADHD are especially prevalent in males. 

Ingestion of these known developmental toxins by infants by means of breastfeeding – during the normal period of breastfeeding -- is especially significant in that a very large part the growth and development of the brain, including about 85% of the growth of the cerebellum, takes place in the first year after birth.8b  In that regard, note that 2013 study in the NIH’s National Library of Medicine generalized, based on many earlier studies, that “the cerebellum has emerged as a region of interest in autism studies because of converging findings from human postmortem research, human neuroimaging studies, and animal models….”  Notice how well the cerebellum’s period of greatest vulnerability to toxins coincides with the period of very frequent, regular ingestion by infants of a food that is known to be extremely high in developmental toxins.


European countries with the highest breastfeeding rates (mainly Nordic) have the highest autism rates and the highest childhood cancer rates, and the lowest-breastfeeding European countries (U.K., Ireland, France and Belgium) have the lowest rates of both diseases, with only one minor overlap between the two groups.9  Autism rates appear to be less than half as high in the low-breastfeeding countries as in the highest-breastfeeding countries.9a

In a major U.K. study, 65% of children with autism had received major breastfeeding,9b compared with only 28% of children in the general population.10   A smaller U.S. study found similar results, but with an even more pronounced ratio.11  A 2011 study of all 50 U.S. states and 51 U.S. counties, carried out by a highly-published scientist who is also a Fellow of the American College of Nutrition, found that "the longer the duration of exclusive breast-feeding, the greater the correlation with autism."12


Children of WIC (assistance) recipients have autism rates 40% as high as children of college graduates.12a  Relevant to that, U.S. high-school-graduate mothers breastfeed at half as high a rate as college-graduate mothers.1  Blacks breastfeed at a rate about half as high as whites, and their rates of autism and certain childhood cancers are about 50% lower than among whites.13  Hispanics are in between in all respects.


Breastfeeding mothers reduce their own body burdens of toxins, "decontaminating" themselves, by transferring toxins to their babies in breast milk.14  This transmission of toxins takes place during a very rapid period of development of the infant brain, and it preceeds a period of especially high incidence of childhood cancer.     


A fourth child’s risk of autism is half as high as that of a firstborn, on average, and the odds of being diagnosed with autism continuously decrease from first to later children.15  Toxins from breast milk decline greatly with succeeding births:  Infants later in birth order are less likely to be breastfed, they are likely to be breastfed for shorter periods, and the milk they receive has toxin levels that have been reduced as a result of excretion to earlier-born infants during previous breastfeeding.16 Remember that, between 1971 and 2010, breastfeeding rates increased greatly in the U.S. There are no surveys that show consistent child health data for that entire period, but there are separate studies for major segments of that period, which regularly show unfavorable trends among children (such as shown in this chart). These adverse trends occurred despite huge declines during those years in child blood levels of the developmental toxin, lead,17 and despite major other pollution reductions. 



Bearing 1971 in mind as the starting year of the dramatic increase in breastfeeding, note that ADHD went from being minor, not even named until 1980, to prevalence of 11.4% among the 10-17 age group in 2010.17a  In a 2004 study, it was pointed out that it was being increasingly recognized that attention deficit hyperactivity disorder persists into adulthood."18  So it appears that it was only after infants of the 1970's became adults that major signs of real long-term seriousness of ADHD became apparent.  


Related to the above, PBDEs have been increasing especially rapidly in the environment, and typical human milk appears to be over 50 times as high in PBDEs as formula.19  One study found that children who had consumed breast milk containing PBDEs at levels in the two upper quartiles were 2˝ and 3.3 times as likely (as children below median) to have behavior test scores indicating likelihood of developing into ADHD.20   So, in close association with increased levels of known toxins in the human milk they consumed, nearly half of the breastfed children in the study group had greatly increased likelihoods of having ADHD.



