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Toxins In Breastmilk - The Guardian

Hands up if you've read Saturday's Guardian article about toxins in breastmilk.  I have thanks to a few lovely people giving me a nudge, and it makes fascinating reading.  I think it's hugely important that information such as this hit the news, studying the environmental impact of our current way of living is vital - we can't put our heads in the sand.  If you haven't read it, it's really worth doing so before continuing with this entry.

You may be surprised to know that this information isn't new, Florence Williams hit the headlines with a strikingly similar article in the New York Times Magazine back in 2005, following the launch of her book.

Whilst statistics outlining percentage transfer of mum's toxic load to baby can sound scary - I think we need a little perspective,  to look at the big picture and examine exactly what risk breastfeeding confers compared to alternatives.

So let's go!  Brew up, I fear this may be long!

The piece opens with some interesting information about breastmilk and discussion surrounding its constituents - all good, and concludes with:
"If human breast milk, nature's perfect food, came stamped with an ingredients label, it would read something like this: 4% fat, vitamins A, C, E and K, sugars, essential minerals, proteins, enzymes and antibodies. It contains 100% of the recommended daily allowance of virtually everything a baby needs to grow, plus extras to help ward off a lifetime of diseases, from diabetes to cancer."
Although the "plus extras" list is so long I think it would need to be a pretty big label.  If you would like to see  a full list of what is in breastmilk click here.

The article then moves on to describe how because breasts store fat, they store toxic, fat-loving chemicals.

But it's not quite that simple. The level of toxins a mum releases in her breastmilk from this store is linked to her nutritional state.  If mum's diet causes her to start burning fat stores for energy, the toxins can be released from fat cells and therefore breastmilk levels would be higher.  The more rapidly this occurs (eg crash dieting, sudden famine) the more toxins can concentrate in breastmilk.

Many studies also suggest levels vary widely from area to area, country to country and mother to mother.  For example some show those living in rural areas have higher levels of some toxins due to crop spraying; smoking and other lifestyle factors - including how many toxins mum is exposed to on a daily basis..

Researchers from Ohio State and Johns Hopkins universities measured levels of volatile organic compounds (VOCs) in breast milk and in the air inside the homes of three lactating Baltimore mothers, finding that :
 "A nursing infant’s chemical exposure from airborne pollutants to be between 25 and 135 times higher than from drinking mother’s milk. (1)
Which is interesting

Florence then goes on to say:
"Despite the reassuring arguments to keep breastfeeding, I find myself unsettled."
Before quoting a rather bizarre quote from  Cathrine Thomsen of the the Norwegian Institute of Public Health:
"I don't think it will change the current recommendations [to breastfeed for a year], but maybe there's no benefit to breast-feeding after six months,".
Er right, but when it comes to the health of our babies, don't we need more than a "maybe"?  If there really isn't a benefit then surely they should change their guidelines, otherwise why recommend it?

I find myself mightily unsettled - and here's why

The article also reads:
"PFCs have spread across the globe, even ending up in polar bear tissue, and virtually never break down in the environment."
"The Inuit, although they live in the remote Arctic, are the most contaminated population on earth."
"A doctor named Morton Biskind, from Westport, Connecticut, examined a pregnant woman who had strange neuropsychiatric symptoms. He had been following scores of patients with acute poisoning from exposure to the pesticide DDT, which had hit the US market a few years earlier. He'd heard the substance was being found in the milk of cows, rats and dogs"
So if mothers avoid breastfeeding, the alternatives also pose a risk?

Some argue that cow's milk has lower levels of PCBs and dioxins than human milk, because cows are herbivores and are lower down the food chain; but the truth is formula is still affected by other toxins, including environmental pollutants.  What would we find in the milk from a cow grazing in a field next to a factory and a main road, supplemented with genetically modified feed?  Let's also not forget that infant formula isn't just cow's milk, but lots of other things - so there's potential for further toxins to be introduced including from fish oil.

A 2010 study entitled "Perchlorate exposure from infant formula and comparisons with the perchlorate reference dose" found:
Perchlorate was a contaminant of all commercially available powdered infant formulas (PIF) tested. The perchlorate RfD may be exceeded when certain bovine milk-based PIFs are ingested and/or when PIFs are reconstituted with perchlorate-contaminated water."
 A 2007 "Survey of Bisphenol A in U.S. Canned Foods" produced by the Environmental Working Group found:
"Of all foods tested, chicken soup, infant formula, and ravioli had BPA levels of highest concern. Just one to three servings of foods with these concentrations could expose a woman or child to BPA at levels that caused serious adverse effects in animal tests."
"For 1 in 10 cans of all food tested, and 1 in 3 cans of infant formula, a single serving contained enough BPA to expose a woman or infant to BPA levels more than 200 times the government's traditional safe level of exposure for industrial chemicals." (here)
This table shows the levels of Perchlorate found in different brands of infant formula:

We also need to consider that non breastfed infants are already known to be at increased risks of disease, SIDS, immune & thyroid issues.  That not receiving human milk causes physiological changes in the body still apparent in late adulthood eg the thymus (because substitutes lack so many constituents including growth factors and hormones).  And that the gastrointestinal tract bacterial profile is totally different in a non breastfed infant, which when we consider epigenetics is really quite worrying too.

