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Public Radio's Environmental News Magazine (follow us on Google News)

Mothers' Milk: A Modern Dilemma

Air Date: Week of

Nature's perfect food, breast milk, helps growing infants develop resilient immune systems. But along with the welcome antibodies are the persistent toxins mother may have ingested in her lifetime, which are stored in her fatty tissue and passed on to her baby. In 1996 reporter Andrea DeLeon was the nursing mother of a newborn. Her story on the toxins in breast milk won an award from the American Association for the Advancement of Science. Living on Earth re-airs the story and talks with Dr. Linda Birnbaum, head of the Experimental Toxicology Division at the EPA, for an update on what’s in mother’s milk today.


CURWOOD: It’s Living on Earth. I’m Steve Curwood. This Earth month we’re looking back at some of the best stories we’ve done over the past sixteen years and giving a few of the award-winners an encore. We head back this week to 1996, and a story about breastfeeding. It took a hard look at the toxins that can be found in breast milk, and the dilemma that poses for a nursing mother.

The story was reported by Andrea DeLeon, then of Maine Public Broadcasting, who had recently given birth to her second child. We asked Andrea to share both her findings and her feelings with us. Her report won a Science Journalism Award from the American Association for the Advancement of Science. We’ll take a listen to it now, and later we’ll check in with one of the principal scientists in the story to see what’s changed over the last decade. One thing that hasn’t changed is that most scientists agree that despite the health concerns, mother’s milk remains the best food for babies.

Here’s Andrea DeLeon.


DE LEON: That's my son Carter. Four months old and he still wakes me each night at about this time: 3 AM, hungry.


DE LEON: I can stumble to the cradle in the dark, now, without knocking into the rocking chair. I take him into my bed to nurse. He stops crying as we lie belly to belly under the covers in the dark. In this position I can bend my face down to kiss the top of his fuzzy head, to breathe his baby smell as I doze. In all the chaos of my days, the only word that even comes close to these moments is peace.


DE LEON: Peace at least until a month ago, when I tuned my car radio to a speech about a health threat long suspected by scientists but only now gaining public attention.

GIBBS: (on radio) Dioxin affects every man, woman and child. It comes from solid waste incinerators.

DE LEON: The speaker was Lois Gibbs, the Love Canal homemaker who turned activist when she discovered her neighborhood was built on a toxic waste dump. Her topic: dioxin and a host of other persistent toxic chemicals which, she says, are waging covert war on the human population.

Gibbs: It goes out into the air, it goes out into the water, it gets into our food supply. It gets into the cow. When the cow is milked, it gets into our bodies. And ladies and gentlemen, the top of the food chain is our infants. Women who are breast feeding their babies are the top of the food chain. So when the cow is….

DE LEON: That evening, when my son fell back, milk drunk and ruddy cheeked in my arms, I carried him upstairs with a sense of unease. Was he really as all right as he looked? I needed to know if my milk contained chemical time bombs that might wait half his life to go off. I called Dr. Beverly Pagan, a senior staff scientist at the Jackson Laboratory in Bar Harbour, Maine. She told me she hated to talk about contamination in breast milk, and then reluctantly agreed to meet with me.

PAGAN: Breastfed babies are taking in dioxin at a level that is 10 to 100 times more than an adult is getting. This is quite a serious issue. In fact, a breastfed baby takes in 10 to 15% of his entire lifetime dose during that first year.

DE LEON: Dr. Pagan told me that dioxin, PCBs, furans, and other persistent toxics have been entering my body in minute servings as part of the food I eat, and accumulating over my lifetime in my fatty tissues. I get my largest doses in meat, dairy fat, and freshwater fish. The older I get, the higher my levels become. When I nurse my son, Beverly Pagan says, toxics long stored in my fat migrate into the fatty breast milk.

PAGAN: Particularly, these chemicals are often an antagonist to the male hormone. These chemicals also might increase cancer in hormone target organs, such as breast cancer, testes cancer, prostate cancers. All 3 of these types of cancer are going up dramatically in America. And we don't know any reason, except for the exposure to these chemicals.

DE LEON: And there was more.

PAGAN: The sperm count in men has been falling. We think this is because of these hormone-disrupting chemicals, because most of them seem to interfere with the male hormone. We know that they can decrease sperm production in animals.

DE LEON: Breastfeeding is the only natural way humans can rid their bodies of some of these poisons, but with the demeanor of a friend breaking bad news, Pagan told me that most human mothers are carrying around enough chemicals to pose some threat to their children. But a single conversation and a couple of magazine articles didn't convince me that my own milk could bring harm to my baby. My bedside table sprouted stacks of literature on the subject. I read about the alleged dangers of nursing while nursing. I learned that the endocrine system is kind of like the postal service, delivering messages to all parts of the body, using cortisol to regulate my metabolism, releasing estrogen to trigger and modulate my reproductive cycles, telling my son's genes when to trigger each miraculous stage of his journey from egg to embryo to baby.

