Dear Lactnet colleagues, I've been a subscriber to Lactnet for a couple of months now, but have been traveling so wanted to wait and send this introduction once I was home again. In the meantime, I learned that someone on the list made reference to an essay I wrote ("A Mother's Lament") and also posted an excerpt from a lecture I gave in Toronto a few years ago. This evidently prompted vigorous discussion on the issue of dioxins in breast milk (during the last week of April). Now that I'm back in town, I've had a chance to read the archives and can respond briefly. My apologies for joining the conversation belatedly. But first, my introduction. I'm a biologist at Cornell University and am associated with a project here called the Program on Breast Cancer and Environmental Risk Factors. Our primary objective is to examine the role that environmental contaminants play in contributing to breast cancer. In the capacity, we are very interested in how lactational history modifies breast cancer risk (i.e., is protective). My recent research specifically focuses on a number of questions related to lacation: 1) the life history of the breast from embryonic development through pregnancy, breastfeeding, weaning, and menopause; 2) the presence of chemical contaminants in breast tissue and breast milk and their possible relevance to a) breast cancer in the mother and b) developmental problems in the nurslings; 3) how the presence of breast milk contaminants changes through the period of lactation; 4) how the functioning of various constiuents of breast milk (e.g. immunoglobulins) may be compromised by the presence of chemical contaminants (e.g. immunosuppressive chemicals, such as PCBS and dioxins); and 5) how the presence of certain contaminants might interfere with milk production (possibly through endocrine disruption, e.g. prolactin and oxytocin pathways). I know that the chemical contamination of breast milk is a hot button topic, but I do feel that public health is never served by keeping secrets or failing to ask certain questions. I should add here that I'm a breastfeeding mother of a 2.5 year old and am now, at age 41, seven month pregnant with my second child, whom I hope to breastfeed at least as long (probably in tandem with my first born). Whenever I speak to the public--or to my colleagues in the sciences--on these issues, I always begin by stating that breast milk, however chemically contaminated, is still a far better food for babies than its inferior pretender, infant formula. Nevertheless, breast milk could be better still if we got the chemicals out of it--meaning out of women's bodies, which are the first environment for all of us, meaning out of the larger environment in which women's bodies co-exist. I usually conclude by saying that the goodness of breast milk has been compromised by the presence of chemical contaminants, and even though, thus compromised, it still does not injure babies as severely as formula does, we shouldn't wait until breast milk is as dangerous to infants as formula before taking action. Hopefully, my always acknowledged identity as a breastfeeding mother makes this message clear. In 1999, when I testified at the United Nations in Geneva on the issue of breast milk contamination, for example, I passed around a jar of my own breast milk so all the delegates could see that I was talking about a sacrament of motherhood, not toxic waste. I won't try to respond to all the issues and questions brought up on this list six weeks ago, but here are a few salient findings I've uncovered in the literature that may address some of them: --on average, breast milk is 10-20 times more contaminated with persistent fat-soluble chemicals (dioxins, PCBs, chlorinated pesticides) than cow's milk. This is because breast exists higher on the food chain, and these chemicals biomagnify with every link ascended. Infant formula is actually even less contaminated than cow's milk because its fats (oils) are derived from plants rather than animals. (This does not include pesticides that might be found in tap water, with which formula is often mixed.) --The U.S. does not have a breast milk monitoring program, so it's really impossible to know what's going on in this country. However, German and Dutch studies show that breastfed babies have significantly higher levels of persistent organic pollutants in their blood serum than bottle-fed babies. These differences persist through childhood, so that 3.5 year old children breastfed as infants still have 4 times more pcbs in their blood serum than children who had been formula fed. The longer the duration of breastfeeding, the higher the levels. --You can't get rid of dioxins by dieting. They have a half life of about 8 years in the human body. When you burn body fat, you don't metabolize the contaminants it contains; you simply release the dioxins stored there into your bloodstream. They then resettle in your remaining fat reserves, which you always have, even if you burn all your subcutaneous fat. (You have large reserves of fat in your liver, brain, adrenal glands, and in the lipid fraction of blood, for example.) That's the problem with dioxins and other fat-soluble persistent contaminants: you can't easily metabolize and pee them out. Lactation, which does remove fat from a woman's body, is the only effective way to "purge" dioxin from the body. (There are a couple of exceptions regarding bile duct excretion and the effect of chronic diarrhea, which I can explain in more detail if anyone is interested.) --The fat found in breast milk is mostly drawn from fat reserves laid down over a lifetime, not fat in the current diet. The best estimates that I've been able to find indicate that 60 percent of the fat in breast milk fat globules comes from body fat reserves, with only 30 percent from current diet, and 10 manufactured de novo in the breast itself. This is why breast milk contains such high levels of chemicals, like PCBs and DDT, which were banned for use years ago. The fat in the breast itself is normally not metabolized during lacation. --In spite of all this, as a group, breastfed babies still outperform their formula-fed counterparts on tests of intelligence, immunity, and psychomotor skills. However, the real test of whether breast milk contamination is harming babies would be to compare breastfed babies drinking contaminated milk with breastfed babies drinking contaminant-free milk. This study cannot be carried out because all women on the planet have contaminated breast milk. (DDT is the most widespread contaminant worldwide; PCBs are the most commonly found contaminant in the breast milk of mothers living in industrialized countries.) Therefore, the best we can do is to compare babies who receive breast milk that less contaminated than average with babies that receive breast milk that is more contaminated than average. The Dutch have done this. Their findings show subtle but measurable differences: babies whose mothers have less contaminated milk perform better on certain tests of infant development that babies whose mothers' milk is in the higher percentiles of contamination. --prental exposures to dioxins are actually less, not more, than breast milk exposures (10-20 times lower), but these smaller, earlier exposures still seem to be more significant in creating developmental problems later on. --levels of contaminants in breast milk drop rapidly with breastfeeding duraction. After six months, levels of organochlorines are 20 percent lower than those at birth. One U.S. mother of twins who nursed for three years dropped her body burden of dioxins by 69 percent. --first-born children receive more chemical contaminants than their later-born siblings, and older first-time mothers have higher levels of contaminants in their milk than younger first-time mothers. --the good news: the Swedish breast milk monitoring program, which is the gold standard and has been operating for 30 years, shows significant drops in dioxin and ddt levels since the 1980s. These drops reflect stricter European laws in the use and manufacture of these chemicals, incinerator closings, etc. That is to say, political action does work to clean up breast milk. Hope this is helpful. There is a wonderful new website, "Healthy Milk, Healthy Baby," about breast milk contamination, created by Dr. Gina Solomon at the National Resources Defense Council, if you want more details. It has a very pro-breastfeeding focus. The url is http://www.nrdc.org/breastmilk/ warmly, Sandra Steingraber -- -- Sandra Steingraber, Ph.D. Visiting Assistant Professor Program on Breast Cancer and Environmental Risk Factors 110 Rice Hall Cornell University Ithaca, NY 14853 [log in to unmask] www.steingraber.com *********************************************** The LACTNET mailing list is powered by L-Soft's renowned LISTSERV(R) list management software together with L-Soft's LSMTP(TM) mailer for lightning fast mail delivery. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html