Moving on to cancers, if we're going to avoid breastfeeding because we're concerned toxins could cause this, we should perhaps examine the evidence.
"Scientists have found a component in breastmilk called HAMLET can kill more than 40 types of cancers, including aggressive forms such as lung cancers & brain tumours. Crucially unlike any current cancer treatment, healthy cells are left unharmed." here
What numerous studies from the last 20 years tell us is that not breastfeeding increases a child's risk of leukemia and other childhood malignancies by as much as 50%.  Some studies have noted a dose response ie the longer the child is breastfed, the greater the impact.

Take note Norwegian Institute of Public Health

These are not studies dating back pre pollution, they are from the last 20 years - and what many may not be aware of is that levels of fat loving toxins such as DDT's and PCB's actually peaked in the 60's and 70's, with many levels decreasing (to various degrees) over the last 20-30 years.  Therefore at the time of these studies mothers must surely have been dumping toxins galore.

Despite this, the increase in cancer risk for non breastfed infants isn't just present at feeding age - but as the Denver study highlights 15 years after feeding has ceased (nobody has studied beyond this age that I can find).  This ties in with other studies confirming constituents of breastmilk can hang around in the recipients body for decades, waiting to step in and assist the immune system if required.

So it seems the evidence examining health outcomes wouldn't seem to echo suggestion that not breastfeeding is a safer option or something we can feel comfortable about.

And I think that's really the key - we need to examine not just what is in breastmilk or bovine substitutes - but what the impact of that is on the infant body.

Breastmilk contains thousands of constituents and scientists still have no idea what a huge chunk of them do, and perhaps more importantly how they interact with each other and with foreign contaminants.

However what researchers have recently discovered is that:
"breast-fed babies can metabolize the environmental contaminant perchlorate, decreasing their risks of detrimental developmental effects from exposure."
The key they discovered is bifidobacteria, naturally present in breastmilk. When the team added perchlorate to store-bought milk containing cultured bifidobacteria, the perchlorate was significantly destroyed.

This may go some way to explaining why other sources of PCB's have been associated with a negative neurological impact, yet studies have highlighted that even if high levels of PCB's and dioxin are in breastmilk, neurological status was still superior when compared to substitutes (3, 4)..

Another 2007 study found:
"Children who were breastfed for more than 20 weeks had better cognitive performance regardless of their in utero exposure to DDT. "(5)
Even earlier than this a study in 2000 concluded:
"Our studies showed evidence that breast feeding counteracts the adverse developmental effects of PCBs and dioxins."
 The Norwegian Institute of Public Health might want to jot that down too.

Formula may also become contaminated during the manufacturing process. In the past, recalls have been ordered because of substances such as broken glass, fragments of metal and salmonella and other bacteria.  And I'm sure nobody has forgotten the Chinese Milk Scandal.

The fungal toxin aflatoxin has also been detected in some commercial formulas. Although detected levels were very low, this toxin is known to cause cancer and is not present in breast milk. Infant formulas also may contain excessive levels of metals, including aluminum, manganese, cadmium and lead.

And what about the water it is made up with?

A report from National Geographic in 2009 found Cocaine, Spices & Hormones were amongst some of the ingredients found in American tap water   What's more:
"Keil and his team have tracked "pulses" of food ingredients that enter the sound during certain holidays. 
For instance, thyme and sage spike during Thanksgiving, cinnamon surges all winter, chocolate and vanilla show up during weekends (presumably from party-related goodies), and waffle-cone and caramel-corn remnants skyrocket around the Fourth of July. 
The Puget Sound study is one of several ongoing efforts to investigate the unexpected ingredients that find their way into the global water supply. 
Around the world, scientists are finding trace amounts of substances—from sugar and spice to heroin, rocket fuel, and birth control—that might be having unintended consequences for humans and wildlife alike.
The UK is no better:
"Over 300 different man-made chemicals have now been detected in British tap water. Water companies test for around 20 of these chemicals. These twenty chemicals are all present in varying amounts (for example DDT, Simazine, Atrazine, and 3,4 Benz pyrene, (weed killers)." here
Mmmmmm glass of water anyone?