Diabetes: There was only one world region (Central/Eastern Europe) in which the 1995-2010 increase in breastfeeding rates was very exceptional, rising over 200%. (The second highest increase was less than 100%.)21  In a study of over 29,000 cases of childhood type 1 diabetes in Europe over the period 1989-2003, "rapid rise” of type 1 diabetes in children age 0-4 in this same Central/Eastern Europe region was seen as "especially striking."21a

Looking at the opposite extreme:  Information about childhood diabetes provided by the Diabetes Mondiale Project Group, for 1990-1999, includes the following:  "Trends estimated for continents showed statistically significant increases all over the world..., except in Central America and the West Indies where the trend was a decrease of 3.6%."22  The researchers did not try to explain why this region was exceptional.  However, it is noteworthy that this region was apparently the only world region in which breastfeeding rates declined in recent decades.23


Asthma and allergies:  These are alleged to be reduced by breastfeeding.  However, 22 easily-found studies in medical journals (mainly the most recent studies) determined that these diseases actually increased in children who were breastfed, with several of the studies finding higher disease rates to correlate with longer durations of breastfeeding. 

Childhood diabetes:  Six studies found that childhood diabetes increased with increased breastfeeding.23a


SIDS:  The commonly-cited review of breastfeeding-related studies failed to mention that a clear majority of the high-quality studies about SIDS and breastfeeding found no favorable effects of breastfeeding. The historical record supports that lack of relationship.  (See Section 9 of; that site also shows that almost all of the other diseases alleged to decrease with breastfeeding instead actually increased )

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Immune cells in breast milk are often considered beneficial, but that may be untrue over the long term in the current hygienic conditions in developed countries, which already have low microbial exposure compared with what our species became adapted to.  Quoting from the UCLA Food & Drug Allergy Center, "Overwhelming evidence from various studies suggests that the hygiene hypothesis explains most of the allergy epidemic;"24 in other words, the recent reductions in microbial exposures of infants probably result in later harm.  Bear in mind that long-term immunity (such as is created by vaccinations) is created by challenges that stimulate development of the immune system.  Consider where short-lived immune cells from outside the body, destroying microbes, fit into the picture of microbial challenges needed to stimulate development of the immune system.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Gestational vs lactational exposure:  Many people make the assumption that the greatest exposure of a baby to maternal toxins would occur during pregnancy, but that is apparently not the case.  According to what is probably the most thorough study on this subject of infant absorption of toxins from mother's milk vs. from fetal absorption, "Significantly more (10 to 20 times) of a mother's body burden of persistent organohalogens is transferred to the infant via the milk than by the transplacental route."26 (Note that dioxins, PCBs and PBDEs, part of the diesel emissions that are especially implicated with autism, are included among organohalogens.)  Also, in just the first 15 days of lactation, the amount of mercury transferred to an infant has been found to equal a third of the total that is transferred during gestation,27 and it obviously continues on from there, depending on the duration of breastfeeding.  Moreover, substantial development of the brain continues after birth, and many studies have shown postnatal exposures to be linked to neurological harm whereas prenatal exposures to those same chemicals are not. (see Section 3.a.1 of

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Note that currently there are basically unexplained epidemics in childhood obesity, asthma, allergies and diabetes; and developmental disabilities (including autism and ADHD) have increased greatly; such high levels apparently were unknown in the 1960's, when breastfeeding rates were low.25 Notice (above) that the increase of childhood diabetes was "striking" only where breastfeeding increased very sharply, and it declined only where breastfeeding declined.  From pages 1 & 2, remember the many correlations of high and low rates of autism, cancer and obesity with highs and lows of breastfeeding. Also bear in mind that U.S. breastfeeding rates increased several-fold between 1972 and the present;1 if that feeding had been genuinely beneficial, there would have been declines in children's disabilities. Instead, there have been substantial increases. That relates to our contemporary conditions of historically low microbial exposure and high content of developmental toxins in human milk.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A logical question that comes up, then, is Should parents be unreservedly advised by medical authorities to breastfeed their infants, while they are uninformed about the above important points?  If you believe that parents have a right to make such decisions based on complete information, please let us know that you are willing to sign on, by e-mailing to