I needed someone to explain how chemicals in such small amounts could affect my hormone system and my child's as well. If my endocrine system is the postal service, toxicologist Linda Birnbaum explained that dioxins, PCBs, furans, and certain persistent toxics were keeping some of the mail from getting through, delivering letters to the wrong addresses, or forging messages of their own. I reached Dr. Birnbaum in North Carolina, where she heads the Environmental Toxicology Division at the Environmental Protection Agency's Health Effects Research Laboratory. She says that while there's a lot researchers don't know about how these chemicals do their work in the human body, they do know a great deal about the effects of dioxin.

BIRNBAUM: In some cases dioxins have been shown to increase the levels of hormone receptors, in other cases decrease. In some cases dioxin lead to changes in the transformation of hormones, so there are a number of ways in which compounds like dioxins or PCBs or other synthetic chemicals can impact hormone systems. There's not a single mechanism that can explain everything.

DE LEON: And higher levels of these chemicals do not necessarily mean more troubling effects on the body. But hormonal disruptions are blamed for everything from neurological problems to suppression of the immune system. Dioxin also appears to interfere with insulin. Hormonal effects have been documented in seagulls in Canada, in lab mice in Maine, and victims of an industrial accident in Italy. But none of this told me my son's risk. I weighed my years of vegetarianism against my fondness for tooling down the highway with a double cheeseburger balanced on my knees, my organic garden against the pint of ice cream in my freezer. I lay in bed in the middle of the night nursing, obsessing.

Beverly Pagan suggests that women have their milk tested, but such tests can cost hundreds to thousands of dollars, and with so many chemicals out there which would I test for? More importantly, what would I do with the results? My son has to eat something, and in the first months of life the choices are limited to formula or breast milk.

Everyone from the American Academy of Pediatrics to the formula manufacturers themselves says that breast milk is superior. Does the information coming to light about persistent toxic chemicals mean that's no longer true for some infants? Not from what scientists have learned so far. No one I talked with for this story told me to stop breastfeeding. Lactation consultant Bettina Pearson says a woman's breast milk is perfectly suited to her child at each stage of his development. It even serves as the infant's immune system in the first few months, until the infant's own immune system begins to function.

PEARSON: So in that interim, we’re providing our babies with our antibodies, and our antibodies are specifically a result of what our own environment is. So the antibodies I make, being exposed to my 5-year-old for a newborn child, would be different than someone else. And each of our environments, what we're exposed to for illnesses or, um, contaminants.

DE LEON: She says babies fed on breast milk spend less time in hospitals and have lower incidence of Sudden Infant Death Syndrome. They also have fewer infections and fewer allergies. I'm hoping Carter won't be plagued with the ear infection so common in young children. Though how my milk adapts to his needs remains something of a mystery. Bettina Pearson says formula could never show such response.

Dr. Birnbaum of the EPA says a study underway in the Netherlands demonstrates that even breast fed children born to mothers with high levels of contamination are healthier than formula fed infants whose mothers have similar levels of persistent toxics. But no one knows for sure whether breast milk actually counteracts some of the very contaminants it contains. Pregnant and nursing women are left to consider the evidence for themselves and discuss it with their caregivers. So far, these discussions seem to be few and far between. My own midwife says clients have only just begun to raise the issue. My search turns up no doctors and only one midwife who regularly discusses the issue with clients.

DANIELS: Let's take a listen. There we go. Got the heart, and I can feel the baby thumping around in there, too. There's a kick.

DE LEON: Midwife Ellie Daniels runs her hand over a young woman's rounded belly, conducting a routine prenatal exam.

DANIELS: I think the baby has the hiccups.

DE LEON: She warns her clients to avoid freshwater fish, and the clams and lobsters that are a staple for many of the coastal Maine residents in her practice. One hundred percent of the women Daniels cares for breast feed their babies: an incredibly high rate. She encourages me to continue.

DANIELS: What could we find that is better? I mean, any milk source is going to have dioxin contaminants in it. If you feed a soy formula, you're feeding a formula that's made from the most heavily sprayed soils in the country, you know, the Midwest, I mean, is in a terrible crisis with all of the chemicals that we've grown our crops with and sprayed on our crops. I mean, what can we find that is better? This is just a terrible situation.

DE LEON: This terrible situation is taking its toll on my breastfeeding experience, which was already almost as difficult as it is emotionally rewarding. I tote a breast pump and cooler everywhere I go, so that I can collect milk for my son when I'm not with him. It is a struggle to keep up with his needs and work full time. I eye the free samples of formula I brought home from the hospital.