Perhaps we should skip milk after 6 months altogether and just go for food.

Oh but wait that's problematic too.

A major study by the European Union in 2011 found a cancer-causing toxin at uncomfortable levels in common foods such as bread, jars of baby food and fried potatoes. They found intake of acrylamide, a chemical already classified as being of very high concern, has grown despite food safety efforts, and that babies face as much as triple the exposure of adults.

They noted that levels of acrylamide in crisp bread and instant coffee had risen and they had failed to come down in most other food products.  The highest levels of the chemical were found in samples of substitute coffee, at 3mg/kg, and potato crisps, at 4.8mg/kg.

The World Health Organisation has suggested a safe intake level of 0.5mg/kg of body weight for neuropathy, though safe levels for cancer are unknown.

Everything is sprayed with pesticides, don't even get me started on the chickens,  fish from contaminated oceans, animals given growth hormones - and that's without even venturing into the world of artificial sweeteners, E numbers, chemicals, perservatives and GM food.  Speaking of which what about contamination from GM to non GM crops from bees?
"The human uptake of dioxins and POPs is mostly from contaminated food products that originate from places with heavily polluted soil and water, and they can also enter the body through contaminated air." (Tze Wai Wong, an environmental epidemiologist at The Chinese University of Hong Kong.)
If breastfeeding presents interesting reading regarding toxins, let's consider the impact to the foetus during pregnancy.  

Since the 1970s, scientists have known that when DDT accumulates in a woman's tissues it can be transmitted to her developing foetus across the placenta.

A 2006 study from the University of Calfornia Berkley found that such in utero exposure to DDT, and to a lesser extent DDE  was associated with  neurodevelopmental delays during early childhood .

However just like the studies above,  they too found the longer the children nursed, the better they scored on developmental tests - even with mothers who had high accumulations of the pesticide in their bodies. (6)

In 1995 it was recognised that:
"Spontaneous fetal death has been observed among various mammalian species after exposure to polychlorinated biphenyls (PCBs)." here
 A 2004 study examining Foetal exposure to PCBs found:
"OH-PCBs and PCBs are transferred across the placenta to the fetus in concentrations resulting in levels of approximately 50 and 30%, respectively, of those in maternal plasma. More research in humans is needed to evaluate potential negative effects of these endocrine disruptors on the fetus." (7)
A study carried out by independent doctors at the Department of Obstetrics and Gynaecology, at the University of Sherbrooke Hospital Centre in Quebec, Canada found GM food toxins in the blood of 93% of unborn babies they tested. (8)

A 2007 study found:
"A critical window of exposure to DDE in utero may be the first trimester of the pregnancy, and psychomotor development is a target of this compound. Residues of DDT metabolites may present a risk of developmental delay for years after termination of DDT use." (9)
A 2008 study found:
"We observed a negative association of prenatal dichlorodiphenyltrichloroethane exposure and child mental development. We also observed adverse associations of prenatal but not postnatal organophosphate pesticide exposure with mental development and pervasive developmental disorder at 24 months." (10)
What we have to realise is that breastmilk is just a gauge, illustrating the typical pollution within the bodies of men, women and children.  Toxins have been found in umbilical fluid, cord blood and even seminal fluid (the latter of which is particularly sensitive to environmental toxins).  If the concerns regarding breastmilk is enough to make someone wonder if breastfeeding is a good idea, the information regarding inuterine exposure should act as a reliable contraceptive.  

This is not just about breastfed babies.

Sungroul Kim, lead author of the above study from Johns Hopkins states:

"We ought to focus our efforts on reducing the indoor air sources of these compounds,”.

It seems to me the problem is everywhere, so much so that "safe daily tolerable levels" are now in place for many toxins - there is no pretence of being able to avoid them. Sure manufacturers can aim to reduce levels of x or y in specific products, but there are so many and their reach so great.

If babies are going to be exposed in some way to toxins - why would removing the one substance that is shown to actively assist their body be desirable?

We need to look at what fluids such as breastmilk are telling us and about what is happening to our bodies and react with a much bigger knee jerk than "stop breastfeeding".

Perhaps the biggest irony in that is that the environmental impact of not breastfeeding is huge. Farming of cows is responsible for emitting high levels of methane if the cows are not pasture fed. Manufacturing substitutes uses vast quantities of energy and natural resources, and the production plants also contribute to pollution.

