What's in the Milk?

There was a discussion over at Brooke's about food safety in which I offered to provide more information about contaminants in human milk.  The most important thing I have to say on the topic is this:

Human milk for human babies.

Mostly what's in the milk is amazing stuff, like hypoallergenic proteins in a ratio that changes as baby's gut matures, to allow maximum digestibility for a tiny baby and longer intervals between feedings for an older baby.  Like lipase and other enzymes to help babies assimilate their food with less effort, less discomfort, and less waste (better-smelling waste, too).  Like sialic acid to promote neurological maturation.  Like oligosaccharides that fool pathogens in baby's gut -- because they resemble binding sites in the intestinal tract, they can intercept harmful bacteria.  Baby excretes them, no harm done.

I could go on about the miracle of human milk, but I've been there in other posts.  What else is in the milk?  Lots.  Much of what I have learned about contaminants in human milk comes from ecologist Sandra Steingraber's book Having Faith, the story of the gestation and infancy of her first child, Faith.  It is a wonderful book, lyrically and lovingly written, overflowing with information about and appreciation of the natural world.  It is also horrifying.  I first read it almost three years ago, when I was six months pregnant with Joe, and I panicked.  "Put that book down," counseled a well-meaning friend.  "Take a nice hot bath and read something fluffy."  "I can't," I sobbed, "because I just found out that inhaling water vapor is the most effective way to expose myself to the junk in my tap water."

I have since calmed down, and I am re-reading the book in spite of being pregnant again.  Here is some of what Steingraber has to say. 

Roughly sixty percent of the fat in a mother's milk is drawn from her body's fat reserves.  In those fat reserves are pollutants she's been exposed to over her lifetime -- perhaps including compounds she ingested in infancy with her own mother's milk.  Steingraber writes about the phenomenon of biomagnification, in which toxin concentrations increase tenfold to a hundredfold with each step up the food chain.  The cows eat the grass on which airborne dioxin has fallen.  The dioxin is stored in their fat; we eat the concentrated dioxin when we enjoy our steak dinners.  It is concentrated yet again in the milk we feed to our infants.  It is not unusual for mother's milk to exceed government limits for dioxin or PCB content by a large margin.  This is the stuff that makes headlines:  "Mothers' Milk Too Contaminated To Be Sold In Stores."

Those headlines, though, offer an incomplete picture.  They fail to say that choosing not to breastfeed has well-documented risks (this document seems to be an earlier version of ILCA's thoroughly referenced "Hazards of Infant Formula" monograph, available for purchase but not, as far as I can tell, published online in its current form).  They do not mention that every baby is exposed to carcinogenic pollutants in utero (as my baby spins and reaches and hiccups inside my womb, she is swallowing amniotic fluid laced with PCBs and other fetal toxicants), and that withholding mothers' milk from babies leaves them less well equipped to respond to immune system insults.  They rarely say that formula is far more likely than human milk to contain unsafe levels of lead and other heavy metals, or pathogens like enterobacter sakazakii. 

Dr. Jack Newman has pointed out that toxin exposure is typically associated with diminished immune response, increased cancer risk, and impaired neurological function.  Yet in comparisons of breastfed and formula-fed babies, it is formula-fed babies who have poorer immune function, higher risk of certain forms of cancer, slower neurological development, and decreased cognition.  At this time a risk-benefit analysis shows that breastmilk, polluted though it may be, is the clear choice for human babies.

I find that I have to fight my own knee-jerk reactions, though.  Some breastfeeding advocates act as if any questions about breastmilk safety are the work of Satan; in doing so they may overlook some important truths.  Formula does contain less dioxin than breastmilk because it has less animal fat.  Breastfed children have significantly higher levels of organochlorines in their body fat.  Breastmilk levels of PBDEs, the fire retardants which are also nasty persistent organic pollutants (POPs), have skyrocketed in recent years.  Steingraber cites some alarming studies in her book, troubling research into the effects of POPs on young children -- young breastfed children.  We can't ignore that.

So what's a mother to do?

Most importantly, don't panic.  If you see a story with a worrisome headline ("Breastmilk may cause babies to sprout additional heads"), read it with a skeptical eye.  Some useful questions:  Has it been published?  In a peer-reviewed journal?  Who funded the research?  What affiliatons turn up if you google the name of the lead investigator?

The $3 billion formula industry finances a substantial amount of research into human milk.  Their mission is to boost sales, not to provide breastfeeding mothers with the information they need to make informed choices.  If an alarming headline reaches enough women, some of them will decide not to breastfeed or to wean prematurely.  The vast majority of them will never know that the milk collection protocol skewed the results (if a mother expresses milk after a feeding, when the fat content of her milk is higher, lipophilic contaminants will be disproportionately represented), or that the study focused on first-time mothers in their 40s (who have higher body burdens), or that the peer reviewers laughed outright when they saw the statistical machinations necessary to arrive at the troubling conclusion.  If Dr. Selmore Boddles is the man behind the research and a formula manufacturer is buttering his bread, his conclusions may merit close scrutiny.