Further relevant information, with links to sources, can be found at

The web address of this article is 




- (1) -- "Surgeon General's Call to Action to Support Breastfeeding 2011", p. 33, Table 2 and Figure 1 at

(2) - Breastfeeding Initiation and Duration: A 1990-2000 Literature Review Cindy-Lee Dennis, RN, PhD JOGNN in Review, Vol. 31, No. 1 (abstract at; also Gallup Well-Being, 3/21/08 Among Americans, Smoking Decreases as Income Increases by Rob Goszkowski

- (3) Child Health Care and Social Factors: Poverty, Class, Race by B. Starfield, MD, MPH, Head, Div. of Health Policy, Johns Hopkins Univ., and many other sources listed in footnotes 9 and 10 at

- (4) For details and sources, see , Sec. 10.a; also Table 20.2, Age-Adjusted SEER Cancer Incidence Rates, at

- (5) For more information about obesity increases in the older groups, and for information about chemicals in breast milk that probably underlie increases in obesity following increases in breastfeeding, see

- (5a) See

- (6) "Breastfeeding is not as beneficial as once thought" (06.01.2010) on a web page of the Norwegian University of Science and Technology, at . Their statement was based on findings of the PROBIT study in Belarus.

- (7) Infant Exposure to Dioxin-like Compounds in Breast Milk  Lorber (EPA senior scientist) et al., Vol.110, No. 6, 6/02, Environmental Health Perspectives #Download, and EPA document at regarding safe dose.

- (8) Breast milk dioxin data from (7) above, relating to data about infant formula from: U.K. Food Standards Agency,  Dioxins and Dioxin-Like PCBs in Infant Formulae, 49/04 March 2004, found at

- (8a) Perinatal Air Pollutant Exposures and Autism Spectrum Disorder in the Children of Nurses’ Health Study II Participants, Andrea L. Roberts et al.,  found at

- (8b) Dobbing et al., in brain growth study provided by NIH at

- (9) Breastfeeding rates from WHO, European HFA Database; autism data from many sources, cited in, third link, Sections 1.2.s.4-5; cancer rates from "International Comparisons of World Age-standardised Incidence Rates for Childhood Cancer: 1998-2000," Figure 4, from a website of Queens Univ., Belfast, Ireland, at,176738,en.pdf ; also other sources.

- (9a) for country-by-country data, see Section 1.2.p of .

- (9b) "Trends in Developmental, Behavioral and Somatic Factors by Diagnostic Sub-group in Pervasive Developmental Disorders" pp. 10, 14 P. Whiteley (Univ. of Sunderland, UK), et al., Autism Insights 2009:1 3-17 at

- (10) Multiple sources, shown in the Appendix , below.

- (11) Presentation by P.G. Williams, MD and L.L. Sears, MD, at INSAR conference in Kentucky, found at

- (12) 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

- (12a) CDC data at


 For ease of referral to the sources indicated here, if there is no highlighted link, you can (a) use your cursor to drag over and select a URL from the footnote (select the letters beginning with www or http and ending just before the next space; be sure to select all of that but no more, not even a space), then (b) control - c  (to copy that); then (c) paste that (control - v) into the horizontal web-address slot at the top left of your browser page, then press ENTER on your keyboard. 


- (13); also American Journal of Public Health. 2003 December; 93(12) "Low Breastfeeding Rates and Public Health in the United States" J. H. Wolf, PhD, re breastfeeding rates among blacks; for childhood cancer rates among blacks, childhood/ infant.pdf; for autism rates, 2007 National Survey of Children's Health, Child Trends DataBank

- (14) Decrease in milk and blood dioxin levels over two years in a mother nursing twins: estimates of decreased maternal and increased infant dioxin body burden from nursing. Schecter A et al, Department of Preventive Medicine, State University of New York, Health Science Center -- Syracuse, USA Chemosphere. 1996 Feb;32(3):543-9.