The production and packaging uses large amounts of paper, glass, plastic, and metals that are rarely recycled ( - which with the introduction of disposable bottles only seems to be increasing. It often travels long distances in lorries that burn diesel to supply hospitals and shops. Distributing infant formula also contributes to air pollution. Ecuador imports infant formula from the United States, Ireland, Switzerland, and Holland. China import from as far away as Holland

If every child in America was bottle fed, almost 86,000 tons of tin would be needed to produce 550 million cans for 1 year's worth of formula ( The majority of the cans and packaging used in the distribution of formula end up in landfills that contribute to groundwater pollution or incineration, which releases carcinogens like dioxin into the air.

Infant feeding products such as plastic bottles and teats also end up in landfills and it is estimated that they will take 250-400 years to break down.

Now considering 96% of UK mothers use some formula before 6 months, imagine how much pollution and thus toxin levels in breastmilk could be reduced if the majority exclusively breastfed...

Further Reading: Communicating human biomonitoring results to ensure policy coherence with public health recommendations: analysing breastmilk whilst protecting, promoting and supporting breastfeeding

Organisations: MOMS (make our milk safe) is a national grassroots movement of mothers working to create a healthier, safer environment for our children.
  • 1. Volatile Organic Compounds in Human Milk:  Methods and Measurements. Sung R. Kim,Rolf U. Halden, and, and Timothy J. Buckley* Environmental Science & Technology 2007 41 (5), 1662-1667
  • 2. Surveillance of DDT and HCH Residues in Infant Formula Samples and their Implications on Dietary Exposure: A Multicentre Study. Psticide Research Journal, 2001, Volume : 13, Issue : 2
  • 3. Koopman-Esseboom C, Weisglas-Kuperus N, de Ridder MA, et al. Effects of polychlorinated biphenyl/dioxin exposure and feeding type on infants' mental and psychomotor development. Pediatrics 1996;97:700-6.
  • 4. Patandin S, Lanting CI, Mulder PGH, et al. Effects of environmental exposure to polychlorinated biphenyls and dioxins on cognitive abilities in Dutch children at 42 months of age. J Pediatr 1999;134:33-41
  • 5. Beneficial Effects of Breastfeeding on Cognition Regardless of DDT Concentrations at BirthAm. J. Epidemiol. (2007) 166(10): 1198-1202 first published online September 22, 2007doi:10.1093/aje/kwm207
  • 6. In utero exposure to dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethylene (DDE) and neurodevelopment among young Mexican American children.Pediatrics. 2006 Jul;118(1):233-41.
  • 7. Fetal exposure to PCBs and their hydroxylated metabolites in a Dutch cohort.Environ Health Perspect. 2004 Aug;112(11):1208-12.
  • 8. Maternal and fetal exposure to pesticides associated to genetically modified foods in Eastern Townships of Quebec,Canada Aziz Arisa,b,c,∗, SamuelLeblancc 2011
  • 9 In utero p,p'-DDE exposure and infant neurodevelopment: a perinatal cohort in Mexico. Environ Health Perspect. 2007 Mar;115(3):435-9. Epub 2007 Jan 16.
  • 10. Pesticide toxicity and the developing brain. Basic Clin Pharmacol Toxicol. 2008 Feb;102(2):228-36.


  1. Thank you so much for such a comprehensive piece. I only read that Guardian article this morning and was outraged by some of her comments - I felt it really irresponsible to scaremonger about breastmilk when she just didn't discuss the alternatives and how they could be just as toxic. Frustrating that the Guardian choose to publicise such imbalance, too.

  2. Thank you so much. Really appreciate hearing the other side of the argument.

  3. Great -- thank you for this thorough and well-reasoned piece. One thing which bothered me about the Guardian article was that the author seemed to uncritically accept the suggestion that there were no benefits to breastfeeding beyond 6 months or maybe a year. How can a risk-benefit analysis be complete if no benefits are considered? There is so much research on it - best summary and listing I know of is on Kellymom at , and additionally for dental info see

  4. In my opinion the previous article seriously lacked objectivity and intended solely to grab attention.Thank you for this thorough approach.

  5. Great article, thank you so much for such an analytical review of published research. It basically says what I thought after reading the Guardian article but in a much more scientifically backed up succinct argument. I am glad to see that my gut reaction is validated however.

  6. Wonderful, thank you! What was so disconcerting about the Guardian article was that it felt so balanced, what with the first half being so positive, and being entitled "The wonders of breastfeeding". Deceptive or what.
    Sometimes I think The Guardian try to, position themselves away from breastfeeding in a shallow attempt to be less predictably middleclass. I am a Guardian reader but constantly gutted about their breastfeeding coverage.
    Excellent post, I will be sharing!


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