One of the most disturbing things about Having Faith is its portrayal of executives in a variety of industries who attempt to hush up truth in the interest of profit.  Her chapters on lead and mercury enraged me.  (Brief digression:  the lead industry refused for years to acknowledge that lead was a neurotoxin or that it was particularly harmful to children.  They submitted studies to Congress showing no ill effects from short-term exposure. (The damage takes some time to show up.)  Independently funded researchers who reached different conclusions were portrayed as hysterical.  And today we are all dealing with the consequences:  hundreds of thousands of children in this country with cognitive deficits arising from lead exposure; uncountable dollars spent on lead containment and abatement efforts.)  I submit to you Gladly's Cynical Saw:  when truth and profit compete, truth loses.  We can't forget that there is money to be made in persuading women of their bodies' inadequacies.

Even though the sensationalism is unwarranted, the fact is that human milk contains things most of us would not choose to feed our babies.  So if you are a woman in your childbearing years, you might consider lifestyle changes.  La Leche League has some suggestions. 

Personally, I've cut down my consumption of animal fat, especially butterfat (recent posts notwithstanding).  I don't eat freshwater fish and I try to stay low on the food chain when I eat ocean fish.  Salmon and tuna are occasional indulgences.  (I aim to eat mostly vegetarian food when I am not pregnant but I am torn just now:  my baby's developing brain needs abundant high-quality protein.  I crave meat.  Does the value of animal protein outweigh the risks of fetal toxicants in animal fat?  I think so, but I cannot be certain.)  To reduce pesticide exposure, last summer I split a CSA share of organic produce with a friend.  I keep in mind the "dirty dozen" report when I am in the produce aisle.

These choices will not make a huge difference, since most of the toxins in my body come from foods eaten long before I knew they could affect my children's well-being.  But I figure that we're talking about small increments here, and that small changes may be worth making.  Although Steingraber is not terribly optimistic about this approach to toxin control, there is at least some research suggesting it may be helpful.

To learn more about your individual situation, you can search by zip code for information on your air and water quality and toxic chemical releases in your neck of the woods.  The AAP does not recommend routine testing of breastmilk and encourages breastfeeding "in all but the most unusual circumstances".  But if you know that you have been exposed to especially high levels of toxins -- if you have spent the last ten years working at a dry cleaners, say -- you may want to find out more.

I have seen more radical suggestions.  Michel Odent has suggested that women fast before conceiving to lower their body burdens.  But that is an approach suitable only for a select group of women, and I believe that babies conceived unexpectedly and babies born to women who cannot afford organic food deserve pure milk just as much as babies in more affluent families do.  Steingraber reports another proposal which I find utterly preposterous:  the idea that women should pump and dump to decrease milk contaminant levels while also feeding their babies at the breast.  Why should the onus be on new mothers and not on the corporations spilling this muck into our air and water?

Some mothers think that breastfeeding briefly and then switching to formula will provide the benefits of their milk while simultaneously protecting against toxin exposure.  Unfortunately, Steingraber says pollutants in human milk are most concentrated during the early weeks.  Additionally, many of the benefits of breastmilk are dose-related:  babies breastfed briefly are better off than formula-fed babies, but they do not fare as well as babies who receive their mothers' milk into early childhood.  Babies cannot know about the polluted world they have been born into.  Mothers' milk is no less valuable to babies now than it was to babies a millennium ago.

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I have written this post slowly because I know so little of what there is to know.  If you spot errors, please let me know right away.  If you have other ideas about how to protect small children from pollutants, please leave comments.  Here are some places to learn more:

• Basic information for nursing mothers
• Reviews of books discussing breastmilk contamination
• Information on formula versus breastmilk
• More on chemicals in breastmilk

An appendix at the back of Having Faith lists many additional resources.

Let's not forget the value of political action designed to compel corporations to behave responsibly and to tell the truth about what they are doing to our world.  Keep an eye on the news from IPEN.  Write your legislators and ask why we are still pumping PBDEs into the environment when effective alternatives exist.  Research what's in your water supply and complain loudly if your children are not getting clean water.

And if your newspaper publishes an article with a sensationalistic headline like "Human Milk High in Toxins," let them know that you expect better.  Let them know that the answer is not to feed human babies the artificially modified milk of another species.  Let them know that contaminants in mothers' milk reflect a larger problem, and that the solution is far more complex than vilifying a much-needed natural resource like breastmilk.

Let them know that when they write about our bodies, and about our babies, they need to tell the truth.