- (15) American J.of Epidemiology, Dec. 2008; 168(11): 1268–1276. 2008 October 21. doi: 10.1093/aje/kwn250 "Advanced Parental Age and the Risk of Autism Spectrum Disorder" Maureen S. Durkin et al.

- (16) U.K. source at; also "Factors Influencing Full Breastfeeding ..." Tammy J. Clifford, PhD, Human Lactation, 2012; also see footnote 11.

- (17) In 1976-1980, 88.2 percent of children 1 to 5 years of age had blood lead levels that were more than 10 micrograms of lead per deciliter. By 2003 that had declined to 1.6 percent. CDC, National Center for Environmental Health. Lead research, as quoted by Trends Data Bank. Accessed July 21, 2005

- (17a) See Section 2 of

- (18) The Future of Disability in America. Ch. 3 Institute of Medicine Committee on Disability in America; Field et al, ed National Acad.. Press (US); 2007 bookshelf ID: NBK11437

- (19) 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

- (19a) Diagnostic controversies in adult attention deficit hyperactivity disorder. McGough JJ, et al., Am J Psychiatry. 2004 Nov;161(11):1948-56.

- (20) Lactational Exposure to Polybrominated Diphenyl Ethers and Its Relation to Social and Emotional Dev't among Toddlers Hoffman, et al., Environ Health Perspect. 10/2012;


 For ease of referral to the sources indicated here, if there is no highlighted link, you can (a) use your cursor to drag over and select a URL from the footnote (select the letters beginning with www or http and ending just before the next space; be sure to select all of that but no more, not even a space), then (b) control - c  (to copy that); then (c) paste that (control - v) into the horizontal web-address slot at the top left of your browser page, then press ENTER on your keyboard. 


- (21) Developing World data from Other data from WHO/HFA datab.

- (21a) Incidence trends for childhood type 1 diabetes in Europe 1989-2003 and predicted new cases 2005-20: a multicentre prospective registration study CF Patterson et al.,, Vol 373, June 13, 2009

- (22) Incidence and trends of childhood Type 1 diabetes worldwide 1990-1999. DIAMOND Project Group. Diabet Med. 2006 Aug;23(8):857-66.

- (23) Various sources, mostly from UN, cited in endnotes 8w and 8wa at

- (23a) 19 studies summarized and cited in endnotes at and 7 studies cited in Section 3 of

- (24)  "About Allergies/ Why Are Allergies Increasing?"

- (25) For extensive data and discussion on this subject, see

- (26) Jensen, A.A. et al, Chemical Contaminants in Human Milk, CRC Press, Inc., 1991, p 15. Ahlborg et al., Risk Assessment of Polychlorinated Biphenyls (PCBs), Nordic Council of Ministers, Copenhagen. Report NORD 1992; 26

- (27) Exploration of Perinatal Pharmacokinetic Issues  Contract No. 68-C-99-238, Task Order No. 13  Prepared for Office of Research and Development,  EPA, by: Versar, Inc. EPA/630/R-01/004, Section,  at 

 For ease of referral to the sources indicated here, if there is no highlighted link, you can (a) use your cursor to drag over and select a URL from the footnote (select the letters beginning with www or http and ending just before the next space; be sure to select all of that but no more, not even a space), then (b) control - c  (to copy that); then (c) paste that (control - v) into the horizontal web-address slot at the top left of your browser page, then press ENTER on your keyboard. 