Child health advocates worry that information about the potential contaminants in breast milk will drive women like me away from breast feeding, even though none of the scientists studying the effects of persistent toxics believe women should forego nursing. Lactation consultant Bettina Pearson says American culture remains anti-breast feeding. Women are criticized for nursing in public. Television programs show only bottle-feeding moms. And employers are sometimes unsympathetic to workers' needs to express milk on the job.

DANIELS: Breast feeding is so personal an experience, and I think women feel so vulnerable emotionally around it that if you're to say to them, um, you could be poisoning your baby, the last thing they're going to want to do is breast feed. So until we really know if there is a reason not to breast feed, even bringing it up, I think, is going to decrease the rates just because women are so conscientious about what they're doing.


DE LEON: I'm still breastfeeding, despite all that I've learned about contamination. Because I believe it's the best thing I can do for my baby. I'll try to mitigate his exposure at the breast by feeding him a diet low in animal fat when he's ready for solid food. The thing that strikes me is that these chemicals are already being reduced in the natural world, and that is good news. The fish caught in the rivers near my house last summer are cleaner than those taken the year before. But these same substances will persist in our bodies, in our breast milk, and in the bodies of our children. For Living on Earth, this is Andrea DeLeon.


CURWOOD: It’s been 11 years since we first aired that report, and to get an update on the science of toxins in breast milk, we called Dr. Linda Birnbaum. You just heard from her a few minutes ago in Andrea DeLeon’s story. She’s still head of experimental toxicology at the EPA and is a former president of the Society of Toxicology.

Dr. Birnbaum, welcome back to Living on Earth.

BIRNBAUM: It’s nice to be here Steve.

CURWOOD: So tell me. How has our knowledge of potential contaminants in mother’s milk advanced since Andrea Deleon first did that story back in 1996?

BIRNBAUM: I think we have more information on more contaminants being present in mother’s milk then we knew about 11, 12 years ago. The good news is that some of the contaminants, about which we had the most concern several years ago, the dioxins, the PCB’s, their levels are decreasing in mother’s milk just as they are in all of our bodies. I think some of the concern is, is that there are other contaminants whose levels are increasing in mother’s milk. And we’re also beginning to understand that it’s not only the fat-soluble chemicals. There are other persistent chemicals and then some non-persistent chemicals to which we’re exposed to everyday that are also appearing in mother’s milk and therefore being transferred to our babies.

CURWOOD: So tell me about these new chemicals that you’re paying attention to now along these lines.

BIRNBAUM: I think that there are maybe three major classes all of which have the ability, like the dioxins and the PCB’s, to affect our hormonal systems. The first class are some of the brominated flame retardants, some of the PBDE’s. And these chemicals in many ways are similar to the dioxins and PCB’s and therefore can get transferred to the nursing infant. So the levels of PBDE’s are going up while the levels of dioxins and PCB’s are going down. And there is growing evidence from animal studies that these PBDE’s can affect the developing nervous system, the developing reproductive system, and alter hormone signaling.

CURWOOD: And how about the other chemicals that you’re paying attention to now?

BIRNBAUM: Well, some of the other chemicals, the other persistent kinds of chemicals that we’re interested in, are some of the fluorinated compounds, the PFOS, the PFOA, the kinds of chemicals that are present like in kind of the lining of popcorn bags or in the nonstick finishes in cookware. And those compounds are persistent. They’re not very fat-loving but there’s a small amount that does get into the breast milk and therefore can also be transferred to the baby that way.

CURWOOD: So at the end of the day, this age old question of which is better, breast milk or formula for infants, where do you fall on this?

BIRNBAUM: I don’t think there is much of a question that breast milk is the optimal food for most babies. I think that it’s specifically designed over evolution to meet all the needs that a baby can have. And formula is the second choice for when, for some reason that the mother is not able to breastfeed.

CURWOOD: You know this is such a heart-rendering story. I mean here you have a mother looking at her child, wondering if she’s doing the right thing doing what mother’s have done, you know, for thousands upon thousands of years. Is there any good news in this story?

BIRNBAUM: I think knowledge is power and the more information that we have about what contaminants are present in our breast milk, it gives us the ability to talk about what we have to control and what we have to reduce. And finding the dioxin-PCB’s at high levels in breast milk 15 years ago led to a lot of the regulations that resulted in the decreased levels of those compounds in our bodies and in breast milk.

I think finding the elevated levels, for example, of the flame-retardants in breast milk has led to the producers voluntarily reducing the production of those chemicals. So I think when we find something in breast milk, if it’s a compound of concern, we know it’s there now, we can begin the steps to reduce it.

STEVE CURWOOD: Dr. Linda Birnbaum is head of Experimental Toxicology at the EPA and a former president of the Society of Toxicology. Thank you so much Dr. Birnbaum.

BIRNBAUM: My pleasure Steve.

[MUSIC: Colleen “Babies” from ‘Check The Water’ (The Leaf Label - 2006)]



Experimental Toxicology Division of the EPA


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