More on the Strong Association between Breastfeeding Rate and Diagnosed Autism

    1)  A study of interest (Whitely and colleagues, see below) was conducted regarding 1189 children age 3 to 11 formally diagnosed with various forms of Autism Spectrum Disorder, residing in the U.K. and Republic of Ireland, drawing on records received between 2002 and 2007.  The records showed that 65% of the children with those conditions had been “exclusively breastfed” for over four weeks.  After doing a search of available sources for a comparison figure for exclusive breastfeeding for over four weeks for the U.K. as a whole for the period in which those children would have been newborns, this author has come up with data from two different sources, which are consistent in leading to a figure of about 28%. (see below)  So the children who turned out to be autistic had been breastfed at a rate over twice as high as what the comparable figure would have been for the U.K. as a whole.  (Trends in Developmental, Behavioral and Somatic Factors by Diagnostic Sub-group in Pervasive Developmental Disorders: A Follow-up Analysis, pp. 10, 14   Paul Whiteley (Department of Pharmacy, Health & Well-being, Faculty of Applied Sciences, University of Sunderland, UK), et al.  Autism Insights 2009:1 3-17  at    Also:  Patterns of breastfeeding in a UK longitudinal cohort study, Pontin et al., School of Maternal and Child Health, University of West of England, Bristol, UK.   Whitely et al. looked at a comparison figure of 54%, but that figure was unrealistically high for the general UK population, since it came from a study (Pontin et al.) of breastfeeding by mothers who were largely from “more affluent families”, in the words of that study’s authors; more affluent mothers are well known to breastfeed at unusually high rates in countries in which breastfeeding is not nearly universal.  For breastfeeding prevalence data that would apply to the general U.K. population, the authors of the Pontin study referred the reader to (1) a 2005 study that showed a 33% rate at the end of the first month; note in Figure 1.9 and Section 1.2.s.6 of  that breastfeeding rates in the U.K. by 2005 (the year of the study that found the 33% rate) had risen about one-fifth just since the years of the births of most of the children whose data would have been reported in the Whitely study;  and (2) Pontin et al. also refer the reader to Infant Feeding 1995 (Foster et al.), which they say shows a 21% figure for exclusive breastfeeding for the next period following the first month; examination of the data in that book reveals that the 21% figure would apply at about eight weeks after birth, and that a figure in the upper 20%’s would apply at just after four weeks.)


    2)  In an investigation of rates of breastfeeding among 45 Kentucky children diagnosed with autism (Williams et al.), the percent of ASD-diagnosed patients who had been breastfed at 6 months was 37%, as compared with 13% in the control group (or 14% in the general Kentucky population).( Breastfeeding and Autism  P. G. Williams, MD, Pediatrics, University of Louisville, and L. L. Sears, MD, presented at International Meeting for Autism Research, May 22, 2010, Philadelphia Marriot  The authors (two MD's) determined a "P value" regarding the above finding of .003, meaning the odds of that difference resulting purely from chance, as opposed to from a causal relationship, are 3 out of 1000.  The odds that the greatly increased level of autism found in the Whitely study (with a 26-times larger study group) resulted merely from chance would probably have been even smaller than 3 out of 1000. 


    3)  In a U.S. study provided on the NIH website, looking at the correlation between autism and breastfeeding rates, observing data of all 50 states as well as 51 counties revealed, "there was a direct correlation (of increased autism rates) with the increasing percentage of women exclusively breast-feeding." And "the longer the duration of exclusive breast-feeding, the greater the correlation with autism.") (parenthetical expressions added) (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


Note that all of the above studies appear to support a finding that, the greater the exposure to breast milk, the greater the level of autism among the breastfed infants.  In the Whitely study, the duration of breastfeeding used for the comparison was only four weeks, a level that was met by about 28% of mothers in the study area.  In the Williams study, the duration of breastfeeding used for comparison was a full six months, a level met by only 13-14% of mothers in the study area.  The shorter duration of breastfeeding was associated with an approximately 130% (65/28) higher-than-normal level of autism.  The greater duration of breastfeeding was associated with an approximately 175% (37/13.5) higher rate of autism.  That same kind of "direct correlation (of increased autism rates) with the increasing percentage of women exclusively breast-feeding" and with the "longer duration" of breastfeeding was also found in the Shamberger study. 





* For information about Pollution Action, and to see a list of our other free online articles on the general subject of effects of breastfeeding, go to .